practice of medicine ii cardiovascular text 2008...

PRACTICE OF MEDICINE II

CARDIOVASCULAR TEXT

2008 EDITION

Allan Simpson MD Jonathan Christiansen MB ChB

Allan Simpson MD & Jonathan Christiansen MB ChB

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INTRODUCTION Welcome to the Cardiovascular section of the Practice of Medicine course. During this section we will help you learn how patients with cardiovascular disorders present, how to evaluate them, form a diagnosis and begin treatment. We hope to stimulate your interest in the evaluation and care of patients, especially those with cardiovascular disease. This text is an important component of the course. All the material you will need to prepare for the problem sets, small group cases and final examination is contained herein. The focus of this text is upon the foundations of clinical medicine. Particular attention has been given to the clinical history and examination that allow a physician to form a diagnosis and treatment plan. Emphasis has also been placed on pathophysiology, and how it relates to the presenting symptoms and signs of selected cardiovascular disorders. Treatment strategies change rapidly, so therapy is only briefly covered, emphasizing important principles rather than specific medication regimens. The text is now available on the UVA Cardiology internet educational site- (Cardiovillage.com). This has allowed the text to be enriched with multiple media, including color illustrations, heart sounds, movie clips of diagnostic studies, and interpretive aids. We think that this will significantly enhance your learning experience, and strongly encourage you to use the site. In addition to the text, we have added a set of “ECG Reading Exercises”, which will take you thru the entire reading process in a step by step fashion, culminating with brief clinical cases & ECGs which illustrate the clinical utility of the ECG. We also strongly recommend that you either read Dubin’s “Rapid Interpretation of ECGs”, or visit the ECG web site below- www.fammed.wisc.edu/pcc/ecg/ For cardiac auscultation, two websites are especially helpful, with good recordings and visuals- www.wilkes.med.ucla.edu/inex.htm www.dundee.ac.uk/medther/cardiology/hsmur.html For additional reading, a very helpful text for students is available online as well- www.merck.com/mrkshared/mmanual/section16/sec16.jsp Other sources include: Current Meical Diagnosis and Treatment, by Lawrence M. Tierney Harrison’s Principles of Internal Medicine, by Eugene Braunwald, el al. The goal of this course is to teach you a logical approach to evaluating cardiovascular disorders as they present themselves in patients. The lectures and small group sessions are designed to expand upon, and apply the information found in your reading, to clinical scenarios. Thinking and problem solving will be emphasized, as they are essential, lifelong skills that all physicians need master; we hope to cultivate them during this course.

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TABLE OF CONTENTS. SECTION A ...................................................................................................................................................7 APPROACH TO THE CARDIAC PATIENT ..................................................................................................7

1. COMMON PRESENTATIONS................................................................................................................................. 9

2. THE CARDIOVASCULAR PHYSICAL EXAMINATION ........................................................................................ 17

3. ELECTROCARDIOGRAPHY................................................................................................................................. 21

4. NON-INVASIVE IMAGING .................................................................................................................................... 49

5. STRESS TESTING................................................................................................................................................ 53

6. CARDIAC CATHETERIZATION............................................................................................................................ 57

SECTION B .................................................................................................................................................61 ATHEROSCLEROTIC CARDIOVASCULAR DISEASE.............................................................................61

1. ATHEROSCLEROTIC CARDIOVASCULAR DISEASE........................................................................................ 63

2. TREATMENT AND PREVENTION OF ATHEROSCLEROSIS............................................................................. 67

3. STABLE ANGINA .................................................................................................................................................. 71

4. ACUTE CORONARY SYNDROMES .................................................................................................................... 73

5. AORTIC DISEASES .............................................................................................................................................. 79

6. PERIPHERAL VASCULAR DISEASES ................................................................................................................ 83

SECTION C .................................................................................................................................................85 DISORDERS OF THE HEART....................................................................................................................85

1. HEART FAILURE .................................................................................................................................................. 87

2. VALVULAR HEART DISEASE .............................................................................................................................. 91

3. PERICARDIAL DISORDERS ................................................................................................................................ 98

4. HYPERTROPHIC CARDIOMYOPATHY............................................................................................................. 104

5. ADULT CONGENITAL HEART DISEASE........................................................................................................... 106

SECTION D ...............................................................................................................................................109 DISORDERS OF RHYTHM.......................................................................................................................111

1. BRADYARRHYTHMIAS ...................................................................................................................................... 113

2. TACHYARRHYTHMIAS ...................................................................................................................................... 116

SECTION E ...............................................................................................................................................119 HYPERTENSION ......................................................................................................................................121

1. HYPERTENSION ................................................................................................................................................ 121

SECTION F................................................................................................................................................127 PROBLEM SETS ......................................................................................................................................127 REFERENCE LIST....................................................................................................................................147 APPENDIX I GLOSSARY OF CARDIOVASCULAR TERMS 148 APPENDIX II GLOSSARY OF CARDIOVASCULAR MEDICATIONS 161

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SECTION A

APPROACH TO THE CARDIAC PATIENT

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1. COMMON PRESENTATIONS The heart’s primary function is to circulate blood throughout the vascular system. Anatomically it is comprised of four muscular pumps arranged in series, separated by valves, and regulated by an electrical system. When any of these components become sufficiently diseased or dysfunctional, they give rise to recognizable symptoms, most commonly chest pain/discomfort, shortness of breath, or syncope and/or palpitations. A. CHEST PAIN This is the most common symptom leading to a cardiovascular evaluation and is the most frequent reason that patients go to an emergency room. Some of the possible causes, such as ischemic heart disease, aortic dissection, and pulmonary embolus are immediately life threatening. Thus, a rapid and accurate diagnosis is essential, with especial attention to the more serious or life threatening possibilities. The differential diagnosis of chest pain includes:

• ischemic heart disease • aortic dissection • pulmonary embolus • pericarditis • pneumonia • pleurisy

• pneumothorax • gastroesophageal reflux/spasm • peptic ulcer • cholelithiasis • anxiety/neuromuscular • musculoskeletal

1. History

The most important portion of the evaluation is the history. It will provide the foundation for reaching the correct diagnosis, and lay the framework for selecting proper studies to confirm the diagnosis. Ischemic heart disease is the most commom life threatening cause of chest pain, thus most chest pain evaluations begin with this possibility in mind. Typical ischemic chest pain is described as a feeling of:

• pressure • tightness • squeezing • elephant on chest

• breathlessness • burning • fullness • unable to describe

Note that while we often refer to this group of symptoms as “chest pain”, patients themselves often deny they are having pain, and refer to their symptom as a discomfort, and use one or more of the descriptors above. The pain or discomfort is most commonly located in the substernal area, but may occur in the following areas as well:

• anterior neck/jaw • shoulder(s) • arm(s), ulnar distribution • hand/wrist, ulnar distribution • epigastric area • back, interscapular


The discomfort may involve only one of these areas, or may start in one area and spread or radiate to one or more additional areas. The most typical presentation would be substernal pressure, with a feeling of breathlessness. Women will often have epigastric, gastrointestinal-like symptoms.

Chronic ischemic symptoms, i.e. angina pectoris, typically are provoked by activities or conditions which increase the heart rate and blood pressure, thereby increasing oxygen demand of the myocardium. Because of a narrowing or partial blockage in an artery supplying the heart, this increased demand cannot be met. Relief is obtained by resting, relaxing or using sublingual nitroglycerine, all of which reduce oxygen demand. In contrast, patients presenting emergently generally have had the onset of symptoms while inactive, due to plaque rupture and complete occlusion of an artery, thus reducing oxygen supply. If nitroglycerine is used, it often fails to relieve the discomfort, as the occlusion is unaffected.

Ischemic symptoms generally begin as a mild discomfort and build to a peak over several minutes. If relieved by nitroglycerin or other measures, they generally resolve over 3 to 5 minutes. If unrelieved, additional symptoms such as shortness of breath, nausea, weakness, diaphoresis or near syncope usually begin to occur. If ischemia persists more than 15-20 minutes, myocardial necrosis/infarction begins.

Pain characteristics which suggest a non ischemic etiology include:

• sharp, shooting, twinge, lasting a few seconds • pinpoint size • lateral chest, “here over my heart” • present most of the time, for days • posterior neck, or outside of arm(radial distribution) • unlike previous heart symptoms • pleuritic nature • improvement with deep, slow inspirations (relieves muscular tension in chestwall)

Because symptoms more typical of ischemia may be present in other conditions as well, such as esophageal reflux, the presence of “atypical” symptoms listed above may be more helpful in narrowing the diagnosis and excluding myocardial ischemia. 2. Physical Examination

A careful and full examination is necessary in all patients presenting with chest pain. While there is no physical finding diagnostic of acute myocardial ischemia, most patients having a myocardial infarction do appear to be uncomfortable, and viscerally ill. Some will be extremely compromised due to pulmonary edema and/or cardiogenic shock. In contrast, patients being evaluated for possible angina pectoris are generally pain free at the time of their examination in clinic. Therefore, their examination may be perfectly normal, but findings of atherosclerosis should be rigorously sought, such as xanthalasma, xanthomata, peripheral vascular disease (reduced pulses) and bruits in any of the larger vessels.

Physical findings of non ischemic causes of chest pain are generally more helpful and should be vigorously sought as well. Examples include:

• aortic dissection: unequal or absent pulses, new/changing bruits, new murmur of aortic

insufficiency • pericarditis: pericardial friction rub • pulmonary: pleural friction rub, localized crackles or wheezes, absent breath sounds • gastrointestinal: abdominal tenderness - especially epigastric or upper quadrant(s) • anxiety: general affect, muscular tightness in neck and shoulders • musculoskeletal: localized areas of pain in the chest wall

Similar to “atypical” chest pain symptoms, these non-ischemic physical findings are more specific to an etiology, and therefore they are often more helpful to reaching a diagnosis when present.

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3. Chest X-ray

As with the physical examination, there are no specific x-ray findings of myocardial ischemia. However, with extensive ischemia (causing impairment of myocardial function), pulmonary edema may be present. The presence of pulmonary edema and a normal cardiac silhouette is extremely suggestive of acute myocardial ischemia. X-ray findings of non ischemic causes of chest pain are generally more helpful. Examples include:

• aortic dissection: widened aortic arch or mediastinum • pulmonary: pulmonary infiltrate, collapsed lung, unequal vascularity • gastrointestinal: diaphragmatic hernia • musculoskeletal: rib fractures

4. Electrocardiogram

The electrocardiogram may be very helpful in the evaluation of chest pain. Myocardial ischemia may cause either ST segment elevation or depression. While there are other causes of such changes, the hallmark of ischemia is its transient nature. Therefore, it is important to obtain an ECG during chest pain and to compare it with previous ECGs, or lacking old ECGs, to repeat the ECG at 5 - 10 minute intervals or when pain-free. Please refer to the ECG Learning Course for a more detailed discussion of these findings. Dynamic ST segment depression, present only during chest pain, strongly suggests the presence of myocardial ischemia, that is, angina pectoris. New or evolving ST segment elevation during chest pain strongly suggests the presence of an acute myocardial infarction. In addition, the ST segment elevation of infarction is usually localized to a coronary artery territory. Diffuse ST segment elevation may be seen in the early stages of pericarditis. Non cardiac causes of chest pain generally will not cause new ECG changes to appear, although T wave inversions may sometimes occur with pulmonary and gastrointestinal disorders.

5. Laboratory Studies

If chest pain symptoms persist beyond 15-20 minutes, laboratory evaluation may be helpful. Myocardial necrosis will cause the release of cardiac enzymes, including troponin I and T, creatine phosphokinase, myoglobin and lactic dehydrogenase. They will become measurable 4 to 12 hours after the onset of necrosis, depending upon the enzyme measured. Typically, only troponin I is routinely measured.

Other lab tests including hepatic enzymes, amylase and WBC count may help confirm non cardiac etiologies.

6. Disposition

After completing the steps above, the clinician must develop a working diagnosis, and then make a disposition. In the emergency room setting, roughly 25% of patients will have either a non cardiac etiology or be at low risk to sustain a cardiovascular complication, and may be discharged. An equal number will clearly have an acute ischemic/coronary syndrome or other potentially life threatening etiology and will need to be hospitalized.

The remaining patients will be of intermediate risk or likelihood to have an acute or unstable coronary condition, and will need further evaluation to clarify their diagnosis and disposition. Generally this is accomplished with a stress test, which will further risk stratify patients into either low or high cardiovascular risk, and allow for appropriate disposition. (see stress testing, pages 53-56)

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B. SHORTNESS OF BREATH Congestive heart failure is the most common cardiac cause of shortness of breath, or dyspnea, but there are many other cardiac and non cardiac etiologies. A representative differential diagnosis would include:

CARDIAC

• congestive heart failure • myocardial ischemia • pericarditis • pericardial constriction and/or tamponade

NON-CARDIAC

• obesity/deconditioning • metabolic disorders, eg acidosis • endocrine disorders • pneumothorax • anemia/anxiety • chronic pulmonary disease • pulmonary embolus • pneumonia

With so many possible causes, the history and physical exam become especially important to help guide and limit the evaluation. 1. History

Most patients with cardiac disease will experience dyspnea only with physical activity. However, if severe ventricular dysfunction is present, symptoms of orthopnea and paroxysmal nocturnal dyspnea (PND) will occur. Orthopnea is shortness of breath in the recumbent position, and is common to all cardiac causes of dyspnea. It may also occur with severe obesity, but is uncommon with chronic pulmonary disease. PND is the acute occurrence of dyspnea ½ - 2 hours after recumbency. This occurs as peripheral, third spaced fluid is resorbed, expanding the vascular compartment, and is extravasated into the lungs.

Other helpful history includes the presence of a cough (dry or productive), pleuritic pain, fever, observed blood loss, and a past history of myocardial infarction, valvular disease, pulmonary disease, renal disease or anemia.

2. Physical Examination

Physical examination is helpful in determining the cause of shortness of breath. Helpful findings by diagnosis include:

• CHF: cyclic respirations, elevated neck veins, pulsus alternans (alternating weak pulse-strong pulse), rales,

ventricular gallop (S3), displaced or enlarged cardiac apex, significant murmur, peripheral edema.

• Pericardial disorders: elevated neck veins, Kussmaul sign (elevation of neck veins with inspiration), paradoxic pulse (exaggerated fall of systolic blood pressure with inspiration), clear lungs, pericardial friction rub, ascites, peripheral edema.

• Pulmonary disorders: barrel chest, reduced breath sounds, ronchi, wheezes, dry crackles, localized moist

crackles, pleuritic rub.

• Anemia: pallor, tachycardia, orthostasis, absence of other findings.

• Anxiety: affect, diaphoresis, sigh breathes, absence of other findings.

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3. Chest X-ray

The chest x-ray may be helpful, especially for congestive heart failure and some pulmonary causes. With congestive failure, especially systolic failure, the cardiac size or silhouette is increased. In addition, there may be a redistribution of venous flow to the lung apices, prominent fissures, Kerley B lines, and pleural effusions. Pulmonary findings might include hyperaeration and bullae, depressed diaphragms, collapsed lung, consolidation from pneumonia or mass, and diffuse fibrosis.


The electrocardiogram has no specific findings of congestive heart failure, but may reveal evidence of possible causes such as:

prior myocardial infarction(s), left ventricular aneurysm, ventricular hypertrophy, or significant dysrhythmia such as rapid atrial fibrillation.

Pericardial constriction may produce reduced voltage and a rightward axis, while a large pericardial effusion may produce reduced voltage and electrical alternans.

Chronic pulmonary disease and obesity may again produce reduced voltage and a rightward axis, while a pulmonary embolus may produce acute changes including an incomplete right bundle branch block with T wave inversions across the anterior precordium. (these findings are discussed in the chapter on Electrocardiography)

5. Additional Studies

When considering cardiac etiologies of dyspnea, the most helpful additional study is the echocardiogram. It provides anatomic information such as the size of each cardiac chamber, presence of pericardial fluid, valvular deformities, and congenital abnormalities. It also provides physiologic information such as ventricular function, valvular function, tamponade, and pulmonary pressure. Thus echocardiography provides the opportunity to both identify the cardiac etiology, and to quantify the degree of physiologic impairment.

The echocardiogram may indicate the need for further evaluation, such as a stress test or cardiac catheterization. Stress tests provide functional information such as exercise capacity, and are also used to screen for the presence of coronary artery disease. Cardiac catheterization provides additional physiologic information, and provides visualization of the coronary arteries. A thorough discussion of these studies and their uses is present in the following chapters.

Most patients presenting with congestive heart failure will need hospitalization for acute treatment and evaluation.

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C. SYNCOPE Syncope, the transient loss of consciousness, will be experienced by 1/3 of all adults, while even more will suffer repetitive bouts of pre syncope, the near loss of consciousness. Following a syncopal episode, many patients will seek an emergent evaluation, and comprise 3% of all emergency room visits. Unfortunately, due to the transient nature of syncope, most patients will have returned to their normal status prior to being evaluated, limiting the observations to be made. Consequently, a diagnosis is made less than 50% of the time. There are many causes of syncope, both cardiac and noncardiac. Common to the cardiac etiologies is a drop in blood pressure leading to cerebral hypoperfusion. The pressure will generally have dropped to less than 50mmhg for at least 20 or 30 seconds. A differential diagnosis would include:

• Cardiovascular causes Dysrhythmia, tachycardia or bradycardia vasodepressor syncope carotid sinus hypersensitivity orthostasis/autonomic dysfunction obstructive ventricular outflow tract lesions, valvular and nonvalvular ischemic heart disease, often due to ventricular tachycardia aortic dissection pulmonary embolus

• Neurogenic causes seizure disorder cerebrovascular accident (CVA) head trauma

• Metabolic causes hypoglycemia alcohol/drugs hypoxemia hyperventilation/hypocapnia

1. History

If a diagnosis is to be made, it will most likely arise from information gathered in the history. Unfortunately, patients frequently will have only partial recall of symptoms prior to their syncopal event, and limited information about their recovery. They will obviously have no information regarding the period of absent consciousness. It is therefore imperative that any witnesses be interviewed as well. If they were summoned, EMTs should be interviewed or their records reviewed, especially their initial observations, such as state of consciousness, skin color, blood pressure, pulse rate, blood sugar, heart rhythm, evidence of trauma from seizure or fall, etc.

1. Dysrhythmias typically cause an abrupt loss of consciousness, with no prodrome. Patients frequently fall

hard enough to sustain significant injuries to the head, or suffer fractures. Recovery of normal consciousness is also rapid, provided a concussion has not occurred.

2. Vasodepressor syncope is vagally mediated, and typically has a prodrome, consisting of weakness,

diaphoresis, and nausea. It may be triggered by emotional disturbance such as witnessing an accident or seeing blood, or be brought on by prolonged upright posture. It almost always occurs when a patient is upright, and is caused by abnormal autonomic reflexes leading to venous pooling and inappropriate sinus bradycardia. Patients usually slump to the ground, and almost never suffer injuries. It may be aborted if the patient lies down during the prodrome. There is a rapid return to normal after the event. Similar abnormal reflexes lead to syncope in patients with a hypersensitive carotid sinus, usually triggered by stretching the neck to look upward or sideways.

3. Orthostatic syncope occurs abruptly after standing, usually in the setting of dehydration, recent blood loss,

or severe peripheral neuropathy.

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4. Obstructive cardiac lesions, such as aortic stenosis and hypertrophic obstructive cardiomyopathy, lead to syncope during or immediately following physical exertion, setting them apart from other cardiac causes.

5. Aortic dissection and pulmonary embolus are usually associated with chest pain and/or other symptoms,

such as shortness of breath.

6. The neurogenic causes of syncope are recognized by seizure activity, followed by the post ictal state, eg loss of memory; or an abrupt, severe headache prior to syncope.

7. Metabolic causes should be suspected if there is a history of severe diabetes mellitus, or of self abusive

behavior. 3. Physical Examination

The exam focuses on the demonstration of abnormal vascular reflexes, eg excessive orthostatic changes in blood pressure and/or heart rate, or a hypersensitive carotid sinus with compression causing 3 or more seconds of asystole. Evidence of peripheral atherosclerosis is also sought.

The cardiac exam looks for evidence of left ventricular outflow obstruction, fixed (aortic stenosis) or dynamic (hypertrophic obstructive cardiomyopathy). Thus the delayed central pulse, sustained apical lift and late peaking murmur of significant aortic stenosis are sought. Auscultation with the patient supine and standing should also be performed, to look for evidence of the dynamic obstruction caused by hypertrophic obstructive cardiomyopathy.

Neurologically, look for evidence of a seizure, eg tongue biting or incontinence, abnormal reflexes or neurologic deficit, and evidence of peripheral neuropathy.


The electrocardiogram may reveal evidence of dysrhythmia, such as sinus node dysfunction or AV block, or predisposition for dysrhythmia, such as shortening of the PR interval (pre excitation/atrial dysrhythmias) or prolongation of the QT interval (ventricular dysrhythmias). Findings of structural damage, such as previous infarcts or ventricular aneurysm, would also suggest the possibility of dysrhythmia, especially ventricular.

Other helpful abnormalities might include left ventricular hypertrophy, suggesting the presence of aortic stenosis or obstructive cardiomyopathy, or findings of right ventricular hypertrophy, suggesting the presence of pulmonary hypertension.

5. Additional Studies Any additional studies obtained should be based upon information gleaned from the history, physical examination and resting ECG.

1. If a dysrhythmia is suspected:

• echocardiogram: to look for stuctural abnormalities of the heart leading to dysrhythmia

• ambulatory monitor: 24 hour Holter or 4 week looping monitor to detect dysrhythmia • stress test: to provoke dysrhythmia or detect ischemic heart disease • cardiac catheterization: for patients with ischemic disease or ventricular dysrhythmias • electrophysiologic study: to further assess the conduction system and provoke dysrhythmia.

many dysrhythmias may be definitively treated with catheter ablation, an extension of the electrophysiologic (EP) study.

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2. If vasodepressor syncope is suspected:

• tilt table testing: to demonstrate the abnormal physiology, and test possible drug treatments.

3. If structural heart disease is suspected:

• echocardiogram: assess ventricular function, and valve function. • stress test: to detect ischemic heart disease • cardiac catheterization: to further assess ischemic heart disease, obstructive valvular disease, and

ventricular function.

If a patient’s initial evaluation suggests a possible life threatening etiology, they should be hospitalized for observation and telemetry monitoring (continuous monitoring of the heart rhythm) until their evaluation has been completed. Despite this, as stated earlier, nearly 50% of the time the evaluation will be unrevealing of the cause of the syncopal event.


2. THE CARDIOVASCULAR PHYSICAL EXAMINATION Despite the development of elegant technologies which can provide detailed information regarding the cardiovascular system, the physical examination remains a very important part of the evaluation of the cardiac patient. It frequently allows the examiner to make a diagnosis, eg valvular heart disease, as well as to assess the severity or degree of dysfunction caused by a disorder. Such information will assist in both the management of the patient and the selection of studies necessary to further the evaluation. The examination can be broken into several key components as follows:

1. General Appearance

The examination begins the moment the patient is encountered. Observations should be made regarding the patient’s:

• comfort level: anxious, uncomfortable from pain, or short of breath • body habitus: aesthenic, obese, cachectic, edematous, musculoskeletal abnormalities • skin: pallor, rubor, cyanosis, diaphoresis • cardiovascular motions: chest wall motions from cardiac enlargement, upward head bobbing from aortic

regurgitation, lateral head bobbing/ear lobe “waggling” from tricuspid regurgitation

2. Jugular Venous Pulse

The normal jugular venous pulse, JVP, consists of two positive waves named “a” and “v”, and two negative waves or descents named “x” and “y”. A third positive wave, the “c” wave, is present in the right atrium, but is too small to be seen in the JVP. The “a” wave is produced by atrial systole, and the “v” wave by filling of the right atrium during ventricular systole when the tricuspid valve is normally closed. The “x” descent occurs with atrial relaxation, while the y descent occurs with ventricular relaxation and opening of the tricuspid valve.

To examine the jugular venous pulse, the patient must be carefully positioned, generally semirecumbent, to bring the JVP into view. The internal jugular waveform should be examined as it is more reliable than the external jugular. However the latter may be used if the internal jugular is not visible. Both height and waveform should be assessed. The height reflects the right atrial pressure, and is estimated as the vertical height in centimeters from the midaxillary line/fifth intercostal space, which approximates the mid right atrial level, to the peak of the JVP. It should normally be less than 10cm. If normal, hepatojugular reflux should be tested in order to detect right ventricular dysfunction. To do this, the right upper quadrant of the abdomen is compressed for 10-15 seconds while the JVP is observed. If the JVP rises, ie: hepatojugular reflux occurs, right ventricular dysfunction is present.

The JVP should be observed through several respiratory cycles. Normally, the JVP falls with inspiration. If it rises, eg a Kussmaul sign is present, one should suspect the presence of constrictive pericarditis. Less common causes include right ventricular infarction, severe pulmonary hypertension, and restrictive cardiomyopathy.

To examine the waveforms, the radial pulse or the contralateral carotid pulse should be palpated while the JVP is observed. This helps determine the timing of the waveforms. Helpful findings might include:

• irregular waveforms: arrhythmia, especially atrial fibrillation • cannon a waves: large a waves produced by atrial contraction against a closed tricuspid valve, seen

with PVC’s or complete AV block

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• dominant v wave: tricuspid regurgitation • loss of x or y descents: cardiac tamponade • accentuated y descent: pericardial constriction, restrictive myopathy, tricuspid regurgitation

3. The Arterial Pulse

All accessible arteries should be examined, noting absence, diminution or hyperdynamic feel. The carotids, aorta and femoral arteries should be auscultated for bruits; the abdominal aorta palpated for aneurysm. The upper and lower extremity pulses should be checked simultaneously for the lag of coarctation. Capillary refill should be checked in a digit pad, and the nailbed checked for a hyperdynamic circulation, eg a Quincke sign, seen with severe aortic regurgitation.

The central arterial pulse should be assessed with attention to RATE, RHYTHM and CHARACTER. Helpful observations and the associated abnormalities include:

• pulsus alternans (alternating strong & weak pulses): reduced left ventricular function • parvus et tardus (a slow rising/peaking central pulse): aortic valve stenosis • spike dome (a quick upstroke followed by a slow/sustained peak): dynamic venticular obstruction • pulsus bisferiens (a quick pulse with double peak): aortic regurgitation

4. Precordial Examination

The precordium should be both observed and palpated. To observe, the patient should be supine. Look for any rhythmic movements in the left precordial area. Except for very thin individuals, the precordium is normally quiet. Therefore, perceptible movements suggest cardiac enlargement or a hyperdynamic circulation. To palpate, the patient should again be positioned supine. The palm should be used to sequentially palpate the right and left parasternal areas, and the apex. The apex should be sought with the second and third finger tips. If the apex cannot be felt, the patient should be rolled approximately 45 degrees to the left, which generally swings the apex closer to the chest wall, facilitating its detection. The NORMAL apex is found in the 5th intercostal space, in the mid-clavicular line. The apical impulse should be characterized, eg size, and duration, and note made of additional movements from gallops. If outward movement is felt in the parasternal areas, then both hands should be used to simultaneously feel the apex and parasternal area. Helpful findings and associated abnormalities might include:

• sustained apical impulse: significant aortic obstruction • hyperdynamic apical impulse: significant mitral or aortic regurgitation • atrial gallop: hypertrophied or stiffened ventricle • ventricular gallop or filling wave: volume overloaded ventricle, systolic failure • parasternal heave: right ventricular hypertrophy or severe mitral regurgitation

5. Auscultation

Auscultation is the last portion of the cardiovascular examination. For the skilled examiner, it mainly confirms the suspicions raised during the earlier portions of the exam.

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Most examiners begin with the patient supine, and listen over the mitral area, eg halfway between the apex and the tricuspid area (fourth intercostal space, left sternal border). Listening with the diaphragm, the stethoscope is sequentially moved to the tricuspid area, the third intercostal space, the second intercostal space (pulmonic area), the right intercostal space (aortic area), then the apex. One must focus on the normal heart sounds separately, and observe any abnormalities in their behavior, or associated abnormal sounds such as clicks or ejection sounds. Then one listens in systole and diastole separately for high pitched murmurs. The stethoscope is then changed to the bell setting, and the apex, mitral and tricuspid areas reexamined to detect the lower pitched sounds of gallops or a mitral stenosis murmur. If possible, the patient should also be listened to in the left lateral decubitus and upright positions. A partial listing of possible findings includes:

• abnormalities of the first heart sound

increased intensity: short PR interval, tachycardia, increased transmitral blood flow (mitral regurgitation) decreased intensity: prolonged PR interval, bradycardia, stiffened mitral valve, acute aortic regurgitation,

severe congestive failure

• abnormalities of the second heart sound

increased intensity of P2 : pulmonary hypertension reduced intensityof A2 : aortic stenosis wide splitting: right bundle branch block fixed splitting: atrial septal defect reversed (paradoxic) splitting: left bundle branch block, right ventricular pacing

• ejection sounds- high pitched sounds of valve opening

bicuspid aortic valve aortic stenosis, mild/moderate pulmonic stenosis, mild/moderate • clicks, mid systolic: mitral or tricuspid valve prolapse

• opening snap: mitral stenosis - heard just after S2, at the apex

• S4 or atrial gallop : stiffened, hypertrophied ventricle, diastolic dysfunction - heard just prior to S1

• S3 or ventricular gallop : volume overloaded ventricle, systolic failure, hyperdynamic state - heard in early diastole

• pericardial friction rub: pericarditis - typically has 3 separate components, corresponding to atrial systole,

ventricular systole and ventricular relaxation Murmurs

Several observations are made to characterize a heart murmur. They include:

• timing- diastolic or systolic • location of greatest intensity- apex, mitral area, etc • radiation- heard in the neck, back, etc • respiratory variation- yes/no • pitch- high or low • quality- scratchy, musical, blowing, honking, rumbly • configuration/shape- crescendo/decrescendo, flat/plateau, decrescendo • duration- holosystolic, late systolic, early diastolic, continuous, etc. • loudness- there are six grades: grade I barely audible with special attention grade II soft, but readily heard grade III moderate grade IV moderate/loud, and palpable grade V very loud and palpable grade VI very loud, palpable and heard with stethoscope just off the skin surface

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Murmurs are caused by turbulence of the blood flow thru the heart or valves. Systolic murmurs may be due to valvular disease, intracardiac shunts, or to increased blood flow such as occurs with exercise or pregnancy. Thus they may be caused by abnormal forward flow, called ejection murmurs, or backward flow, called regurgitant murmurs. Many times it may be difficult to differentiate this by auscultation alone. At such times, maneuvers are done which alter the flow and help distinguish the mechanism of the murmur. In general, maneuvers which decrease forward flow will decrease ejection murmurs, while those that increase forward flow will increase them. The reverse is true of regurgitant murmurs, although such changes are more difficult to discern. The outflow murmur of hypertrophic obstructive cardiomyopathy (HCM) is unique, and increases with maneuvers which decrease left ventricular volume or increase ventricular contractility. It is decreased with maneuvers which increase vascular resistance. (see section on HCM for further detail) Following are a few of the maneuvers and their responses: aortic stenosis HOCM mitral regurgitation hand grip reduced reduced increased post PVC increased increased unchanged standing reduced increased reduced squatting reduced reduced increased valsalva reduced increased reduced Additional information, including the assessment of severity, will be provided in the section covering valvular disorders. While systolic murmurs may occur in the absence of cardiac pathology, ie a flow murmur due to increased blood flow during exercise or pregnancy, diastolic murmurs always indicate the presence of cardiac valvular pathology.


3. ELECTROCARDIOGRAPHY BACKGROUND Electrical activity of the heart was first recorded in 1887, when a single lead electrocardiogram was published by Augustus Waller. However, it was William Einthoven who pursued its development and is recognized as the pioneer of electrocardiography. He coined the term “elektrokardiogramm (EKG)”, labeled the waveforms P, Q, R, S, T, U and developed the three bipolar leads still used and known as Einthoven’s triangle. In 1944, Franklin Wilson added the precordial unipolar leads, and the electrocardiogram as we know it today was completed. Despite its age, relative simplicity and the development of many new technologies, the electrocardiogram (ECG) is still extremely useful. It is the cornerstone to recognizing acute ischemia and dysrhythmias (abnormal heart rhythms). It also provides insight into anatomic alterations such as hypertrophy, electrolyte imbalances and medication toxicities. ANATOMY and ELECTROPHYSIOLOGY The basis of the electrocardiogram (ECG) is the summation of the depolarization and repolarization of the myocardium. This produces a large enough current that it can be recorded from the surface of the body. Recall that each myocardial cell maintains an electrical gradient at rest, - 90 mV, relative to the exterior. This is accomplished by sodium pumps in the cell membrane which maintain a higher concentration of negative ions within the cell. With electrical activation, there is a reversal of this gradient to a + 30 mV. This portion of the electrical action potential is referred to as depolarization. The sodium pumps then restore the cell to its usual polarity, referred to as repolarization. This electrical process spreads quickly from cell to cell, forming an electrical wavefront. The ECG records this electrical wavefront as it moves through the entire heart. This movement does not occur at a uniform speed in all cardiac tissues, allowing different components of this electrical wavefront to be temporally distinguished. Furthermore the eccentric anatomical shape of the heart ensures that the wavefront has an overall direction in space. It should be noted that if such an electrical wavefront were to spread simultaneously across a sphere, there would be no detectable signal on a standard surface ECG. The electrical wavefront produces an electromechanical reaction, contraction of the myocardium. In order to optimize the function of the four interdependent muscle pumps which make up the heart, two atria and two ventricles, there is an electrical system which carries the electrical stimulus to the chambers and stimulates them to contract in sequence. It consists of the sinoatrial (SA) node, interatrial and internodal tracts, the atrioventricular (AV) node, bundle of His, right and left bundle branches, and the Purkinje fibers.

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It is essential to the understanding of the ECG to appreciate that each of these different components of the specialized conduction system has a different set of electrical properties. The SA node is the dominant pacemaker of the heart. That is because its rate of intrinsic electrical discharge is higher than that of any other cardiac tissue. It is responsive to changes in the autonomic nervous system - leading to the expected increase in heart rate with exercise, stress and the decrease at rest. Conduction of the electrical impulse through the atria is relatively slow, due to the relative lack of specialized fast conducting fibres. However conduction is even slower through the AV node, allowing completion of atrial contraction and ventricular filling prior to initiating ventricular contraction. An important property of the AV node is “decremental conduction”. Essentially this is a protective mechanism, so that as impulses arrive with increasing frequency from the atria, conduction through the AV node slows. Therefore even in the setting of a very rapid atrial dysrhythmia, the ventricles are protected from extremely rapid electrical stimulation. The His-Pukinje fibres are highly specialized fast conducting fibres. This allows the majority of the ventricular myocardium to receive the electrical impulse at a similar time - leading to a coordinated ventricular contraction. Away from these fibres the myocardium conducts relatively slowly. The normal cardiac cycle or rhythm begins in the sinoatrial (SA) node which is located roughly at the junction of the superior vena cava and the right atrium. The electrical impulse is carried thru both atria by the interatrial tracts, and recollected at the atrioventricular (AV) node, which is located at the posterior portion of the junction of the interatrial and interventricular septa. The muscle mass of the atria is large enough to produce the first ECG waveform, the P wave. The first portion of the P wave is produced by right atrial depolarizaion, and the second portion by left atrial depolarization. It is a small, low frequency waveform, reflecting the small mass of muscle tissue being depolarized. The atrial repolarization waveform is not seen, as it is covered or masked by the ventricular waveform. The impulse then traverses the slow conducting AV node. This event is electrically silent on the standard surface ECG, and leads to the interval between the P wave and the QRS complex on the ECG. As the impulse leaves the AV node and enters the Bundle of His, conduction velocities become very rapid. Ventricular depolarization begins on the left side of the interventricular septum, and first spreads across the septum, producing a small waveform. It then spreads thru the right and left bundle branches and Purkinje system anteriorly along the septal walls and anterior free walls, then follows the free walls posteriorly. Depolarization proceeds from the endocardium to the epicardium. This produces large, high frequency wave forms referred to collectively as the QRS complex. The speed of these events is reflected by the very short duration of the entire QRS complex in normal individuals. Ventricular repolarization proceeds in the opposite direction of depolarization, thereby producing a waveform in the same direction as depolarization. It produces a lower frequency waveform, the T wave. These events do not use the specialized conduction system, and are hence considerably slower.

ollowing the T wave, a U wave is sometimes seen. Its origin and significance are uncertain.

mponents of the ECG. he following is a listing of the deflections and intervals most often measured and used:

F The typical sequence of electrical events, as seen on the surface ECG, is shown in the diagram. There is both a standard nomenclature and an expected normal appearance and timing of the various coT

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• P wave atrial depolarization • QRS complex ventricular depolarization • T wave ventricular repolarization

the interval from the beginning of atrial depolarization - or P wave - to the beginning of the QRS complex, reflecting the time taken for the impulse to

• PR interval

traverse the atria, AV node, and

• PR segment e P wave

• ST segment en the end of the QRS

• QT interval

f ventricular depolarization and

• RR interval QRS complexes; ie: one complete cardiac cycle

omponents of the QRS complex also have a specific nomenclature as follows:

eflection is NEGATIVE

llow an R wave •

b) r (lower case) if smaller than first positive deflection

ASICS of ELECTROCARDIOGRAPHY

y from a lead, it produces a egative or downward deflection.

Lea

e location when determining the electrical axis of the heart.

Lea

es electrical windows 30 degrees from the bipolar leads.

Bundle of His the isoelectric line between the end of th

and the beginning of the QRS complex the isoelectric line betwe

complex and the T wave the interval from the beginning of the QRS

complex to the end fo the T wave, representing total duration orepolarization the interval between two consecutive

The QRS complex has a variety of configurations, due both to its appearance from different locations of the chest wall and to pathologic alteration. The c

• Q wave - the first deflection, only if this d• R wave - the first POSITIVE deflection • S wave - the first negative deflection to fo

R` wave - the second positive deflection: a) R (upper case) if larger than first positive deflection

B In order to derive clinically useful information, the electrical activity is recorded from twelve different locations. Six locations or leads, referred to as the limb leads, are recorded in the frontal plane, and six, referred to as the precordial or chest leads, are recorded in the horizontal plane. EacaVL, and aVF comprise the limb leads, while V1 thru V6 comprise the precordial leads. When the electrical wavefront is moving toward a lead, it produces a positive or upright deflection, and when moving awa

h is labeled according to location: I, II, III, aVR,

n

ds I, II and III are bipolar limb leads, each recorded as the electrical difference between a negative lead and a positive lead. Lead I is recorded with a negative lead on the right shoulder and a positive lead on the left shoulder, lead II with a negative lead on the right shoulder and a positive lead on the left leg, and lead III with a negative lead on the left shoulder and a positive lead on the left leg. These three leads form an equilateral triangle with 60 degree angles, and are the first leads created by Einthoven. They are still often referred to as Einthoven’s triangle. The right shoulder lead is the zero (0) degre

ds aVR, aVL and aVF are the augmented unipolar limb leads. They are recorded as the difference between the electrode of name, ie left arm (aVL) and the mean of the other two leads. This produc

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n an axis, from just to the right side of the sternum to the left midaxillary line. They are unipolar.

he magnitude and direction of the voltage signal recorded on the ECG is dependent on the direction of the net

In situation (a) the net cardiac vector is parallel

The precordial leads are positioned across the chest, more or less o

Tvector of cardiac depolarization in relation to the direction of the lead.

This is best illustrated using Lead I as an example. One can think of the signal actually generated on the ECG as the “shadow” of the cardiac vector on the lead. So:

to Lead I and moving from -ve to +ve, so the full magnitude and

direction of the electrical vector is recorded. However in (b) the vector is at a 45° to the lead, resulting in the reduced voltage seen on the ECG. When the vector is perpendicular to the lead (c) NO signal is seen on the ECG. Lastly (d), if the cardiac vector is in the opposing direction the signal will be seen as -ve on the ECG.

Figure: Schematic illustration of the “Frontal Plane” leads. Figure: Schematic illustration of the “Horizontal Plane” leads.

Cardiac vector

“Shadow”Lead I

ECG“signal”

+

(a) (b) (c) (d)

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By convention, these twelve leads are recorded with a strip chart recorder in clusters of three. It is standardized, such that 1 mV produces a 10 mm deflection on the Y axis, and the paper speed is 25 mm per second (X axis). The paper is marked with a grid, like graph paper, with small 1 mm boxes representing .04 seconds (40msec), and large 5 mm boxes representing .20 seconds (200 msec). At the top of the paper there are slash marks every 3 seconds.

Figure: This is a NORMAL 12 LEAD ECG. A rhythm strip (Lead II) is shown on the bottom line.

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ECG INTERPRETATION In order to read or interpret an electrocardiogram, it must be reviewed systematically. This remains an important skill, despite the advent of computer-assisted analysis. Such analysis is frequently incorrect! There are five areas or aspects to be reviewed:

1. heart rate 2. heart rhythm 3. intervals 4. axis 5. morphology, or pattern, of the complexes

HEART RATE The determination of heart rate is clinically very useful. The normal rate is 60 - 100 beats per minute, reflecting the balance between the effects of the sympathetic and parasympathetic nervous systems on the SA node. A rate outside this is abnormal if a patient is at rest, and is a sign that they have developed a dysrhythmia, or may be hemodynamically unstable. The heart rate may also be used as an indicator of the adequacy of treatment or medication dosage. There are two commonly used methods to calculate the heart rate:

1. if the rhythm is regular, find a QRS complex that is aligned with a heavy line on the ECG paper. Count the number of large or heavy lined boxes (5mm) to the next QRS complex ie 3, 4, 5, etc. Divide that number into 300 to determine the heart rate. The QRS often lies somewhat between the heavy boxes, and the rate calculation is adjusted by estimating the fraction of that distance. For example, if the QRS is 4 and a half boxes away, then the rate is halfway between 60 and 75 bpm, ie 67 or 68 bpm.

2. if the rhythm is quite irregular, simply count the number of QRS or cardiac cycles in 6 seconds (30 large boxes) and multiply by 10.

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HEART RHYTHM Determination of the heart rhythm is probably the most challenging aspect of ECG interpretation, and occasionally the rhythm cannot be determined from surface recordings alone. This discussion will therefore cover only an approach to ascertaining the underlying electrical rhythm, and the recognition of common dysrhythmias. In order to identify the heart rhythm, one must know the definitions of the various rhythms, and then methodically analyze the surface ECG as follows:

• calculate the ventricular rate, and atrial rate, if different: normally the same • look for association of a P wave with each QRS: dissociation suggests AV block or ventricular dysrhythmia • assess the regularity of the rhythm: normally regular; irregularity suggests dysrhythmia • measure the QRS width: widened QRS suggests ventricular rhythm • evaluate the P wave morphology: abnormal P wave suggests origin outside the sinus node

After analysis of the ECG, one usually starts by identifying the rhythm as one of the following: sinus rhythm, supraventricular dysrhythmia or ventricular dysrhythmia. Within each of these broad categories are a number of more specific dysrhythmias. Following are the definitions of most of the common dysrhythmias.

A. Sinus rhythms:

normal sinus rhythm:

Figure: Sinus rhythm. Rate is 56, indicating a sinus bradycardia

60 - 100 bpm one P wave with each QRS regular QRS width usually normal normal P wave configuration

sinus bradycardia: < 60 bpm one P wave with each QRS regular QRS width usually normal normal P wave configuration

sinus tachycardia: > 100 bpm one P wave with each QRS regular QRS width usually normal normal P wave

Figure: sinus tachycardia sinus arrhythmia: (usually caused by vagal inhibition during inspiration)

usually 60 - 100 bpm one P wave with each QRS

Figure: Sinus arrhythmia

irregular, cycling with respiration QRS width usually normal normal P waves

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B. Supraventricular dysrhythmias:

premature atrial contraction (PAC): single, early beat arising from an area of the atrium outside the SA node.

may occur at any heart rate one P wave with each QRS causes an irregular rhythm QRS usually narrow, but may widen or be “aberrant” P wave usually different from sinus P wave

The P wave responsible for the premature beat may “masked” by the T wave of the preceeding beat. The impulse generated by a PAC will depolarize the SA node. Therefore the underlying sinus rhythm will be “reset”, leading to a delay prior to the next normal P wave and QRS complex.

Figure: An example of a PAC (arrow).

atrial tachycardia:

usually 100 - 180 bpm one P wave with each QRS

regular QRS usually narrow, but may be “aberrant” at faster rates (see section E below) P wave morphology is usually different from the sinus P wave

Figure: An example of atrial tachycardia. Note that it is indistinguishable from a sinus tachycardia (on the surface ECG).

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atrial flutter: QRS rate variable, always suspect flutter if the rate is consistently close to 150 bpm atrial rate is a multiple of the ventricular rate (2X, 3X), and approximates 300 bpm rhythm usually regular, unless there is varying block (conduction). The degree of “block” is determined by the conduction properties of the AV node and His bundle QRS usually narrow flutter (F) waves present, often “sawtoothed” in appearance - seen best in the “inferior leads” (II, III, AVF)

Figure: Typical Atrial Flutter, with a 2:1 block

Figure: Atrial flutter. Carotid Sinus Massage (CSM) results in increased AV block, due to increased va

gal tone

atrial fibrillation: QRS rate is variable no recognizable or organized atrial activity seen rhythm is irregular and without any discernible pattern QRS usually narrow

no recognizable P waves; there may be an irregular, wavy baseline - which can occasionally give the misleading appearance of a P wave.

Figure: Atrial fibrillation with a rapid ventricular response

premature junctional contraction (PJC): single, early beat arising from the AV junction

may occur at any heart rate one J wave with each QRS produces an irregular rhythm QRS usually narrow

J wave often hidden in QRS; if seen, inverted in lead II (a J wave is essentially an impulse conducted backwards - or “retrograde” - from the AV junction into the atria, and therefore represents some degree of retrograde atrial conduction)

Figure 1

Figure: The arrows indicate PJC’s

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junctional tachycardia:

QRS rate > 100 bpm if visible (frequently it is not), J wave associated with each QRS regular rhythm QRS usually narrow if visible, J wave inverted in lead II

Figure: A junctional tachycardia - note the absence of P waves

Reentrant rhythms (see Syllabus Section D for a complete discussion): Rapid - rate usually >180

Predominantly narrow QRS complex Regular “Retrograde” P waves may be seen immediately after the QRS

Figure: An example of a “reentrant” SVT - probably AV nodal reentrant tachycardia. Note also that ST segment changes are common at such a high heart rate - even in patients with normal coronary arteries

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C. Ventricular dysrhythmias

premature ventricular contraction (PVC): An abnormal electrical impulse that arises in the ventricular

myocardium may occur at any heart rate

no associated P wave produces an irregular rhythm

QRS is widened, > 0.12 seconds and bizarre in appearance, due to the lack of use of the specialized fast conducting fibres. Unlike the PAC, there is usually no effect on the SA node, which continues its intrinsic rate. There will be a delay prior to the next P wave/QRS complex, and the interval between the normal QRS complexes before and after the PVC should be twice the expected R-R interval - termed a ‘compensatory pause”. The “missing” P wave usually falls within the PVC complex, and is usually not seen on the surface ECG.

Figure: Multiple PVCs. The “compensatory pause” is well illustrated.

ventricular tachycardia (VT) : Most VT arises in diseased myocardium in the left or right ventricles. > 100 bpm no associated P waves usually regular QRS widened >0.12s may appear bizarre.

P waves (unassociated) may or may not be visible. If P waves are visible, the hallmark of VT is the lack of any link between the P waves and wide QRS complexes (called AV dissociation).

ventricular fibrillation (VF) :

no definable individual QRS complexes are seen a rapid and chaotic pattern is seen

no discernible atrial activity rhythm irregular

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D. Escape rhythms All portions of the conduction system have the intrinsic ability to generate a rhythm, albeit usually at a slower rate than the SA node. Therefore, if the sinus node fails to provide an adequate rhythm or complete block occurs at the AV node, a lower order rhythm will develop, called an escape rhythm.

Junctional Escape rhythm: Arising from the AV node rate range variable, but usually in the

40’s P waves usually not seen rhythm regular QRS usually narrow

Ventricular Escape rhythm: rate range variable, but usually in the 30’s P waves may be seen.

These may be slower than escape rhythm if there is severe sinus node disease, or faster if there is AV block alone. The P waves are not associated with the QRS

rhythm regular QRS wide

Figure: Narrow complex “junctional escape” rhythm.

Figure: Complete Heart Block with a wide complex ventricular escape rhythm

E. Aberration vs. Ectopy

The vast majority of the time, a wide QRS tachycardia will be ventricular tachycardia. However, if disease is present in the ventricular conduction system, it may not be able to conduct a rapid supraventricular tachycardia normally. This will cause widening of the QRS complex, and appear similar to ventricular tachycardia. A number of observations have been made which will help differentiate “SVT with abberration” from “VT”, however, sometimes the surface ECG interpretation will not be conclusive. In those circumstances, electrophysiologic studies may be necessary to guide treatment. The following observations on the surface ECG favor a ventricular origin:

• the tachycardia is initiated by a PVC • tachycardia beats resemble morphology of single PVCs, if present • atrioventricular dissociation present(non conducted P waves present, slower rate) • fusion beats present (beats of atrial & ventricular origin, sharing morphologies) • very wide tachycardia beats, QRS > 140 msec • extreme axis deviation, “northwest quadrant” (-90 to -180 degrees) • all precordial leads concordant, ie all neg or all positive • if present, R > r` in lead V1 (left rabbit ear taller than right)

Additional pathophysiologic and clinical information regarding dysrhythmias may be found in SECTION D of your syllabus.

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INTERVALS Intervals are usually measured in lead II, as it most often approximates the atrial and ventricular electrical vectors, providing well seen waveforms. Three intervals are routinely measured: PR - atrial depolarization and conduction thru the AV node and Bundle of His the PR interval is measured from the onset of the P wave to the onset of the QRS normal value is 120 - 200 msec, and is due mainly to passage thru the AV node A shortened PR interval suggests the presence of a congenital “bypass tract” (alos called an “accessory

pathway”) This allows the electrical impulse to avoid the slower AV nodal conduction.

a lengthened PR interval suggests that disease, intense vagal stimulation or medication toxicity is affecting the AV node QRS - ventricular depolarization the QRS is measured from the onset of the QRS to its termination normal value is 60 -100 msec prolongation suggests that disease or medication toxicity is affecting one of the bundles or purkinje system of the ventricles QT/QTc - ventricular depolarization and repolarization the QT interval is measured from the onset of the QRS to the end of the T wave normal value varies with the heart rate, shortening with faster rates and lengthening with slower rates the QT interval is normally < half the RR interval (distance from QRS to QRS) the Bazett formula is used to calculate the QTc (corrected QT), adjusting for the heart rate (QT/square root of the RR interval) normal QTc is gender specific:

• men 390 msec • women 440 msec

the QTc may be lengthened with electrolyte imbalance, especially hypokalemia, and with antiarrhythmic medications With the determination of these intervals, abnormalities of conduction through the AV node and ventricular conduction system can be identified. Conduction through the AV node may be either slowed or blocked, continuously or intermittently. In contrast, conduction through the ventricular electrical system is only slowed, but unfortunately is referred to as “block”. Atrioventricular (AV) Block- there are three degrees of AV block, ranging from a slight delay in conduction thru the node, to intermittently blocked beats, to complete absence of conduction from the atria to the ventricles. They are classified as follows:

1. First Degree AV Block- prolongation of the PR interval (>200msecs), with one QRS following each P wave

Figure: First Degree AV block. The PR interval is 280ms.

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2. Second Degree AV Block, type I (often referred to as Mobitz type I or Wenckebach block)- gradual prolongation of the PR interval, until a beat is not conducted, leaving a pause. The next P wave is conducted, and the PR interval shortens, often to normal. There will typically be a pattern, such as three conducted P waves and one nonconducted P wave - as seen below. This is often a temporary condition, and is seen in acute inferior wall infarctions.

3. Second Degree AV Block, type II (often referred to as Mobitz type II)-

intermittent block of the P waves, with no change in the PR interval, which is usually normal. It is usually indicative of structural damage/disease of the AV node/Bundle of His, and typically progresses to complete (third degree) AV block.

4. Third Degree AV Block- the PR interval is variable, without discernible pattern, as the P waves are not conducted or related to the ventricular beats, eg the escape rhythm. The atrial rate is faster than the ventricular rate.

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Bundle Branch Blocks After leaving the Bundle of His, the electrical impulse divides, passing down the right and left bundle branches to their respective ventricles. The left bundle further divides into anterior and posterior fascicles. If disease, eg fibrosis or scarring, is present, the impulse will be conducted more slowly, causing a widening of the QRS. A bundle branch “block” is said to be present when the QRS is widened to 120 msec or more. The morphology of the QRS will also be altered, allowing identification of that portion of the conduction system which is diseased. More than one portion may be diseased. There are six recognizable blocks and they are classified as follows: Right Bundle Branch Block (RBBB) QRS widened > 120 msec rSR` or RSr` in V1 (rabbit ears) wide S in V5,V6 inverted T waves in V1-V3 normal axis

(the depolarization of the right ventricle is usually “masked” by that of the left, as the RV has only 10% of the muscle mass of the left. However in a RBBB, RV depolarization occurs late, and thus may be seen - as the widened R’ in V1 and the S in V5/V6)

Figure: Typical right bundle branch block.

Left Anterior Fascicular Block (LAFB) left axis deviation, > - 30 degrees normal QRS width absence of LVH or inferior infarct (other causes of left axis deviation) Left Posterior Fascicular Block right axis deviation, > + 90 degrees normal QRS width absence of RVH or lateral infarct (other causes of right axis deviation) This is uncommon in isolation Right Bundle Branch Block & Left Anterior Fascicular Block RBBB + left axis deviation A pattern seen frequently in patients with coronary artery disease, as left anterior descending Coronary infarction/ischemia leads to damage of this portion of the conduction system.

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Right Bundle Branch Block & Left Posterior Fasicular Block RBBB + right axis deviation

Left Bundle Branch Block (LBBB) QRS widened > 120 msec monophasic R wave in leads I, V5, and V6

Figure: A RBBB with a left anterior fascicular block.

Figure: typical LBBB

Figure: This table summarizes the ECG findings in bundle branch and other conduction blocks

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AXIS Note: Students often spend far too much time and effort learning to calculate the axis. It is perhaps one of the least useful areas of ECG analysis. The discussion on how to calculate the axis is given for completeness. The mean electrical axis of the QRS is determined for each electrocardiogram. Most of the electrical force is generated by the left ventricle, and the usual axis is in a southeasterly direction (using the right shoulder as zero), roughly in alignment with the position of the left ventricle within the chest. The axis may be “shifted to the left” with an increase in left ventricular muscle mass (left ventricular hypertrophy), loss of muscle on the right or underside of the left ventricle (inferior wall infarction), or disease in portions of the conduction system (left bundle branch block, left anterior fascicular block). The axis may be “shifted to the right” with an increase in right ventricular muscle mass (right ventricular hypertrophy), acute rise of the right ventricular pressure (with pulmonary embolus), loss of muscle on the left side of the left ventricle (lateral wall infarction), or disease in portions of the conduction system (left posterior fascicular block). The axis is normally rightward in children and adolescents, gradually shifting leftward into the normal adult range as the heart responds to the change from fetal to adult circulation.

The axis is determined using the six limb leads

comprising the frontal plane. They are spaced 30 degrees apart, and range from -30 degrees to +120 degrees using standard X and Y coordinates. The normal axis lies between -30 and +120 degrees, but most often is between 0 and +90 degrees. An axis > +120 degrees is shifted to the right, while an axis < than -30 degrees is shifted tothe left. For most clinical purposes, it is sufficient to simply determine whether the axis is normal, shifted to the right, or shifted to the left.

A quick way to determine whether the axis is normal, or shifted to the right or left, is to look at leads I and aVF. If the QRS is predominantly upright or positive in both leads, the axis is normal. If the QRS is negative in aVF and positive in I, it is shifted to the left, and if negative in I and positive in aVF, it is shifted to the right. A normal axis is illustrated below.

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To calculate a precise electrical axis requires a fuller understanding of vectorcardiography. Recall that an electrical wave front moving towards an ECG lead will produce a positive or upright signal. The amount of deflection is proportional to the force, ie muscle mass, and the angle of the wave front relative to the lead. If the wave front is moving away from the electrode, the deflection will be negative or downward. If the wave front is perpendicular to the electrode, the net force is zero or isoelectric, and will produce either no discernible deflection or equal positive and negative deflections. The easiest way to determine the actual axis is to find a limb lead that is isoelectric.

Figure: The “isoelectric” lead. The sum of the positive and negative deflections of the QRS complex will be 0.

Then locate the lead which is perpendicular to the isoelectric lead. If the QRS is upright in that lead, the axis is the same as the direction of the lead; if the QRS is inverted, theaxis is 180 degrees opposite the lead. In the ECG example above, aVF is the isoelectric lead. The perpendicular lead is I. If lead I is upright, then the axis is 0 degrees.

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MORPHOLOGY The morphology or shape of the QRS complex, ST segment and T wave, is the last element of the ECG to be evaluated. Although a variety of inferences and diagnoses may be made with analysis of the morphologies (such as electrolyte disturbances, medication toxicity, etc), it is most helpful for the detection of myocardial ischemia, infarction and hypertrophy. We will limit our discussion to the latter areas.

A. Ischemia Ischemia, or lack of oxygen, is caused by a temporary imbalance of the supply/demand of myocardial blood flow. This produces a transient depression of the ST segment. This change is generally diffuse, and does not localize the anatomic area of ischemia. After restoration of appropriate blood flow, the ST segments return to their normal baseline configuration. These changes may be used to identify patients who are having angina pectoris if the ECG is recorded during a symptomatic episode, and are also used as indicators of ischemic heart disease during stress testing (see sections A5, B3 and B4 in your syllabus).

Figure: Widespread ST segment depression consistent with ischemia.

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B. Infarction

Myocardial infarction, or injury to the myocardium, occurs when the blood supply is interrupted, or reduced to such a degree, that cellular metabolic activity cannot be maintained. Such deprivation must persist approximately 30 minutes to cause an infarction. Two types of infarctions are recognized electrocardiographically, ST elevation (STEMI) and non ST elevation (NSTEMI). The ECG pattern helps identify the underlying pathophysiology, and therefore directs therapy (see section B4 in your syllabus). The NSTEMI causes ST segment depression just as ischemia, but persists 30 minutes or more. The STEMI is entirely different, beginning as ST segment elevation, and evolving over a period of hours. The genesis of this ST elevation is complex, and is referred to as the “current of injury”. If left untreated, the ST elevation typically returns to baseline, becomes flat or isoelectric, followed by inversion of the T waves.

% V4-V6.

vation localizes to the area of infarction,

aves, or old/completed with

wing is a listing f lead groups and the region of the heart they reflect:

Leads Infarct site coronary artery

ng

right coronary artery

is present if there is >1mm of ST elevation in RV4)

myocardial infarctions. For each, determine whether they are acute or old, and etermine the anatomic location.

Pathologic Q waves develop as well, and may persist indefinitely. To be termed “pathologic”, Q waves should have a duration of 0.04s (40ms). The depth of the Q wave will depend on the overall height of the R wave in that lead. For example Q waves should have a depth of >25% of the R wave height in II, III, AVF, >10% R wave in I and >15 in Unlike ST depression, ST eleas do the subsequent Q waves. The evolutionary ECG changes of a STEMI allow one to characterize it as acute, with predominantly ST elevation, several hours old with T wave inversions and small Q wpredominantly large Q waves present. The anatomic location, and the likely associated coronary artery, is determined by identifying which leads reveal the findings of infarction. Two contiguous leads must reflect such changes. Folloo

V1, V2, V3 anteroseptal anterior descending V2, V3, V4 anterior anterior descendi V4, V5, V6 anterolateral circumflex I, aVL high lateral diagonal branch II, III, aVF inferior right coronary artery II, III, aVF, V1 inferior with associated RV infarction (in this situation check the “right sided leads” - placed on the RIGHT precordium. RV infarction Following are some examples of d

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Figure: An extensive, acute antero-lateral infarction.

Figure: An evolving Antero-lateral MI

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Figure: A typical acute inferior MI

Figure: An evolving Inferior MI

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Figure: An inferior infarction. Note the ST elevation in V1 - suggesting RV involvement.

A 12 Lead ECG using RIGHT sided precordial leads will demonstrate this RV involvment clearly - as seen in the example below.

R

R

RR

R

R

Figure: An inferior infarct complicated by RV involvement. Note the ST elevation in the RIGHT sided precordial leads.

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C. Hypertrophy The workload of the heart is increased when pumping against an increased resistance, such as hypertension or a stenotic valve. Over time, the muscle of the heart hypertrophies. Each of the affected heart chambers produces an alteration of the ECG, which allows recognition of this change(s). The following criteria have been established to identify these conditions: Left Atrial Enlargement (LAE)

bifid P wave in lead II, III or aVF, and duration > 120 msecs, or negative terminal portion of P wave in V1, 1 mm deep and 40 msec wide (1mm)

Right Atrial Enlargement (RAE)

tall P wave; (>2.5 mm) in leads II, III or aVF, or > 1.5 mm in V1 or V2

Left Ventricular Hypertrophy (LVH)

increased voltage, seen as S in V1 + R in V5 or V6 > 35mm, or R in aVL > 11mm there will often be associated LAE, ST depression in the inferolateral leads, referred to as a “strain pattern”, and left axis deviation

Figure: ECG demonstrating severe LVH, accompanied by left atrial enlargement and ST-T changes typical of “strain”

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Right

V1

STdepression in V1 and V2, and right axis deviation

Ventricular Hypertrophy (RVH) in lead V1, R>S and R>6mm, or qR inthere will often be associated RAE,

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QUICK SUMMARY Here is an overview of how to approach a standard surface 12 lead ECG. It is important to develop a method of interpretation. Relying purely on “pattern recognition” can lead to students making errors. Such pattern recognition will eventually be reliable in the hands of an experienced cardiologist - but stick to the methodology when starting out! Calculate rate: rule of 300- divide 300 by the number of large boxes between R waves, or six second method- number of RR intervals in six seconds X 10 Determine rhythm: note the rate, normal 60 - 100 bpm, if slower, bradycardia ?sinus or escape rhythm if faster, tachycardia ?supraventricular (narrow QRS), or ventricular (wide QRS) ? 150 bpm, think atrial flutter look for association of a QRS with each P wave, if not- if sinus rate > ventricular rate, ? AV block if sinus rate < ventricular rate, ? ventricular tachycardia (wide QRS) regular or irregular if irregular, ?premature beats, sinus arrhythmia, atrial fibrillation, AV block measure width of QRS if wide, ventricular - or an underlying bundle branch block note P wave morphology in lead II if upright, normal PR interval, sinus short PR interval, atrial dysrhythmia or WPW if negative, junctional rhythm ? sawtoothed (atrial flutter), ? wavy, indistinct (atrial fibrillation) Measure intervals PR normal is 120-200 msec if long, ? 1st degree AV block if short, atrial dysrhythmia or WPW QRS normal is 60 - 100 msec if wide, ? bundle branch block rabbit ears in V1- RBBB monophasic R in V6- LBBB ? ventricular rhythm QT normal is ½ the preceding RR interval QTc in men 390 msec QTc in women 440 msec Determine axis if QRS upright in leads I and aVF, axis normal if QRS upright in lead I and negative in aVF, left axis deviation ? LVH, LAFB, inferior wall MI if QRS negative in lead I and upright in aVF, right axis deviation ? RVH, LPFB, lateral wall MI or find the isoelectric lead- axis is 90 degrees to the lead Morphology ? ST depression, if during chest pain symptoms, think ischemia if no symptoms, ? secondary to hypertrophy or bundle branch block

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? ST elevation, if during chest pain symptoms, think STEMI: ? anatomic location, involved artery if no symptoms, ? recent infarction, or ventricular aneurysm ? Q waves, old infarction, ? location V1, V2, V3 anteroseptal V2, V3, V4 anterior V4, V5, V6 anterolateral I, aVL high lateral II, III, aVF inferior increased voltage in V5 or V6, think LVH (left ventricular hypertrophy) ? associated changes (left axis deviation, LAE, ST changes laterally) increased R in V1, think RVH (right ventricular hypertrophy) ? associated changes (right axis deviation, RAE, ST changes in V1) look at lead II, ? wide bifid P wave- LAE ? tall, peaked P wave- RAE or look at lead V1, ? large negative P wave- LAE ? upright, peaked P wave- RAE


4. NON-INVASIVE IMAGING A. ECHOCARDIOGRAPHY Echocardiography (cardiac ultrasound), is the most commonly performed cardiac imaging test. It is portable, non-invasive, inexpensive and extremely safe. Echocardiography can provide important information in these broad areas:

1. Cardiac anatomy - chamber sizes, wall thickness, valve structure and pericardial fluid 2. Cardiac function – myocardial contraction, hemodynamics (pressure gradients etc) and valve function 3. Specific pathology - wall motion abnormalities (myocardial infarctions), masses, thrombi etc

(a) Imaging Principles

The underlying principles of echocardiographic imaging are similar to those in standard ultrasound. An understanding of the underlying physics is not necessary, but the following may help in understanding the technique. 1. High frequency (1-2MHz) sound waves are produced and focused into a ‘beam’ that is directed by the operator - using a “transducer” or probe. Tissues reflect these sound waves to varying degrees, and the returning signal is received by the probe and then analyzed to create an image. 2. In M mode a single ultrasound beam (US beam) is sent from the transducer, and the returning signals are displayed over time on a strip chart. 3. In 2D echo a US beam is swept back and forth through a defined arc (a sector), allowing a full image to be displayed in real time. 4. Doppler echo relies on the principle that the signal received from a moving object (such as blood) will have a frequency that is shifted from the original frequency sent out. The degree of this frequency shift may be analyzed to give information on the direction and speed of blood flow. This may be color coded (color doppler).

(b) Forms of echo exam

1. Transthoracic: imaging occurs with the probe on the skin surface of the chest. This is the most common imaging, but views may be limited due to the failure of US beam to transmit though bone (ribs) or hyperinflated lungs. 2. Transesophageal: a thin probe is swallowed, and imaging is performed from the esophagus. There is no rib, lung or other signal loss, and high resolution images may be seen. 3. Intravascular/Intracardiac: useful in the cath and electrophysiology labs respectively, for intra-procedural delineation of internal cardiac structures.

(c) Specific Clinical Utilization/Findings A detailed description of the abnormal echo findings in specific cardiac conditions is well beyond the scope of this syllabus. However for interest some of the key abnormalities in common conditions are listed below: 1. Ischemic Heart Disease:

• areas of reduced/absent wall thickening during systolic contraction c/w ischemia or infarction • global assessment of ventricular function - ejection fraction • thinning of the myocardium, aneurysm formation • Complications of MI - thrombus, VSD, myocardial or papillary muscle rupture

2. Cardiomyopathies: • Dilated - enlarged ventricular cavitie(s), spherical appearance, ↓ myocardial contractility • Hypertrophic - global or localized myocardial thickening, finding a “dynamic outflow gradient” • Restrictive - altered ventricular filling, ↑wall thickness, ↑LA size

3. Valvular Disease: • Mitral Stenosis: valve leaflet/chordal thickening with ↓ motion, calcification, transmitral flow ↓ on

doppler.

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• Mitral regurgitation: leaflet abnormalities (flail or prolapse) may be seen, jet of regurgitant blood on doppler

• Aortic Stenosis: calcified valve with reduced opening, high velocity outflow jet on Doppler proportionate to the valve gradient

4. Pericardial disease:

• effusion – excess fluid in the pericardial space. May also see changes of “tamponade” - the progressive compromise of cardiac output with increased fluid and pericardial pressure

Examples of echo images, in diastole (L) and systole (R)

. NUCLEAR IMAGING - PERFUSION

tection of photons produced y the decay of radioactive tracers retained in areas of myocardium in proportion to blood flow.

(a) Trac

B Imaging of the perfusion of the myocardium is a very valuable tool for the diagnosis and evaluation of coronary artery disease. Nuclear imaging is readily available, and is accurate and safe. Imaging relies on the deb

ers A variety of radioactive substances have been developed to allow imaging of myocardial perfusion. The most

m-sestamibi

nd clearance. For the tracers used, the activity imaged is known to be proportional to blood flow in the myocardium.

(b) Imag

commonly used of these are: - Technetium 99

- Thallium 201 The final myocardial concentration of a tracer, and therefore the degree of activity imaged, is a function of blood flow along with tracer extraction (related to metabolic activity in the myocardium) a

ing principles There are some important principles to bear in mind regarding myocardial nuclear perfusion imaging:

rential tracer activity between areas of

yocardium supplied with normal blood flow, and those with abnormal flow.

y artery supplying that area. owever this reduction will only be seen in a resting patient if the stenosis is >85-90%.

he flow to the abnormal bed will be unable to increas tracer activity.

categories of stress testing:

(ii) Pharow

Dobutamine - this mimics exercise by increasing the heart rate and blood flow

Using a stressor, and achieving an appropriate level of stress, stenoses of >50% may be detected.

1. The diagnosis of coronary artery disease relies on the detection of diffem 2. Blood flow to an area of myocardium will be reduced if there is a stenosis in a coronarH 3. To detect abnormal blood flow due to a stenosis less than 85%, stress testing is needed. Stress testing highlights the difference in perfusion between the normal and abnormal beds, as t

e appropriately, leading to a relative reduction inThere are 2 major (i) Exercise

macologic: - Dipyridamole/adenosine - causing coronary vasodilation and increased blood fl-

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4. Imaging is performed at rest, and immediately following stress, and the images compared. A coronary stenosis may be detected by visualizing a defect on the stress scan that is not present on the rest scan. Areas where there is

o longer perfusion - such as the scarred myocardium that may follow an infarction - will be seen as defects on both

btained, and a computer reconstruction creates the “tomographic” presentation. An example of a typical scan is shown - this one shows a large stress induced defect in the lateral wall (the territory of the circum

ing, there are defects seen when there is no coronary disease (false positives) and apparently normal perfusion when there is significant disease (false negatives). Scan results require expert interpretation, and

(c) Othe

nrest and stress scans. 5. In most labs, multiple “planar” views are o

flex coronary artery).

6. As with all imag

are not absolute.

r nuclear imaging techniques

1. Radionuclide angiography (“MUGA”). This technique uses the blood p

ool of tracer in the ventricles to age/calculate the ejection fraction of the ventricle, a measure of heart function. It is considered a highly accurate

2. Positron emission tomography. “PET”. This is used primarily as a research technique, and allows quantitation of imaging of metabolic processes.

(d) Clini

immethod of determining ejection fraction (EF% - see the Chapter “Heart Failure”)

blood flow and

cal Utilization

There are 4 major clinical areas in which perfusion scanning has been shown to be of value. At UVa the technique is

1. Diagnosis

extensively used for these applications:

of coronary artery disease - as discussed above. Nuclear imaging is an effective means of making a

. Prognosis

diagnosis, with a sensitivity and specificity of ~85%.

2 - the results of a nuclear imaging scan provide incremental prognostic information for the clinicians managing the patient. This is especially useful following myocardial infarction or other acute cardiovascular events. 3. Viability - myocardium that has poor blood flow (and therefore poor function), but remains alive may recover function if blood flow is improved (through angioplasty or bypass surgery). It is very important to distinguish this

iable” myocardium from scar prior to pursuing revascularization. Nuclear imaging has been shown to provide a “vmoderately reliable means of detecting viable tissue. 4. Acute Coronary Syndromes - a frequent diagnostic problem in the ER is determining whether a patient’s symptom

f acute chest pain represents angina/coronary artery disease. Some centers (MCV for example) use emergent uclear imaging to determine whether myocardial perfusion is normal or not during chest pain.

on

Anterior

Inferior

Lateral

Septal Lateral

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ase. It was developed using the same aging principles as “body” MRI, but has been refined to allow delineation of cardiac anatomy, tissue characteristics,

lvular function, hemodynamics and pericardial disease.

(a) Imag

C. MAGNETIC RESONANCE IMAGING

Cardiac MRI is the newest and fastest growing imaging technology for cardiac diseimcoronary artery anatomy, va

ing Principles

1. The bas

ic physics underlying cardiac MRI are the same as that for all clinical MR imaging. The signal obtained is rimarily from the hydrogen atoms in H 0. Therefore the overall % of H O in a tissue will govern its response during

. The signal is generated by the relaxation of the magnetic moment of hydrogen atoms, following application of a

. Imaging planes may be defined in 3 primary ways: coronal, transverse and saggital. However further manipulation

. Images may be either static or dynamic (“cine” imaging). The ECG is used to “gate” the images so that each

6. Contrast (gadolinium DTPA) is used to delineate vascular structures and abnormal myocardial perfusion or

(b) Clini

p 2 2the scan. 2. A high power static magnetic field is used, along with a low power variable field and radiofrequency pulses. 3radio-frequency pulse. Computer reconstruction of received signals produces a two dimensional image. 4is possible, allowing a plane to be defined anywhere. 5imaging sequence will occur at the same point in the cardiac cycle.

viability.

cal Utilization

he clinical indications for cardiac MRI are continuing to expand. At present the major uses for clinical cardiac MRI

striction arrhythmogenic right ventricular dysplasia, tumors and infiltrative diseases

ctation

. Ischemic disease- especially defining viable myocardium, and myocardial ruptures. May differentiate ischemic injury from inflammatory injury due to myocarditis.

Examples of MRI images - in diastole (L) and systole (R)

Tare: 1. Pericardial disease - especially the diagnosis of con2. Myocardial disease - especially3. Aortic diseases - dissection, aneurysm, coar4. Adult congenital heart disease 5. Tissue characterization of cardiac masses. 6. Valvular heart disease not imaged by echo. 7

LV

RV

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5. STRESS TESTING This is the most commonly performed modality of testing for the presence and/or severity of coronary artery disease. An understanding of the basic principles involved, indications/contra-indications and potential abnormal/diagnostic findings is needed. This review will not cover the technical details of performing the test itself. We will focus on the exercise stress test. Pharmacologic stressors may also be used, but exercise is preferred. Pharmacologic stressors are only used if patients are unable to exercise to an adequate workload, e.g. 85% of their age adjusted maximum heart rate. Stress testing is used primarily for four reasons: (a) To diagnose the presence of CAD

(b) To “risk stratify” the patient - that is, to assess their potential prognosis/severity of CAD after stabilization following an acute ischemic event (unstable angina/infarction), or in patients with stable symptoms of CAD. (c) To evaluate aerobic capacity after MI - prior to returning to work, participating in a rehab program or for disability assessment. (d) To evaluate a possible exercise induced arrhythmia.

BASIC PRINCIPLES:

1. Stress testing is based on the concept that changes in coronary blood flow - produced by either exercise or pharmacologic stress - will result in ischemia in the myocardial territory supplied by a stenosed coronary artery. This effective reduction in blood flow will usually produce angina, and may be confirmed/detected as ECG changes consistent with ischemia, a perfusion defect on nuclear imaging, or abnormal myocardial contraction (wall thickening) on stress echo. 2. Recall the physiology alluded to in the Nuclear Imaging discussion:

(a) Myocardial ischemia is the result of an inadequate supply of oxygen (therefore blood flow) to meet the needs of the myocardium. (b) Resting myocardium requires relatively low blood flow (low oxygen requirements), and ischemia will not occur at rest until an epicardial coronary artery stenosis is severe (>85-90%) (c) During exercise, myocardial oxygen demand is increased, and therefore an increased blood flow is needed. A stenosis of 50% may compromise the needed flow - and lead to detectable ischemia (see graph in Stable Angina discussion).

3. Exercise stress testing relies on progressively increasing the work done by a patient over a period of time, causing an increase in heart rate, blood pressure, cardiac output and myocardial oxygen demand. For a test to be diagnostically useful it is VITAL that an adequate workload be achieved. The heart rate is used as a guide to the target workload. A patient’s target heart rate is 85% of the age adjusted maximum (220-(age)). The heart rate and blood pressure may be multiplied to give a Rate - Pressure product, which is an indicator of the patient’s physiologic response. 4. Workload is measured in metabolic equivalents (METS). Increased work is usually generated by having the patient walk on a treadmill, with a pre-specified increase in speed and incline providing a series of “stages” - each with increased METS. The most commonly used protocol for treadmill exercise is the “Bruce Protocol”. 5. The patient’s response to the exercise stress is closely observed, and the ECG recorded continuously. The blood pressure is measured periodically. 6. If an imaging study is being performed, this is done at peak exercise. In the case of nuclear imaging, the tracer is injected at this time, while the images are obtained shortly thereafter. With echo, the imaging is done immediately after the patient has stepped off the treadmill. In both instances, resting images are also obtained, and a comparison is made between the resting and stress images, looking for evidence of ischemia or infarction. Ischemia is transient, and will be present with stress, but absent at rest. Infarction however, is permanent, and any detectable abnormality will be present both at rest and with stress.

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BAYESIAN THEORY:

The Theory of Bayes is not only a key part of considering a cardiac stress test, but indeed must be applied to ALL diagnostic tests in ANY field of medicine. This theory gives us insight into which patients will benefit most from having a diagnostic test performed. We will therefore cover it in some detail. Please follow the table below throughout this discussion. A: Sensitivity and Specificity

Disease State Present

TEST RESULT

+

-

a (true positive)

c (false negative)

d (true negative)

b (false positive)

Absent (i) Sensitivity - the likelihood that a patient with a given disease will have a + (positive) test a/(a+c) (ii) Specificity - the likelihood that a patient without a given disease will have a - (negative) test (d/(b+d) To be accurate and useful, a diagnostic test should have both a high sensitivity and a high specificity. Unfortunately, the sensitivity and specificity alone do NOT tell us how useful a diagnostic test might be in a specific patient population. B: Predictive value:

To understand how useful a certain test, eg: exercise stress testing, may be in accurately making a diagnosis, eg: coronary artery disease (CAD), in a specific population, we must know the prevalence of the disease in the population being tested. (i) Prevalence - all patients with the disease/ all tested patients ie: (a + c)/(a+b+c+d) (ii) Positive Predictive Value - PPV - true + test results/all + tests ie: a/(a+b) (iii) Negative Predictive Value - NPV - true - test results/all - tests ie: d/(c+d) Examples: Exercise stress testing (with high quality imaging) has a maximum sensitivity and specificity of about 90%. Let us use these assumptions to test two different populations of patients:

(a) A population of 10,000 young women age 30-35, with no risk factors for coronary heart disease. The prevalence of significant CAD in this group is about 1/1000. Therefore: true positives (a) = 9, false negatives (c) = 1, false positives (b) = 999, and true negatives (d) = 8991. This means that there are nearly 1000 false positive tests for only 9 true positives, and the PPV = 0.9% (b) A population of 10,000 middle-aged men, 50-60yo, risk factors: ↑chol, ↑BP, DM and a strong family history of CAD. The prevalence of significant CAD in this group is high - about 20% Therefore: true positives (a) = 1800, false negatives (c) = 200, false positives (b) = 800, and true negatives (d) = 7200. Now the PPV = 70%

The KEY message here is that the test is only useful if the PREVALENCE of the disease in the population being tested is relatively HIGH. Not EVERYONE will benefit from having an exercise test to screen for possible CAD!!

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CONTRAINDICATIONS TO EXERCISE STRESS TESTING:

These are included for your future use-

(a) Absolute Contraindications: Acute myocardial infarction (<2 days post), ‘high risk’ unstable angina, uncontrolled arrhythmias (eg: AFib), severe and symptomatic aortic stenosis, uncontrolled heart failure, acute pulmonary embolus, aortic dissection and inability to exercise. (b) Relative Contraindications: Severe hypertension, high-grade AV nodal block, hypertrophic cardiomyopathy with outflow obstruction (HOCM), and known left main coronary artery stenosis.

Ref: DiMarco. 3 (3:2) ABNORMAL FINDINGS: Determining whether an exercise stress test is “positive” can be complex, but there are 3 key findings that you should consider: (1) ST Segment Depression:

• The continuous ECG monitoring enables the ECG response (indicating ischemia) to be followed. 1mm (0.1mV) of horizontal or downsloping ST depression persisting 80ms after the J point (the end of the QRS complex) is the standard requirement for the diagnosis of ischemia.

• Remember that the resting ECG should ideally be normal to be able to interpret stress induced changes.

• The figure below is a summary of an exercise test, with leads V4-V6 shown. There is severe ST segment depression developing at a low work load - indicative of significant ischemia. The test is stopped and the ST segments gradually return to baseline during recovery, and are almost (but not quite) normal 12 mins after stopping the test.

(2) Hypotension:

• This is a high risk finding, and is considered to be a drop of >10mmHg while exercising • A failure to adequately increase the BP with exercise (to >120mmHg) also indicates a higher risk

test.

(3) Reproduction of Symptoms: • The reproduction of typical anginal pain, and the timing of its onset have prognostic significance

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Arrythmias are commonly seen during stress tests. VPC’s are frequently seen, and occasionally non-sustained VT or other tachyarrhythmias. These are less important in predicting CAD.

One of the most important predictors of cardiac events is the maximal exercise capacity (measured in MET workload, time on the treadmill). The Duke treadmill score (a well studied prognostic index) incorporates this key element: DTS (Duke treadmill score) = Exercise time in mins - 5x ST deviation in mm - 4x angina score (0,1,2) (0 if no angina, 1 if mild angina, 2 if test limited by angina) usual DTS range is -25 to +15 if score > 4, pt is low risk to suffer a cardiovascular event if -10 to 4, pt is moderate risk if < -10, pt is high risk. This information is provided only to illustrate the relationship of these stress test variables. You will not be expected to remember the score details.

Stress Imaging: Almost all the exercise tests performed here at UVa will have either nuclear or echo imaging in addition to the ECG. The basics of these imaging modalities are covered in the non-invasive imaging section. Imaging increases the diagnostic accuracy of the test for determining the presence of coronary disease, and also provides increased prognostic information for the clinician.

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6. CARDIAC CATHETERIZATION Cardiac catheterization is an essential tool in the diagnosis and management of cardiac patients - not only those with coronary artery disease, but also those with valvular, myopathic and pericardial disease. The first catheterization of the heart was performed in 1929, when Werner Forssmann introduced a urologic catheter into his own right atrium via a brachial vein cut down - and then climbed the stairs to the radiology department to have a confirmatory chest X-ray done!! Fortunately modern research is no longer quite as dramatic! Cardiac catheterization has TWO key components - the assessment of cardiac hemodynamics and angiography. A: HEMODYNAMICS

• Hemodynamic information is derived by recording pressure waveforms which are transmitted from cardiac chambers through hollow, fluid-filled catheters. The pressure waveform is turned into an electrical signal, displayed on a monitor and recorded.

• Right Heart Catheterization:

This provides information about the pressure waveforms in the Right Atrium, Right Ventricle and Pulmonary Arteries. It also allows the measurement of cardiac output (see below) and the “wedge pressure” - as discussed below. The procedure is usually performed with a Swan-Ganz catheter - a hollow balloon tipped flexible catheter which is primarily flow directed. The catheter may be placed through the femoral, jugular or subclavian veins. Blood may be drawn from this to assess local oxygen saturation - helpful in defining and quantifying an intracardiac “shunt”. A note on the “wedge pressure” (the pulmonary capillary wedge pressure, or PCWP). Using the S-G catheter, the balloon near the tip is inflated while the catheter is in a branch of the pulmonary artery (PA). Flow from the PA is therefore occluded in the branch, and the catheter tip records a pressure waveform that is transmitted from the LEFT atrium, through the pulmonary capillary bed. This indirect measure of left atrial pressure is a very important parameter in the assessment of left ventricular function, and valvular disease such as mitral stenosis. To the right, is a tracing showing the normal wedge pressure waveform superimposed on the directly measured left ventricular pressure waveform. The aortic waveform and ECG rhythm strip are also present. The illustrated waveforms are all normal, and should be familiar from your prior cardiac physiology studies.

• Left Heart Catheterisation: Pressures in the aorta and left ventricle are measured directly using stiffer, non-flotation (no balloon tip) catheters. As seen in the PCWP tracing above, comparison is often made to the simultaneous tracings obtained from a right heart cath, which can be very useful diagnostically.

• Cardiac Output:

This is typically measured with a right heart cath. There are 2 major methods: 1. Indicator dilution - the principle used is that an unknown volume of fluid in a container can be determined if a known volume of indicator is added and the concentration of the indicator subsequently measured (after adequate mixing). In this case cold saline is injected into the right atrium (RA), and the temperature change measured in the blood in the PA - and a curve, temperature vs time, plotted. The area under this curve is reflective of the output (the amount of blood moving from the RA to the PA), and is expressed as “liters per minute”. 2. Fick Method- a more complex method using oxygen consumption. It is seldom used today.

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B: ANGIOGRAPHY

This involves the use of radiographic contrast agents with “cine”, or movie, radiographic imaging to visualize ventricular function, coronary anatomy including lumen narrowing, intracardiac shunts, and valvular dysfunction. Imaging is performed in defined “projections” to allow all structures to be adequately visualized.

1. Ventriculography:

A large volume (30-40mL) of radio-opaque contrast is injected rapidly into the left ventricle to opacify it. This provides information regarding: (a) global function/segmental wall motion abnormalities (b) ejection fraction and left ventricular volumes (c) presence/severity of mitral regurgitation (and rarely other abn eg: a left to right ventricular shunt) A ventriculogram may appear as below: Systole Diastole 2. Coronary Angiography: This allows the lumen of individual coronary arteries to be defined, and degrees of luminal narrowing to be visualized (and quantified if necessary). A variety of catheter designs can be used to “engage” the ostia (openings in the aorta) of either the right or left coronary arteries. Once a catheter is in place, contrast is injected to opacify the artery, and a real time “cine” X ray recorded. As the coronary arteries are complex, three dimensional, branching and indeed moving structures, multiple views are taken from a variety of different angles to accurately define any degree of stenosis. Examples of right and left coronary angiograms are shown.

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Risks of Catheterization: The procedures involved are invasive and not without some risk. It is important to consider these risks prior to obtaining such procedures, particularly in the older patient (>70 yrs of age). The following data on complications of cardiac catheterization was taken from DiMarco and Crawford, Section2 (4.5) Fig 4.9

Death 0.11% MI 0.06% Neuro (CVA) 0.05% Major arrhythmia 0.31% Vascular 0.44% Allergy (contrast) 0.25%

ANGIOPLASTY. Since the first such procedure in 1977 (Andreas Gruentzig) catheter-based techniques to treat coronary artery disease have revolutionized much of the management of ischemic heart disease. It is beyond the scope of this syllabus to discuss this in any detail, but the basic technique is illustrated below:

Most patients receive “stents” today. These are essentially expandable metal scaffolds that remain within the vessel after the procedure. Most of them are coated with time released drugs which aid healing, and have been shown to improve the long term vessel patency rates after a procedure, allowing more complex lesions to be angioplastied with greater safety. The principle of “stenting” is shown:

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ADDITIONAL CATHETER BASED TECHNIQUES Stenotic valvular lesions, especially mitral stenosis, can be treated with large balloon catheters, separating the scarred leaflets and restoring moderately good function to the valves. Recently, a clip has been developed which can “clip” the leaflets of regurgitant mitral valves, narrowing the orifice and reducing the degree of regurgitation. Artificial valves are being tested which can be inserted with catheters to treat aortic stenosis. Atrial and ventricular septal defects can be closed with umbrella-like devices delivered by catheter as well. It is anticipated that many additional interventional devices will be developed, gradually offering less invasive, safer alternatives to surgical therapies currently being used.

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SECTION B

ATHEROSCLEROTIC CARDIOVASCULAR DISEASE

- - 61


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1. ATHEROSCLEROTIC CARDIOVASCULAR DISEASE PATHOPHYSIOLOGY Cardiovascular disease (CVD) is the number one cause of death in developed countries (National Center for Health Statistics), and will soon be the number one cause worldwide. In the United States alone, approximately one million deaths are attributable to CVD each year. Breakdown by involved organ system reveals:

• cardiac 78% • cerebral 16% • vascular 4% • other 2%

Atherosclerosis is the underlying etiology in 99% of all ischemic heart disease. It is a diffuse disease of medium and large arteries, and begins quite early in life. During the Korean war, postmortem examinations of American soldiers revealed the presence of atherosclerosis in the majority of them, including teenagers. It is now appreciated that atherosclerosis begins in early childhood. Cholesterol is found in the atherosclerotic plaque, and its effect upon the arterial wall is integral to the development of atherosclerosis. Cholesterol is transported in the bloodstream as lipoproteins, complexes of cholesterol, triglyceride, phospholipid and apolipoprotein. They differ by lipid content, size, density and protein. Currently recognized lipoproteins include :

• low density lipoprotein, LDL • intermediate density lipoprotein, IDL • very low density lipoprotein, VLDL • lipoprotein (a), LP(a) • high density lipoprotein, HDL

Their atherogenicity varies, with LDL and LP(a) being most atherogenic, VLDL and IDL being intermediate, and HDL being anti atherogenic, transporting cholesterol in tissues back to the liver.

e intimal fibromuscular hyperplasia pathognomonic of

therosclerosis.

ages. In addition to dividing, these cells in the lipid core can die, leasing their lipid contents into the extracellular space. (Harrisons 15th Ed,

Current evidence suggests that atherosclerosis begins with injury to the endothelial lining, resulting in structural and/or functional impairment, leading to increased permeability. Lipoproteins, especially LDL, enter the vascular wall where they are oxidized. Adhesion molecules, intercellular (ICAM) and vascular cell (VCAM), are activated, binding monocytes to the endothelial wall. The monocytes migrate into the vascular wall and convert to macrophages. The macrophages ingest lipoproteins present, forming foam cells. During this process, a number of substances are released, including growth factors, chemotactins and proteases. These result in the migration and proliferation of smooth muscle cells and fibroblasts, producingtha Figure 1: Formation of the fibrous cap and lipid core. As the fatty streak evolves into a more complicated atherosclerotic lesion, smooth-muscle cells accumulate within the expanding intima and the amount of extracellular matrix increases. The fibrous cap, formed of extracellular matrix elaborated by the smooth-muscle cells in the intima, characteristically overlies a lipid core filled with macrophreFig 241-1F)

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Atherosclerosis typically occurs in individuals with risk factors, which predispose to its development. While the presence of one risk factor may increase the liklihood of developing atherosclerosis only minimally, the presence of additional risk factors increases the liklihood exponentially. Scoring systems developed by the Framingham investigators and the National Cholesterol Education Panel (NCEP) make it possible to predict the liklihood that a patient with risk factors will suffer a clinical event, such as a heart attack, over the next 10 years. Such information is used to direct the use of treatments to revent such events, and to prevent and/or reduce the atherosclerotic burden.

The majo clude: ia

d. smoking habit

The majo age 50

f. age/gender, male age >45, female age > 55

Less si include:

h. sedentary lifestyle

tors which may prove to be equivalent to the major factors listed above, including:

esity, hypertension, low HDL cholesterol, elevated triglycerides and

insulin resistance.

emodynamically significant, eg it limits blood flow under conditions of increased flow, such as exercise, and causes angina.

does not always remain stable. It may crack or fissure, exposing/releasing materials which start the rombotic cascade -

festation of coronary atherosclerosis. (Harrisons , Fig 241-2E)

p

r treatable risk factors ina. hyperlipidemb. diabetes c. hypertension

r untreatable, or inherited risk factors, include:

e. family history, onset of clinical disease before

gnificant risk factors

g. obesity

There are several emerging risk fac i. homocysteinemia

j. chronic infection/inflammation, detected as an elevated CRP (C-reactive protein) k. metabolic syndrome, a combination of ob

Atherosclerosis is a slowly progressive process. Initially, the accumulating atheroma distends the vessel wall outward, and produces no symptoms or other clinical manifestations. When the external elastic membrane reaches its limit of distention, the growing atheroma begins to encroach upon the vessel lumen. If the lumen becomes narrowed 75% or more, the lesion is h Atherosclerotic plaqueth

Figure 2: Plaque rupture with a propagated, occlusive thrombus can cause acute myocardial infarction. When a stable, occlusive thrombus forms in a coronary artery, the consequences depend on the degree of existing collateral vessels. In a patient with chronic multivessel, occlusive coronary artery disease, collateral channels have usually formed. In such circumstances, even a total arterial occlusion may not lead to myocardial infarction, or may produce an unexpectedly modest or a non-Q-wave infarct because of collateral flow. In the patient with less advanced disease and without substantial stenotic lesions to provide a stimulus to collateral vessel formation, sudden plaque rupture and arterial occlusion commonly produce Q wave infarction. These are the types of patients who may present with myocardial infarction or sudden death as a first mani15th Ed

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leading to acute occlusion of the vessel and myocardial infarction or unstable angina, eg an acute coronary syndrome.

haracteristics of the plaque have been identified which increase the likelihood of rupture. These include:

d T lymphocytes

• increased neovascularization

e rise to an elevation of e CRP level, and a persistent smoking habit, markedly increase the risk of plaque rupture as well.

C

• large lipid core • thin fibrous cap • increased density of macrophages an• reduced smooth muscle cell density

In addition to plaque characteristics, the presence of inflammation in the vessel wall, which may givth

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2. TREATMENT AND PREVENTION OF ATHEROSCLEROSIS Atherosclerosis is an insidious disease which progresses over several decades before leading to clinically recognized symptoms or events. Unfortunately, approximately 50% of patients present with a myocardial infarction or sudden death as their first symptom, the remainder presenting with more stable syndromes, such as angina or heart failure. Our challenge then, is to identify patients with atherosclerosis prior to a clinical event, who would benefit from preventive treatment. As discussed previously, risk factors have been identified which cause and/or contribute to the development of atherosclerosis. Thus, when evaluating patients either with possible or known cardiovascular disease, each risk factor should be carefully looked at. It is clinically helpful to break the risk factors into three groups:

1. Unmodifiable • gender • age • family history, genetic

2. Modifiable with lifestyle changes

• smoking habit • sedentary lifestyle • obesity

3. Modifiable with lifestyle changes and pharmacotherapy

• hyperlipidemia • hypertension • diabetes/insulin resistance • metabolic syndrome • inflammation

Each risk factor contributes, with a gradient proportionate to its severity. However, the presence of multiple risk factors increases risk exponentially. For patients without apparent atherosclerosis, it is possible to derive a global risk using scoring systems, the most well known of which is the Framingham Risk Score. It is especially important in patients who are disease-free, eg: when considering primary preventive therapy, that the risk/benefit ratio of therapy be balanced against the global risk that the patient will develop atherosclerosis if left untreated. Treatment carries a risk of adverse reaction to medications, often requires significant changes in lifestyle, and incurs a financial burden. It must therefore be proven that such treatment is cost effective, and ultimately saves lives. The Framingham Risk Score is based upon a large data base begun nearly 60 years ago. Using age, gender, total cholesterol, HDL cholesterol, systolic pressure and smoking history (any smoking in past month), a global risk is calculated for the occurrence of hard cardiovascular events (CV death or MI) over the next 10 years. Patients are assigned to one of three levels of risk: low (<10%), intermediate (10-20%) and high (>20%). Patients at high risk would be advised to make healthy lifestyle changes and to take medications to treat their risk factors to goal, while those at low risk would be educated regarding healthy lifestyles. Available data is less clear regarding an approach to the intermediate risk group. A number of noninvasive studies have been developed to help address the intermediate risk group. Examples include ultrasound of the carotid arteries to measure thickening of the intima, CT scanning of the coronary arteries to measure the degree of calcium deposits, and CT angios of the coronary arteries. Each study is designed to detect subclinical atherosclerosis. Using the approach above, the following groups of patients can be identified:

• low risk • intermediate risk without evidence of atherosclerosis • intermediate risk with evidence of subclinical atherosclerosis • high risk • clinically apparent atherosclerosis (old MI, angina, vascular disease, etc.)

In addition to these groups, patients with diabetes mellitus and chronic renal insuffiency (creatinine >2.4) suffer cardiovascular events at the same rate as patients with known coronary artery disease, and are therefore considered “risk equivalents” to patients with clinically apparent atherosclerosis.

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The American Heart Association has developed treatment guidelines, based upon numerous clinical trials, for the prevention and treatment of atherosclerosis. Treatment is divided into two large categories: PRIMARY PREVENTION- for those without evidence of atherosclerosis and at low to intermediate global risk SECONDARY PREVENTION- for those with subclinical disease, clinically apparent disease, and risk equivalents Below is a summary of these guidelines. A. Primary Prevention Therapy The treatment of patients without recognized atherosclerosis and at low-intermediate global risk 1. LIFESTYLE CHANGES

• Smoking Complete cessation No exposure to environmental tobacco smoke • Diet Advocate a healthy diet with a variey of fruits, vegetables, grains, lowfat dairy products, fish, legumes, poultry, and lean meats. • Weight management Body mass index (BMI) 18.5-24.9 kg/m2 Waist circumference: men <40 inches, women <35 inches (measured at the pelvic crest) • Physical activity Advocate 30 minutes, 7 days a week

2. BLOOD PRESSURE CONTROL

• Goal: <140/90 mm hg <130/80 mm hg if heart failure present

3. LIPID MANAGEMENT

The primary target is LDL cholesterol, with the following goals:

For 1 risk factor, the goal is LDL cholesterol < 160 mg/dl

For 2 or more risk factors (10 year global risk <20%) the goal is LDL cholesterol < 130 mg/dl

A secondary target for patients with triglycerides >200 mg/dl is non-HDL-C (total cholesterol –HDL cholesterol). The non-HDL-C goal is 30 mg/dl higher than the respective goals above. Other targets for treatment include: Triglycerides > 150 mg/dl HDL-C < 40mg/dl in men HDL-C < 50mg/dl in women 4. ASPIRIN Advocate low-dose aspirin (81-162mg/day) in patients with a global risk of 10-20%.

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B. Secondary Prevention Therapy The treatment of patients with-

• Clinical atherosclerosis (including CAD, cerebrovascular disease, peripheral vascular disease, aortic aneurysm)

• ASCVD risk equivalents (diabetes mellitus, chronic renal disease) • Subclinical atherosclerosis • Risk factors only, at high risk (global 10 yr risk > 20%)

1. LIFESTYLE CHANGES

• Smoking Complete cessation No exposure to environmental tobacco smoke • Diet Advocate a healthy diet with a variey of fruits, vegetables, grains, lowfat dairy products, fish, legumes, poultry, and lean meats. • Weight management Body mass index (BMI) 18.5-24.9 kg/m2 Waist circumference: men <40 inches, women <35 inches (measured at the pelvic crest) • Physical activity Advocate 30 minutes, 7 days a week

2. BLOOD PRESSURE CONTROL

• Goal: <140/90 mm hg <130/80 mm hg if patient has diabetes, chonic renal disease or heart failure (preferred drug classes include beta blockers and/or ACE inhibitors)

3. LIPID MANAGEMENT

• Primary goal: LDL-C < 100 mg/dl (preferred medication class is statins) For highest risk patients, a reasonable LDL-C goal is < 70 mg/dl • Secondary target for patients with triglycerides >200 mg/dl: non-HDL-C (total cholesterol –HDL cholesterol) < 130 mg/dl (if statins inadequate, additional medications include niacin and fibrates)

4. DIABETES MANAGEMENT

• Goal: HbA1c < 7% 5. ANTIPLATELET AGENTS

• Aspirin 81-162mg daily indefinitely • Aspirin plus clopidogrel 75mg daily for 1 year after an acute coronary syndrome and/or coronary stent

6. RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM BLOCKERS • Ace inhibitors- indefinitely in patients with hypertension, diabetes, renal disease, or heart failure with ejection fraction <40% • Angiotensin receptor blockers- as above for patients intolerant of ACE inhibitors • Aldosterone blockers- indefinitely in patients with heart failure and ejection fraction < 40%

7. BETA BLOCKERS

• Indefinitely in patients with an acute coronary syndrome and/or reduced left ventricular function

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3. STABLE ANGINA Stable angina pectoris is the presenting symptom in approximately one half of patients with coronary artery disease seeking medical evaluation. It is defined as:

• chest pain/discomfort c/w ischemia occurring for more than 3 weeks (considered unstable if onset within past 3 weeks) occurring only with physical activity and/or significant emotional distress lasting for only a few minutes

1. PATHOPHYSIOLOGY

In patients with stable angina, one or more coronary arteries is narrowed by atherosclerotic plaque. Once the narrowing reduces the diameter of the vessel >75%, the artery is limited in its ability to increase blood flow to match the demands of increased cardiac work. Cardiac work is increased with exercise or other stresses which increase the heart rate and blood pressure. The inability to match the need for additional oxygen leads to a mismatch of supply/demand, producing ischemia, and angina. The ischemic threshold is defined as the heart rate × blood pressure “product” at which ischemia occurs. It provides insight as to the severity of disease, eg a low product indicates severe disease/tight narrowing, and can also be followed serially to assess progression/regression of disease. It is not affected by a change in physical conditioning.

• Differential Diagnosis

Other cardiac conditions which may cause ischemia include:

o valvular disease, especially aortic stenosis Percent Stenosis Diameter

Cor

onar

y Bl

ood

Flow

0 20 40 60 80 100

Hyperemia: Response to

•exercise•pharm. stress

Normal: •resting

Onset of ischemia –flow fails to meet demand

Onset of ischemia

o hypertrophic cardiomyopathy (HOCM) o hypertensive heart disease o pulmonary hypertension o coronary artery spasm

2. EVALUATION

i. A careful history and physical examination is essential. The symptoms must be characterized, risk factors assessed, and physical findings of atherosclerosis or alternate etiologies sought (see previous section regarding chest pain evaluation). Of these elements, the patient’s description of their symptoms is the most helpful, and should allow one to conclude whether the patient is of low, intermediate or high likelihood to be experiencing symptoms of angina pectoris. The severity of symptoms of stable angina may be classified using the New York Heart Association Classification - which has 4 levels:

Class 1: Angina with prolonged exertion No limit to normal activity Class 2: Angina walking >2 blocks Slight limit to normal activity Class 3: Angina walking <2 blocks Moderate limit to normal activity Class 4: Angina at rest or with minimal exertion Severe limitation

ii. Electrocardiogram- obtain if a non cardiac etiology is not apparent

iii. Chest x-ray- obtain if findings of non coronary heart disease or pulmonary disease are present


iv. Laboratory- obtain a lipid panel and fasting glucose to complete the risk factor assessment, and a hemoglobin if shortness of breath is part of the symptom complex

v. Stress testing- stress testing is most helpful DIAGNOSTICALLY in the group of patients felt to be of intermediate

likelihood to have ischemic heart disease. It is unhelpful in patients of low likelihood to have ischemic disease, due to the high number of false positive studies. In patients of high likelihood to have ischemic disease, stress testing is done to RISK STRATIFY them, that is, to identify patients at high risk of fatal myocardidal infarction (see below), who will benefit from therapeutic interventions. Indicators of high risk/ poor prognosis include:

• poor aerobic capacity (less than 3.5 Mets; equivalent to walking up 1 flight of stairs) • low ischemic threshold (maximum heart rate < 120 bpm) • drop in blood pressure (normally the systolic pressure rises with exercise) • extensive ischemia by ECG, nuclear scan or echo • reduced ventricular function by scan or echo Please review the section on stress testing for further details.

3. INITIAL MANAGEMENT

i. Studies have demonstrated that four types of medications provide a mortality benefit in most patients with

recognized coronary artery disease. Therefore, all coronary patients should be tried and maintained on them when indicated. They include:

• Aspirin • Statin (HMG CoA-reductase inhibitor) • Beta blocker • ACE inhibitor

Additional medications, such as nitrates and calcium channel blockers, BUT NOT short acting dihydropyridines, may be added if necessary for relief of symptoms.

ii. All patients should keep short acting nitroglycerin with them for use in the event of unprovoked angina. They should be instructed to take one nitro tablet, and if their angina is not substantially improved or resolved, they are to call 911 for assistance. They may use additional nitroglycerin every 5 minutes until assistance arrives.

4. FURTHER EVALUATION AND MANAGEMENT

i. Periodic reassessment of symptom control, risk factor control and possible disease progression is necessary.

ii. If risk stratification reveals a patient to be at LOW risk to sustain a myocardial infarction or other complications of coronary disease, eg has a good prognosis, and symptoms are adequately controlled, continuation of pharmacologic therapy is appropriate, as controlled trials have demonstrated equivalent or better outcomes when compared to a strategy of revascularization. Coronary angiography is not routinely indicated. However, if symptoms are not adequately controlled despite appropriate pharmacologic therapy, coronary angiography should be considered, and if suitable anatomy found, revascularization performed for symptomatic benefit.

iii. If risk stratification reveals a patient to be at MODERATE/HIGH risk, eg a poorer prognosis, coronary

angiography should be performed, and if suitable anatomy found, revascularization recommended.

iv. Revascularization may be performed percutaneously, eg with catheters, or surgically.

• Percutaneous therapy has the advantage of minimal morbidity and a quick recovery, eg return to normal activities in a few days. With the use of drug eluting stents, restenosis (hyperplasia in the treated segment) occurs in only 2-3% of treated lesions. However, not all lesions can be reached or treated effectively percutaneously.

• Surgery often provides more complete revascularization, and therefore better relief of symptoms, but

requires several months of recuperation and carries a significant operative risk. In general then, surgery is reserved for patients whose anatomy is not suitable for effective percutaneous therapy. A special case is disease of the left main coronary artery, for which surgery is the preferred treatment.

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4. ACUTE CORONARY SYNDROMES Acute coronary syndromes include:

1. unstable angina (UA) 2. non ST segment elevation myocardial infarction (NSTEMI) 3. ST segment elevation myocardial infarction (STEMI)

ACUTE CORONARY SYNDROME

No ST Elevation ST ElevationST Elevation

Unstable AnginaUnstable Angina NQMI QwMIMyocardial InfarctionNQMI QwMI

Myocardial Infarction

NSTEMINSTEMI

The pathophysiology and initial clinical presentation of UA and NSTEMI are similar. However, their clinical course, evaluation and treatment are quite different. Therefore, we will divide this discussion into two components, UA/NSTEMI and STEMI. A. UA/NSTEMI

1. Pathophysiology In contrast to stable angina, ischemia usually occurs in UA/NSTEMI due to the sudden reduction of blood supply. This occurs for one of the following reasons:

i. non-occlusive thrombus on atherosclerotic plaque ii. coronary spasm iii. progressive plaque growth or intimal hyperplasia iv. reduced blood flow, blood pressure or oxygen content in blood (anemia/hypoxemia)

Of these, the formation of non-occlusive thrombus upon underlying atherosclerotic plaque is the cause in the vast majority of patients. Thrombus formation is stimulated by rupture of the plaque. This typically occurs in the earlier stages of plaque formation, before it has become hardened or calcified. Such lesions have usually not advanced sufficiently to be hemodynamically significant, that is, to cause exertional angina. Hence, the onset of UA/NSTEMI is the first symptom of coronary disease for many patients. Pathologic features which predispose plaque to rupture include:

• large lipid core • thin fibrous cap • high concentration of inflammatory cells

With rupture, the release of lipid and cellular material stimulates the cascade of thrombus formation.

2. Clinical Presentation Patients present with a chest pain syndrome c/w ischemic symptoms - see the chest pain section for further details. To be classified as an acute coronary syndrome (ACS), one of the following must have occurred: 1. rest angina angina at rest, especially if lasting > 20 minutes 2. new onset angina angina starting within the past 3 weeks 3. increased angina in a patient with known stable angina, an abrupt change in pattern, with angina

occurring during minimal activities of daily living, or lasting much longer than previously

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3. Initial Evaluation A careful, expeditious history and physical examination, focusing on:

• description, characteristics of the chest pain • past history of heart disease, especially coronary disease • previous cardiovascular evaluations • risk factors for atherosclerosis • evidence of congestive heart failure (CHF) • evidence of atherosclerotic disease in other areas of the vasculature

An ECG, obtained within 10 minutes of presentation is critical, and is at the center of the ACS evaluation and management algorithm. Findings may include:

• normal ECG • transient ST depression of at least 0.5 mm in two contiguous leads (unstable angina/NSTEMI group) • elevation of the ST segment (STEMI group-discussed in the following section)

ECG taken during chest pain, showing

ST depression in precordial leads V2-V6, I & aVL, consistent with

acute UA or NSTEMI

Laboratory work, including the cardiac specific marker, troponin. Laboratory results will not be available to assist with the initial management, but will separate the UA/NSTEMI patients into their respective groups later, eg if troponin elevated, NSTEMI, if normal, unstable angina.

4. Initial Management

Patients are treated initially to relieve their symptoms and prevent progression to an ST elevation myocardial infarction (STEMI). Recommended therapy includes:

i. hospitalization ii. bedrest with continuous ECG monitoring iii. supplemental oxygen, if dyspneic or oxygen saturation < 90% iv. nitroglycerine, sublingually followed by intravenous infusion if symptoms persist v. beta blocker, intravenous followed by oral vi. morphine sulfate, intravenously, if symptoms persist vii. ACE inhibitor, if hypertension persists viii. oral antiplatelet therapy

• aspirin • clopidogrel, loading dose and daily maintenance dose • if aspirin allergic/sensitive, clopidogrel alone

ix. antithrombin therapy • unfractionated heparin, or • fractionated (LMWH)

x. platelet GP IIb/IIIa inhibitor, if symptoms persist and catheterization/percutaneous intervention planned

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5. Further Evaluation and Management

i. If symptoms persist despite initial treatment efforts, cardiac catheterization should be performed emergently to define the problem, and if appropriate, revascularization undertaken percutaneously or surgically.

ii. If symptoms abate, further evaluation should be undertaken during the incident hospitalization, as these

patients have a high, 15-25%, incidence of recurrent ACS or death within the next 30 days. Patients at moderate/high risk should undergo cardiac catheterization. This includes patients with:

recurrent ischemic symptoms while on therapy elevated troponin or other markers of myocardial necrosis dynamic ECG changes at presentation (new/transient ST segment depression) reduced left ventricular function, ejection fraction < 40% clinical evidence of congestive failure during chest pain hemodynamic instability, eg hypotension rhythm instability, eg sustained ventricular tachycardia/fibrillation percutaneous intervention within the past year prior coronary artery bypass graft (CABG) surgery, especially if > 5 years ago

In the absence of these markers, patients are risk stratified with stress testing. If high risk findings (see pg 72) occur during stress testing, then cardiac catheterization should be considered. If no high risk findings occur, patients may be treated pharmacologically. Initial pharmacological therapy should include aspirin, clopidogrel, beta blockers, ACE inhibitors and statins. Close follow-up is important, to evaluate patients’ response to treatment and return to their normal activities and work. All patients, whether treated pharmacologically or with revascularization, should be evaluated and treated as outlined in the section on secondary prevention.

B. STEMI These are patients presenting with ischemic symptoms and at least 1.0 mm of ST segment elevation in two or more anatomically contiguous ECG leads, ECG evidence of a true posterior infarction, or a new left bundle branch block (LBBB).

1. Pathophysiology

As with UA/NSTEMI, the inciting event in more than 90% of patients is plaque rupture with resultant thrombus formation. However, with STEMI patients, there is complete occlusion of the coronary artery, leading to myocardial necrosis. Animal studies have demonstrated that 85% of the myocardial necrosis occurs within the first three hours of occlusion. Therefore, rapid, effective treatment is necessary if one is to limit the extent of infarction and subsequent complications.

2. Clinical Presentation Patients present with the same ischemic symptoms outlined previously. However, they often appear to be in more distress, with diaphoresis, shortness of breath, nausea, or vomiting.

3. Initial Evaluation

As outlined under UA/NSTEMI. It is very important to determine the time of symptom onset, eg duration of pain. ECG showing ST

elevation in II, III and AVF, V5 and V6

consistent with an acute inferolateral STEMI. Note the “reciprocal” ST

depression in V1, V2. The dominant R wave

in V2 suggests posterior involvement

as well

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4. Initial Management

be diagnosed and a definitive eatment strategy begun within 30 minutes of presentation to a medical facility.

orphine sulfate, and heparin. If the blood pressure is stable, a beta blocker is given as well.

STEMI’s are a medical emergency! Every minute the coronary artery is closed, myocardium is irreversibly destroyed. Both short and long term mortality are directly related to the amount of myocardium lost. It is therefore a national goal, that all patients presenting with a possible STEMI tr As outlined under UA/NSTEMI, patients are initially administered oxygen, aspirin, clopidogrel, nitroglycerine,m If symptoms do not completely resolve with these initial measures in 10-15 minutes, then reperfusion therapy, ie: therapy to open the artery and restore blood flow, should be recommended to nearly all patients. There are two approaches to reperfusion, pharmacologic (thrombolysis) and mechanical (percutaneous with balloon atheters and stents). c

Thrombolytic therapy, ie the infusion of medications such as tenecteplase (TNK) to dissolve the thrombus, is the most often used therapy, due to its general availability in almost all hospitals in the United States. It is most effective when given early after the onset of symptoms, especially within the first 1-2 hours. After 3 hours, the response to thrombolysis is <50%, as the thrombus has become more organized, and is increasingly resistant to pharmacologic therapy. Bleeding, especially intracranial hemorrhage, which occurs in 0.5-1% of patients, is the

ajor risk, and is more likely to occur in the elderly (age >75).

dications for thrombolytic therapy are as follows:

myocardial infarction

mptoms less than 12 hours to presentation, ideally < 3 hours

• absence of contraindications

o thrombolysis include:

r trauma (especially involving the head), or CVA

previous intracranial hemorrhage

m In

• symptoms consistent with an acute• clear evidence of STEMI by ECG • onset of sy• age < 75

Contraindications t

• age > 75 • blood pressure < 180/110 mmHg • recent surgery, majo• bleeding diathesis •

Primary percutaneous angioplasty is equivalent to thrombolytic therapy during the first 3 hours of myocardial infarction, and is the preferred reperfusion strategy if symptoms have persisted for 3 or more hours. However due to its physical and programmatic requirements, ie a cath lab with experienced operators, it is currently available to only 20-30% of patients presenting to hospitals in the United States with STEMI’s. Patients in hospitals without cardiac catheterization facilities may be transferred to tertiary hospitals for percutaneous therapy, provided this can be accomplished within one hour. Further time delay mitigates the superiority of percutaneous therapy, and therefore, thrombolytic therapy would be preferable if transport is expected to exceed one hour. Other patients to consider transporting for percutaneous therapy would include those who are high risk candidates for thrombolytic therapy (increased age, recent surgery, bleeding condition, etc), failure of

rombolytic therapy, and patients who have developed cardiogenic shock (respond poorly to thrombolysis).

ken directly or transferred to medical centers with heart centers able to provide 24 X 7 percutaneous therapy.

5.

th Both approaches have resulted in major reductions in the mortality of myocardial infarction, now as low as 5 - 6%. However, studies have demonstrated that the best results are obtained if hospitals select one approach for their STEMI pts, speeding the decision-making process, and simplifying the coordination of the care team, facilities needed, etc. There is an effort to organize geographic regions to maximize the number of patientsta Further Evaluation and Management Following initial therapy, patients are admitted to a coronary care unit (CCU) where they are carefully monitored

r complications of their infarction. These may include: fo

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i. dysrhythmia, especially ventricular tachycardia and fibrillation re

mechanical complications, ie myocardial rupture, acute mitral regurgitation (papillary muscle disruption)

factors are fully evaluated and treated according to the secondary prevention guidelines previously

ations at this time include:

s tivity

• return to work

orithm

ii. congestive heart failuiii. cardiogenic shock iv.

Patients’ riskdiscussed. Additional important consider

• patient education • emotional support • life style modification• return to full ac

ACC/AHA Alg s for management of ACS:

No recurrent pain;Neg follow-up studies

Nondiagnostic ECGNormal serum cardiac markers

ObserveFollow-up at 4-8 hours: ECG, cardiac markers

Neg: nonischemicdiscomfort;low-risk UA/NSTEMI

YESNO

ST and/or T wave changesOngoing pain

+ cardiac markersHemodynamic abnormalities

Recurrent ischemic pain orEMI follow

sconfirmed

+ UA/NST -up studiesDiagnosi of UA/NSTEMI

ADMIT+ UA/NSTEMI confirmed

STE?

Evaluatefor

Reperfusion

Stress study to provoke ischemia prior to discharge

or as outpatient

Outpatient follow-up

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5. AORTIC DISEASES The aorta is the largest blood vessel in the body, carrying blood from the left ventricle to the entire systemic circulation. It measures three centimeters in its proximal portion, and gradually tapers to approximately two centimeters in the abdomen. It is normally flexible or pulsatile, absorbing the bolus of blood from the left ventricle in systole, and recoiling during ventricular diastole. Due to these characteristics, it is prone to aneurysm formation, dissection or tearing, and atherosclerosis. A. AORTIC ANEURYSM

1. Pathophysiology Aneurysms occur after the wall of the aorta has been weakened. Processes causing this include:

• atherosclerosis, most common • cystic medial necrosis, Marfan’s, with degeneration of the collagen/elastin of

the media, especially in the ascending aorta • infection, including syphilis, tuberculosis, and bacterial (mycotic) • giant cell arteritis • trauma

Once weakened, the aneurysmal process begins, and continues by virtue of the Law of LaPlace (wall stress = pressure x radius). Aneurysms are classified as fusiform or saccular.

• Fusiform aneurysms involve the entire circumference of the artery, and are usually atherosclerotic • Saccular aneurysms are an outpouching of a portion of the wall and are more often non atherosclerotic.

They most commonly occur in the abdominal portion of the aorta, below the renal arteries, with the ascending aorta being the next most frequently involved portion. With increasing size, there is increased risk of rupture.

2. Clinical Presentation

Most aneurysms are discovered incidentally by x-ray or CT scan and are asymptomatic. With sufficient size, they may cause symptoms by compression upon adjacent structures.

Thoracic aneurysms may cause: • chest pain • shortness of breath • cough • hoarseness • dysphagia

Abdominal aneurysms may cause: • back pain • chest pain • uncomfortable pulsation • aneurysmal pain, a sign of pending rupture

Aneurysms often have associated blood clot, which may embolize. This may cause renal insuffiency and/or the skin changes of livedo reticularis. Rupture usually occurs in previously asymptomatic patients, who present with severe pain in the area of rupture, and are hypotensive. This is a surgical emergency.

CT angio of an aortic aneurysm (A)

3. Management

Once discovered, aneurysms must be sized and characterized. Thoracic aneurysms must be followed by CT scan or MRI, while abdominal aneurysms may be followed with ultrasound. Studies should be repeated every 6 - 12 months.

i. Medical therapy of atherosclerotic aneurysm includes: secondary prevention of atherosclerosis vigorous control of hypertension beta blockade, to reduce pulsatile force

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ii. Surgical therapy, or stent grafting (percutaneous) is recommended if:

• ascending thoracic aneurysm > 6.0 cm • descending thoracic aneurysm > 7.0 cm • abdominal aneurysm > 5.0 cm • aneurysm expanding > 0.5 cm per year • aneurysm causing pain or symptoms/signs of organ ischemia

B. AORTIC DISSECTION A dissection is a tear in the intima of the artery. The pulsatile flow of blood in the aorta then propogates the tear distally, separating the intima from the media of the arterial wall.

1. Predisposing Factors • age > 60 • hypertension, present in 80% of patients • cystic medial necrosis, especially in patients < 40 • male gender, 3:1 ratio • bicuspid aortic valve • coarctation of the aorta • pregnancy, 40% of dissections in women occur

during the third trimester

2. Classification • Type A dissection involves the ascending aorta,

and may also involve the descending • Type B dissection involves only the descending

aorta

Some centers use the DeBakey classification system, which breaks dissections into three types: • Type I involves both ascending and descending aorta • Type II involves only the ascending aorta • Type III involves only the descending aorta

i. Type A dissections have a high mortality rate, 60 - 75% in the first few hours, and are a surgical

emergency. The most common causes of death are: • pericardial tamponade • aortic regurgitation with heart failure and shock • rupture into the left pleural space • occlusion of a vital artery, eg carotid

ii. Type B dissections have a much reduced mortality rate, and may often be managed without surgery.


Symptoms vary somewhat according to the location of the dissection, but include: • Pain- present in 70 - 80% of patients

sudden onset tearing or ripping in quality located in the anterior chest, back and/or abdomen, may migrate

• neurologic changes- present in 20 - 30% of patients parasthesia/paraplegia parasthesia/paraplegia

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- - 81

• syncope Physical findings may include:

• hypertension • shock like state- cool, clammy, diaphoretic • loss of one or more pulses • pressure differential in arms > 10 mmhg • new murmur of aortic regurgitation • pericardial friction rub • signs of CVA • New or changing bruits

4. Evaluation and Management

The presentation usually prompts a chest x-ray. Although it may be normal, helpful findings if present include: • widened mediastinum • tracheal deviation, rightward • pleural effusion, especially if isolated to the left

A definitive diagnosis must be quickly reached. One of the following studies should be emergently obtained in any patient suspected of aortic dissection:

• Transesophageal echo (TEE) • CT scan • MRI • Aortography •

The choice of study depends mostly on the stability of the patient and the availability of studies in a given situation. Each is reasonably sensitive and specific, and will reveal the entry point, extent of the dissection, and associated complications.

1. Pharmacologic therapy is initiated as soon as dissection is suspected. It includes:

beta blockade in all patients, unless hypotensive, to reduce shear stress and blood pressure, and sodium nitroprusside in all patients who are hypertensive. Both are administered intravenously.

2. If type A dissection, proceed to emergency surgery

3. If type B dissection, continue medical therapy surgical therapy indicated for unresponsive pain symptoms, or vascular compromise of a vital organ


6. PERIPHERAL VASCULAR DISEASES Although there are a number of uncommon vascular disorders which affect the peripheral arterial circulation, atherosclerotic disease accounts for the vast majority of patients encountered, especially over 40 years of age. This discussion will be limited to atherosclerotic disease. A. PATHOPHYSIOLOGY

Causation was discussed previously. While peripheral arterial disease (PAD) is a diffuse disease, severe narrowing is usually localized to segments in the medium and large sized arteries. The most frequent sites of involvement are the iliac, femoral, and popliteal arteries, which are severely diseased in 80 - 90% of symptomatic patients. In diabetics, the distal vasculature is also frequently involved. Men are affected more often than women, by a 2:1 ratio. Asymptomatic disease is present in 1 - 3% of men > age 50. Symptomatic patients have a high mortality rate due to the prevalence of associated coronary and cerebral vascular disease. The 5, 10 and 15 year mortality rates are 30, 50, and 70%, respectively, roughly 5% annually. Acute occlusion may occur due to thrombus in situ or embolism. Sources of embolism include the aorta, especially if an aneurysm is present, and the heart. Some of the possible cardiac causes include:

atrial fibrillation, fixed or paroxysmal acute myocardial infarction ventricular aneurysm endocarditis atrial myxoma (rare) prosthetic valve

B. CLINICAL PRESENTATION

The principle symptom of PAD is claudication, an aching cramp-like sensation brought on by activities which use the affected muscles. As the disease occurs most frequently in the arteries of the legs, walking is the activity most often associated with claudication. Symptoms are most often felt in the calves, but may include the buttocks and thighs. Resting the muscles provides relief in a few minutes, thus behaving just like stable angina. Very severe disease or acute occlusion may produce symptoms without activity, ie at rest. In addition to pain, the affected limb may become numb and feel cool. This generally requires urgent evaluation and treatment to preserve the limb.

C. DIFFERENTIAL DIAGNOSIS

The other major etiology to consider is “neurogenic claudication”, i.e. leg pain caused by nerve compression, usually in the spine. Spinal stenosis and sciatica are examples. Neurogenic claudication is most related to posture, and unlike vascular claudication, occurs both at rest and with activity, provided the patient is in an upright position. Relief is obtained by lying down, and stretching or straightening the spine to reduce nerve compression, rather than simply slowing one’s walking pace.

D. EVALUATION AND MANAGEMENT

1. The history should detail a description of the symptoms, the amount of activity necessary to precipitate symptoms, and the specific activities which do so. A history of other atherosclerotic disorders ie cardiac/cerebral should be sought, and a detailed assessment of atherosclerotic risk factors performed. Additionally, any history of trauma, especially affecting the spine or involved limb(s) should be obtained.

2. The physical examination focuses on signs of vascular disease. All pulses should be evaluated and assessed re

their volume or forcefulness. They are recorded on a scale of 0 to 4, with 0 being absent, 2 normal, and 4 overly forceful. They should be auscultated for bruits, and examined for aneurysm. Skin temperature, color and thickness should be assessed. Reduced circulation may cause the skin to be cool, pale, smooth and shiny. In addition there

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may be abnormal hair loss. Ischemic ulcers or gangrene may be present in advanced cases. Straight leg raising will reproduce the pain of sciatica, and therefore be a clue to the presence of neurogenic claudication.

3. The ankle/brachial index (ABI) of each limb should be measured. The brachial pressure is measured per usual, then

the ankle pressure is measured with a pressure cuff over the calf, and the posterior tibialis and dorsalis pedis systolic pressures measured. The ABI is the ratio of the respective systolic pressures. It is normally 1.0 or greater. If < 1.0, significant PAD is present, while an index < 0.6 indicates severe disease.

4. Exercise testing is very helpful. In patients with equivocal findings/symptoms, a reduction of the ABI to < 1.0 during

exercise would confirm the presence of significant obstructive disease. In addition, the exercise capacity is useful for serial monitoring of treatment. Further evaluation with doppler will help confirm the hemodynamic severity of disease and will localize the area of narrowing.

5. Angiography is generally reserved for evaluation prior to planned revascularization.

E. TREATMENT

1. Measures to prevent injury to the feet, eg properly fit, protective shoes. Support hosiery should be avoided, as they compress the arterial bed.

2. All risk factors of atherosclerosis should be vigorously treated according to the secondary prevention guidelines.

However, beta blockers may aggravate claudication, and should be used carefully, eg at lower doses than usual. 3. Vasodilators provide little if any relief of claudication symptoms. 4. A program of daily, vigorous walking for at least 30 minutes is essential, and will improve symptoms. Walking may

promote the growth of collaterals, eg new blood vessels passing about the areas of blockage. 5. Pentoxifylline is approved for treatment, reportedly working by increasing red cell deformability, and thereby,

reducing blood viscosity. 6. Cilostazol is also approved, and has antiplatelet activity as well as being a mild vasodilator. 7. Investigational studies are in progress with the use of angiogenic growth factors to promote the formation of

collateral growth. 8. If symptoms become debilitating or limb viability is threatened, then revascularization, either percutaneous or

surgical, should be considered.

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SECTION C

DISORDERS OF THE HEART

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1. HEART FAILURE This is an increasingly common diagnosis in cardiovascular medicine, but it is a syndrome, not a disease. Physiologically, heart failure is present when abnormal cardiac function is responsible for the inability of the heart to pump blood at the rate required by metabolizing tissues - or can do so only at an elevated diastolic volume/pressure. Clinically, this altered physiology leads to the heart failure syndrome, with symptoms and signs such as dyspnea, fatigue and fluid retention. Many cardiovascular disorders, such as myocardial infarction, valvular disease, hypertension, dysrhythmia, pericardial disease, or cardiomyopathy, may lead to this state of affairs. This chapter will concentrate on disorders of the MYOCARDIUM that produce this syndrome. A. PHYSIOLOGY/PATHOPHYSIOLOGY Myocardial performance (contraction) depends on cellular integrity (cellular contractility), and mechanical factors including “preload” and “afterload”. Recall Starling’s law for the heart, which defines a fundamental property of heart muscle - that the force of contraction at any given tension depends on the length (stretch) of the muscle fiber. Essential concepts are:

• Preload is the tension/pressure on the myocardial wall at the end of diastole - just prior to ventricular contraction. This is proportional to the end diastolic volume – which stretches the muscle fiber. The relationship between volume and pressure at end diastole, and the effect on overall cardiac performance is shown in the graph to the right (from Harrisons 15th Ed). This family of curves is named the Starling Curves.

• Afterload is the tension or ‘wall stress’ present after the onset of systole, or contraction of the myocardium- and is related to the arterial pressure/resistance. As arterial pressure/resistance rises, stroke volume falls - which can cause acute exacerbations of CHF in patients with failing hearts (see below).

• Contractility is also referred to as the inotropic state. When preload and afterload are constant, increasing contractility (with drugs for example) can augment the cardiac output.

Additional key terms used in discussing myocardial performance include:

• stroke volume (SV) - the amount of blood ejected with each systole • cardiac output (CO) - stroke volume(mL) x heart rate (beats per min) = CO (normal~ 5-6 L/M • end diastolic volume (EDV) – quantity of blood present in the filled ventrilce • ejection fraction (EF) - the portion of blood ejected with each systole – SV/EDV x 100 (normal 55-65%)

B. TERMINOLOGY/CONCEPTS IN CLINICAL SYNDROMES

1. Systolic Dysfunction vs Diastolic Dysfunction: • Systolic failure is a disorder of impaired myocardial contractility - leading to a reduced ejection fraction and a

reduced stroke volume. As we will see below this is associated with an elevated end diastolic left ventricular volume and pressure.

• Diastolic failure is a disorder of impaired myocardial relaxation leading to reduced filling in diastole and an elevated diastolic pressure. The ejection fraction may be normal or reduced.

2. High output vs Low output:

• Heart failure of myocardial causes results in a low output state - where the overall cardiac output is less than normally required.

• A less common cause of heart failure is a high output state - where the demands of the systemic circulation are very high - leading to an inadequate cardiac output - even when that output is actually greater than

normally required. Conditions that may cause this state include severe chronic anemia, Pagets disease, sepsis, a peripheral arteriovenous (AV) fistula, and “beri-beri” heart (rarely seen in the USA today).

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3. Acute vs Chronic:

• Heart failure may be very sudden in onset - for example in the setting of a myocardial infarction, or may be a chronic syndrome. Patients will frequently present with acute exacerbations of chronic heart failure.

C. ADAPTIVE MECHANISMS The failing heart has a variety of mechanisms of adaptation to attempt to maintain an adequate cardiac output to meet the body’s needs. Many of these adaptations are deleterious in the long term, and are the focus for therapeutic interventions.

1. Increasing preload. As we have seen earlier, according to the Frank-Starling mechanism, the end diastolic volume (a surrogate for cardiac muscle fiber length - or PRELOAD) - is related to the stroke volume of the ventricle. Therefore increasing the preload improves cardiac output (up to a point). However this leads to a greater end-diastolic pressure and the resultant increased wall stress is ultimately detrimental to myocardial function.

2. Increasing myocyte size - hypertrophy. This can improve contractility, but leads to diminished relaxation and diastolic dysfunction.

3. Neuro-hormonal modification: a. Renin-angiotensin-aldosterone: these hormones

are increased as cardiac output falls, responding to a decrease in renal blood flow. This is an attempt by the kidneys to maintain glomerular filtration through peripheral vasoconstriction (increasing blood pressure), and the retention of salt and water (increasing vascular volume). However, the peripheral vasoconstriction leads to increased afterload, which further impairs a failing ventricle.

b. Adrenergic - Norepinephrine levels are elevated, increasing the afterload, myocardial contractility, and heart rate in an effort to maintain cardiac output.

D. CLINICAL

1. History - can be very helpful in distinguishing heart failure from other disorders. • Dyspnea: this is the most common symptom. It is related to increased pulmonary venous and capillary

pressure, and therefore interstitial edema in the lungs, impairing oxygen exchange. Breathlessness may be classified and gives an indication of the severity of the disease (For example the NYHA (New York Heart Association) classification - I, II, III, IV - see figure on next page).

• Orthopnea: this is dyspnea which is apparent when lying supine - due to redistribution of fluid from the abdomen/peripheries to the lungs, which raises pulmonary hydrostatic pressure, causing further interstitial edema.

• “PND” - paroxysmal nocturnal dyspnea. This is severe breathlessness and coughing, which occurs after lying down for several hours, awakening patients from their sleep.

• Fatigue and weakness are prominent features in more advanced disease, due to reduced cardiac output.

2. Physical Examination • Patient may be uncomfortable, in distress, especially lying down. • Central and/or peripheral cyanosis may be present • Pulse may be low volume, and may have a pattern of alternating volumes (pulsus alternans) in severe

systolic failure. • Sinus tachycardia is often present • Jugular venous pressure may be elevated, and if not, hepatojugular reflux may be seen • An S3 or S4 may be present (not specific for CHF) • Lungs: inspiratory crackles may be heard in the lung bases, possibly with signs of pleural effusions (dullness

and decreased breath sounds). • Peripheral (dependent) edema - usually symmetric • Ascites, hepatic enlargement • Weight loss “cachexia” - in severe disease.

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NYHA CLASSIFICATION OF HEART FAILURE CLASS I: A patient with cardiovascular disease who has either no symptoms, or has no limitation of ordinary activity. They may experience symptoms, angina, dyspnea, etc. with marked exertion. CLASS II: A patient that experiences slight limitation of ordinary activity, that is, after walking more than two level blocks or climbing more than one flight of stairs. CLASS III: A patient that experiences marked limitation of ordinary activity, that is, unable to walk two level blocks or climb one flight of stairs, without experiencing cardiorespiratory symptoms. CLASS IV: Patient has symptoms at rest, which are increased with any physical activity.

3. Diagnostic tests:

• ECG - no specific findings - abnormalities may reflect the underlying cause, eg old myocardial infarction • CXR - may show cardiomegaly, interstitial edema, venous cephalization, pleural effusion • ECHO - this is the best initial study and is recommended in all patients with new heart failure symptoms • Cardiac Catheterization may assist in defining the hemodynamics of heart failure, and evaluating possible

causes such as valvular disease and coronary artery disease. Ventriculography visualizes ventricular size, and function/dysfunction.

E. ETIOLOGIES

A. Underlying pathologies :

1. Systolic dysfunction:

Coronary disease (infarction) Toxins - cocaine, alcohol Idiopathic cardiomyopathy Valvular heart disease Hypertension - post hypertrophy Infections - myocarditis

Endocrine - diabetes, thyroid disease Muscular Dystrophies Peripartum Nutritional deficiencies “Beri-beri”

2. Diastolic dysfunction:

LV Hypertrophy: May be primary (see HCM section), or more commonly secondary - from hypertension or aortic stenosis, for example.

Infiltrative - amyloid, sarcoid, hemochromatosis Restrictive disease - radiation, fibrosis

B. Exacerbating factors. As well as considering the underlying cardiac pathology, it is very important to consider the

possible reasons for an exacerbation of heart failure - especially in patients presenting to the emergency room. These include:

• Dietary indiscretion- (Na+)/fluid intake • Arrythmias • Environmental (high humidity, heat) • Anemia • Mental stress • Hypertension (esp in diastolic HF) • Infection (endocarditis, sepsis) • Pulmonary embolus • Ischemia • Poor medication adherence

• Thyrotoxicosis • Pregnancy


F. TREATMENT

The treatment goals are to decrease symptoms, prevent acute exacerbations, reduce or prevent the progression of the disease and to prolong survival. Treatment will be most effective if it can address both the underlying etiology of the heart failure, and the reasons for exacerbation.

1. NON-PHARMACOLOGIC • salt restriction (Na+) - less than 2.5g/24 hours • water restriction in severe acute CHF – less than 2 liters/24 hours • encourage regular aerobic activity in outpatients with chronic CHF • community follow-up and patient counseling are important

2. PHARMACOLOGIC

• Diuretics: remove excess salt and fluid, providing symptomatic relief. Most commonly used is furosemide (Lasix), which inhibits the Na+/K+ co-transport in the loop of Henle in the kidney. Other useful drugs include spironolactone - an antagonist of aldosterone, which may have a survival benefit and hydrochlorothiazide.

• Angiotensin converting enzyme inhibitors(ACEI): these block the conversion of angiotensin l to angiotensin II - which is a maladaptive response. Reduction of angiotensin leads to a reduction in afterload, which is beneficial for the failing heart, and may improve LV ejection fraction. These drugs are proven to improve symptoms, exercise tolerance and prolong survival.

• Angiotensin receptor blockers (ARBs): these block the action of angiotensin ll. They may be used in addition to ACEIs or in place of them, and similarly reduce symptoms, improve exercise tolerance, and prolong survival.

• Beta blockers: these block the deleterious effects of increased catecholamines on the myocardium. They have been proven to reduce mortality, and also to improve ejection fraction in some patients. Mortality is improved (in part) by reducing the incidence of arrhythmias which lead to sudden death.

• Digoxin: This is a mild positive inotrope - and the oldest drug for CHF (discovered famously by William Withering - from the Foxglove plant). It may reduce symptoms and exacerbations.

• Other: a. Vasodilators (such as a long acting nitrate + hydralazine) - may have a small benefit when used in

addition to ACEIs/ARBs. In patients unable to take either ACEIs or ARBS, and in African Americans, the combination of nitrates and hydralazine have a survival benefit.

b. Inotropes - Dobutamine, Dopamine, Milrinone - increase myocardial contractility - these are used in severe, acute exacerbations of CHF, to stabilize a critically ill patient. They are available only in intravenous form.

c. Anti-thrombotic therapy - in patients with severe systolic dysfunction, there may be a benefit to anticoagulation with Coumadin, an anti thrombin, to reduce the incidence of thromboemboli.

d. Anti-arrhythmic therapy - see below. e. Avoid negative inotropes, such as nondihydropyridine calcium channel blockers.

3. MECHANICAL • IABP - intra-aortic balloon pumping - a very temporary option used in critically ill patients, to maintain blood

pressure and to reduce afterload. • LVAD – left ventriclular assist device- a pump to create an increased cardiac output - implanted surgically -

used primarily to keep patients alive prior to cardiac transplant. • ICD - implantable cardiac defibrillators. These terminate otherwise fatal ventricular arrhythmias - VT/VF.

They have been proven to improve survival in patients with severely reduced ejection fractions (<30%). • Pacing - biventricular pacing may help severely symptomatic patients with CHF and LBBB, or dyssynchrony,

by re-establishing synchronous contraction of the left ventricle. • Transplant - for selected patients this may provide a long term option. Survival after orthotopic transplant is

approximately 85% at 1 year and 70-75% at 5 years. Integrating these numerous therapies is a challenging task. Typically a patient presenting with heart failure symptoms/signs will be initially diuresed to improve symptoms, and salt/fluid restriction begun. The most important initial drug class to begin immediately is the ACE inhibitors - as these bring a benefit to both cardiac function and survival. These are begun at relatively low doses and increased over time. Beta Blockers are begun once the patient is stable and compensated for several weeks, again at low doses and increased gradually. Regular follow-up and community and office based education are very important. These therapies form the core of treatment for all patients with heart failure.

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2. VALVULAR HEART DISEASE This section will cover the most common valvular abnormalities seen, with an emphasis on the clinical presentation, the physical exam findings, and how these relate to the underlying pathophysiology of the valve lesion in question. It will be helpful for you to review the basic anatomy of the valves, as well as the normal physiology of the cardiac cycle prior to reading this section. Lesions of left sided valves have more clinical importance than those of right sided valves - and we will therefore focus on the mitral and aortic valves. Valve lesions may be broadly divided into those that impede forward flow (stenotic), and those that permit abnormal backward flow (regurgitant). Also note that although we describe symptoms associated with each lesion, most patients with valvular lesions are asymptomatic until the hemodynamic compromise from the lesion is quite severe. A. MITRAL STENOSIS (MS) This remains an important valvular lesion despite its declining prevalence (due to the dramatic reduction in cases of rheumatic fever). Although there are other very rare causes of MS, rheumatic fever remains the major one.

1. Anatomy/Pathophysiology: The valvulitis resulting from rheumatic fever occurs primarily at the edges of the anterior and posterior leaflets. Over the following decades chronic injury/inflammation leads to fusion of the commissures, thickening of the chordae, and stiffened or even calcified valve leaflets. This leads to a restriction in the opening of the leaflets, so that the open valve area falls from 4-6cm2 to below 1.5cm2 - creating an obstruction to forward flow into the left ventricle. The effect of this anatomical obstruction is:

• an increased gradient across the mitral valve during diastolic filling of the left ventricle (LV) • a reduction in total flow, a small LV at end diastole, and a decrease in overall cardiac output (CO) • elevated pressures in the left atrium (LA), leading to a dilated LA , pulmonary hypertension and in late

stages, right ventricular (RV) failure due to the transmitted pressure in the pulmonary vessels • LA dilation leads to atrial fibrillation in many patients, which may further compromise LV filling and

reduce CO • The large LA has sluggish blood flow, predisposing to the formation of thrombus, with possible systemic

embolism (especially cerebrovascular accidents - CVA)

2. Clinical Presentation: a. Symptoms:

• Dyspnea, orthopnea, paroxysmal nocturnal dysnea • hemoptysis due to ruptured bronchial veins • if RV failure, then peripheral edema (note this is a LATE finding in MS)

b. Signs: • normal or low volume pulse, with AFib in many patients • JVP usually normal unless RV failure • Apex beat - a palpable S1 (“tapping” apex), normal position, rarely a palpable diastolic thrill • Auscultation - a loud S1 (if the leaflets are still mobile), an “opening snap”, a low pitched “rumbling”

diastolic murmur (best heard with the patient in left lateral, using the bell). If in sinus rhythm there is an accentuation of the diastolic murmur prior to the S1 (due to atrial systole)

• Note that in severe MS the S1 may be soft due to leaflet immobility, the opening snap is earlier in diastole (closer to S2), and the murmur is longer.

c. Tests: • ECG: may show AFib, “P mitrale” - a sign of LA

enlargement • CXR: Enlarged LA contour, but normal LV size,

pulmonary edema • ECHO: this is the diagnostic test of choice for

delineating the anatomy and degree of hemodynamic abnormality

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3. Management:

I. Medical a. Minimize the hemodynamic impact of the obstruction, using beta blockers to slow the heart rate and

increase the diastolic filling time, diuretics to remove excess salt and water, limit exercise, avoid pregnancy in significant lesions

b. anticoagulate, especially if AFib is present c. treat AFib with rate control or cardioversion

II. Surgical/Interventional (generally performed for the relief of symptoms) a. Valve replacement/repair b. Catheter based balloon mitral valvotomy

B. MITRAL REGURGITATION (MR) This discussion will primarily refer to chronic MR. Acute MR (in the setting of MI and papillary muscle rupture) is catastrophic, leads rapidly to cardiogenic shock, and is a surgical emergency. MR is the second most common valve lesion in the US, and results in abnormal blood flow from the LV to the LA in systole.

1. Anatomy/Pathophysiology: A variety of abnormalities of the leaflets, chordae or papillary muscles will lead to regurgitation. Hence the causes of MR include the following:

• myxomatous degeneration (associated with mitral valve prolapse - see below) • coronary disease - post MI, with tethering of the leaflets from loss of normal muscle contraction • endocarditis • spontaneous rupture of a chord • rheumatic heart disease (mixed disease - MR + MS is common) • collagen vascular disease (eg; lupus) • cardiomyopathy- dilated LV cavity and mitral anulus • Other - post trauma, post surgery Pathophysiogically MR leads to: • decreased afterload - leading initially to more complete LV emptying (with a proportion going to the low

pressure LA of course). • increased LV diastolic filling - from the large volume of regurgitant blood in the LA. This increases the

preload, and a higher stroke volume results. • overall effective CO reaching the systemic circulation may actually fall, as a substantial portion of the SV

goes to the LA, and not out into the aorta. • under these conditions (esp the increased preload) the LV gradually dilates and systolic contractile function

falls, resulting in left heart failure - and ultimately pulmonary hypertension with secondary RV failure.

2. Clinical presentation: a. Symptoms: these include dyspnea, other symptoms of heart failure - especially fatigue and exercise

intolerance due to the decreased CO b. Signs:

• a normal or sometimes high volume pulse • atrial fibrillation is common • JVP will only be elevated in right heart failure -

a late feature • Apex is laterally displaced, diffuse and

hyperdynamic • Auscultation - the S1 is soft, an S3 is common.

A pansystolic murmur is heard best at the apex, and radiates to the axilla.

c. Tests: • ECG - may be in AFib. Look for evidence of a prior MI • CXR - LA and LV enlargement, pulmonary congestion may be present • ECHO - Transthoracic echo is the test of choice (TTE). A transesophageal echo (TEE) is usually

reserved for the evaluation of possible surgical intervention, especially for consideration of repair.

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3. Management: I. Medical

a. Treat CHF symptoms with diuretics etc. b. anticoagulate if AFib is present c. treat AFib with rate control or cardioversion

II. Surgical/Interventional a. Valve replacement/repair (the latter if anatomically possible). Surgery is generally performed in

appropriate patients when there are either symptoms or evidence of LV systolic dysfunction is seen. Special case: MITRAL VALVE PROLAPSE (MVP): This results from a “floppy valve”. Valve leaflets (anterior, posterior or both) are pushed backwards (prolapse) into the LA during systole. Prolapse is usually associated with some degree of regurgitation. Pathologically the valve tissue is abnormal, with a proliferation of “myxomatous” connective tissue. The leaflets are weakened and stretch excessively, usually losing coaptation. Despite many descriptions of a “Mitral Valve Prolapse Syndrome”, this lesion is not clearly associated with atypical chest pain, palpitations or panic attacks. The lesion IS associated with bony abnormalities of the thoracic cage, including pectus excavatum, scoliosis and a straight thoracic spine. At auscultation a systolic “click” may be audible, followed by a late systolic, high pitched murmur. The click will be earlier, and the murmur louder, when the patient stands or valsalvas, which reduce the LV volume/size. C. AORTIC STENOSIS (AS) This is the most common valve lesion in the US - affecting primarily the elderly population. There are 3 important etiologies - and the age of the patient presentation may vary with the cause of the stenosis.

• senile calcific degeneration of the valve - usually presenting age>65 • rheumatic aortic valve disease - usually age 45-65 • congenital abnormalities (bicuspid valve) – usually age 40-50

1. Pathophysiology: the obstruction to left ventricular outflow produces a systolic pressure gradient between the LV and the aorta. This “pressure overload” of the LV leads to hypertrophy, as an adaptive mechanism to maintain cardiac output. Unfortunately this hypertrophy leads to:

• reduced LV compliance (diastolic filling is impaired) • increased myocardial oxygen demand • eventually late in the disease, LV systolic dysfunction occurs, and CO falls.

2. Clinical presentation:

a. Symptoms: patients are frequently asymptomatic - and may be so even when the obstruction is severe. When symptoms do occur (late) they include: • Angina - related to a mismatch between oxygen supply and demand, as 50% of patients with this do not

have epicardial coronary disease. • Syncope - especially exertional - due to reduced CO • exertional dyspnea

b. Signs: • the pulse may be low in volume (parvus), and peak late (tardus), but only in severe disease. • the apex beat is forceful, sustained, and typically slightly displaced laterally.

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• findings on auscultation depend on the severity of the valvular obstruction. As the valve becomes more stiffened, its closure (A2) becomes softer, and eventually is inaudible. Thus splitting of S2 is lost, eg, it sounds single during inspiration if stenosis is severe. With narrowing/obstruction to flow across the valve, a systolic ejection murmur is produced. The murmur becomes more harsh, more prolonged, and peaks later with progressive narrowing of the valve. The murmur typically radiates to the carotid arteries.

Tests: • ECG - will show left ventricular hypertrophy (LVH) • CXR - increased heart size due to LVH • ECHO - this is the initial diagnostic test of choice to define the degree of hemodynamic obstruction, and

the status of ventricular function. • CATH - can confirm the hemodynamics, and rule out CAD prior to surgery

3. Management:

i. Asymptomatic patients: manage their risk factors for CAD, watchful waiting ii. Symptomatic patients should be considered for valve replacement.

D. AORTIC REGURGITATION (AR) As with MR this discussion will focus on chronic AR, and not the rarer and more catastrophic acute lesion.

1. Etiology/Anatomy: • Rheumatic fever: leaflets are thickened with commissural fusion and leaflet retraction. • Endocarditis - localised leaflet destruction/perforation, vegetations • Aortic dissection • Aortic sclerosis/calcific disease (usually AS predominates, but frequently mixed AS and AR are present) • Connective tissue disease - Marfans is the best documented • Congenital - bicuspid aortic valve (only 2 functioning cusps are present) • Syphilis (tertiary) - more for historic interest

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2. Pathophysiology: • The total stroke volume is increased, but in compensated patients with chronic AR the effective CO (that

reaching the systemic circulation) is normal. The extra blood is of course regurgitating into the LV during

urgitant volume increases the LV end-diastolic volume (increased preload) and the LV gradually

hypertrophy. Severe untreated AR can lead to massively dilated and hypertrophic hearts (cor bovinum)

ion

diastole. • This reg

dilates • This in turn leads to increased myocardial wall tension, resulting in

3. Clinical presentat :

a. Symptoms: • frequently asymptomatic (until late stage disease). Decompensation results in symptoms of heart failure,

uding dyspnea and fatigue inclb. Signs:

• look for signs of systemic disease eg: Marfans • pulse is typically “collapsing” - the pulse pressure (difference between systolic and diastolic pressures) is

)

anterior

wide (also called a “water hammer pulse”• the apex is displaced and hyperdynamic • on auscultation the A2 will be soft. The

murmur is high pitched and decresendo - beginning immediately after S2 - and lasting a variable time into diastole (longer = more severe in chronic AR). A systolic ejection murmur is usually present due to increased blood flow through the valve. A rumbling mid-diastolic murmur is described (Austin Flint) due to the “shuddering” of themitral leaflet in the regurgitant jet.

• there is a long list of eponymous signs associated with AR, primarily due to the prevalence of syphilis in the 18th/19th century!! As they are all too frequently discussed we will reproduce them here for your interest - even though the majority of them are of almost NO clinical use.

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ee of LV enlargement, and status of ventricular function. It is useful for following asymptomatic patients.

c. Tests: • ECG - LVH and “strain” • CXR - a large heart is typical • ECHO - definitive diagnostic test. It also reveals severity of regurgitation, degr

4. Management:

i. Asymptomatic patients: • regular monitoring including echo to follow LV dimensions/systolic function • vasodilators - long ++ acting dihydropyridine Ca channel blockers or ACE inhibitors may slow disease

• valve replacement

. TRICUSPID VALVE DISEASE

. Tricuspid regurgitation (TR):

ilure. Other causes include tricuspid endocarditis (most often due to IV drug abuse) and congenital heart disease.

Ex

progression ii. Symptomatic patients:

E

1 This is very common. Minor degrees of TR are seen on ECHO and are considered physiologic. Moderate or severe TR is usually a result of right ventricular failure/dilatation, most often occurring as a result of severe left ventricular fa

amination findings include: • elevated JVP, with prominent V waves due to regurgitation of blood into the RA/SVC

This can be heard to increase

• an RV heave (at the left sternal border) may be present • on auscultation there is a systolic murmur at the lower left sternal border, radiating to the right

sternal border in severe cases. on inspiration, due to increased

• In severe cases there may be a pulsatile liver, ascites and peripheral edema.

2. Tricuspid Stenosis:

hink through how this might present, based on your nowledge of MS and the physiology of the right heart.

OTE: diseases of the pulmonic valve, and issues related to prosthetic heart valves will not be covered

venous return to the right heart.

Extremely rare, and due to rheumatic heart disease. Tk

N .

. ENDOCARDITIS PROPHYLAXIS

deterioration, systemic emboli, r formation of cardiac abscess. Pathogenesis involves the following circumstances:

• proliferation of the bacteria, resulting in vegetation formation

ia. for the administration of antibiotics prior to

certain procedures, in patients at high risk to develop endocarditis.

G

Valves, native and prosthetic, may become infected, a condition called endocarditis. It is quite serious, often requiring urgent/emergent surgical replacement due to overwhelming hemodynamic o

• development of thrombus on an endothelial surface • infection with bacteria transiently in the bloodstream

Although unproven, it is theoretically possible to prevent endocarditis in circumstances likely to produce bacterem Therefore, the American Heart Association has developed guidelines

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High risk patients include those with a history of:

s

ding those with shunts & conduits)

valvulopathy in transplanted hearts (patients are immunosuppressed)

alities are at such low risk, that they are no longer routinely given antibiotic prophylaxis.

d include: netration of the gingiva

• GI/GU procedures IF infection is present

s tooth iva. Therefore, maintenance of optimal dental health is important for all patients with

valvular heart disease.

• prosthetic heart valve• prior endocarditis • unrepaired CYANOTIC congenital heart defects (inclu• congenital defects repaired within the past 6 months •

Patients with other native valve abnorm

Procedures that may result in transient bacteremia for which antibiotice prophylaxis is indicate

• dental procedures involving manipulation/pe• surgeries involving infected skin or muscle

Most cases of endocarditis appear to result from random bacteremias associated with routine activities such a brushing of infected ging

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3. PERICARDIAL DISORDERS A. ANATOMY AND PHYSIOLOGY The normal pericardium is comprised of two thin layers, the inner visceral pericardium or epicardium, and the outer parietal pericardium. Each layer has a secretory serosa, while the parietal layer also has a tough fibrous layer which is attached to the sternum, great vessels and the central tendon of the diaphragm. It is innervated by the phrenic nerve, accounting for the radiation of pain symptoms. The pericardium helps anchor the heart, lubricates its surface, and participates in its hemodynamics. With inspiration and descent of the diaphragm, the parietal pericardium is stretched, lowering the intrapericardial pressure, and augmenting venous return to the heart. In conjunction with this, there is a small decrease in the arterial pressure called the pulsus paradoxus (see figure (b)), or paradoxic pulse, normally less than 10 mmHg. This occurs principally for two reasons: the pericardium limits distention of the right ventricle during augmented return, causing the interventricular septum to bow into the left ventricular cavity as the right ventricle expands, reducing left ventricular capacity (see figure (a)), and secondly, with inspiratory increase in pulmonary vascular capacity, there is a momentary reduction in filling of the left ventricle. In pericardial disorders this normal hemodynamic behavior is altered and becomes exaggerated, reducing cardiac output.

“Pulsus paradoxus”

Septal bowing

B. DISORDERS OF THE PERICARDIUM The vast majority of patients develop noneffusive pericarditis, which typically produces a small exudate, while a small number will develop effusive pericarditis, which produces varying amounts of effusion, which may cause cardiac tamponade. Rarely, pericardial constriction will occur, as a late complication of acute pericarditis. Noneffusive Pericarditis 1. Pathophysiology

The pericardium has rich vascular and lymphatic supplies, and thus may be affected by most any systemic disorder or infective/noxious agent present in the vascular or lymphatic systems. It may also become involved by direct extension from contiguous organs/structures. Because of the myriad etiologic possibilities, it is best to categorize according to pathologic process. Below is a listing in decreasing order of prevalence, likely to be seen by a primary care physician, in an outpatient setting:

• Idiopathic- mostly unidentified viral infections • Infectious- mostly identified viral infections, tbc and AIDS • Acute myocardial infarction- mostly an early inflammatory response • Chronic renal failure • Metastatic neoplasm • Connective tissue disorder- especially rheumatoid arthritis and SLE • Trauma, acute • Autoimmune- weeks following cardiac surgery or myocardial infarction • Metabolic- especially hypothyroidism • Radiation therapy- acute or chronic, as late as 20 years post radiation • Drug reaction- especially procainamide, hydralazine

In response to a pathologic process, the pericardium produces a small fibrinous exudate. Because the visceral pericardium is adherent to the myocardium, there is a small associated myocarditis which may be identified with

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serum enzymes such as troponin I. This should not be confused with myopericarditis. This term is reserved for myocarditis with congestive heart failure and a mild, associated pericarditis.


Patients typically present with chest pain. They may also feel short of breath, have painful palpitations, fever, myalgias or odynophagia. Chest pain characteristics include:

pleuritic positional, feeling better when upright sharp, oppressive retrosternal radiates to the arms, neck and/or trapezoid ridge

The symptoms must be differentiated from: pleurisy pulmonary embolus chest wall injury/inflammation aortic dissection myocardial infarction

3. Physical Examination

The cardinal physical finding of acute pericarditis is the pericardial friction rub. It is: high pitched scratchy located most often along the lower left sternal border

Classically it has 3 components (see below), produced by: atrial systole (As) ventricular systole (Vs) ventricular diastole (Vd)

If all 3 components are present, it sounds like a “choo choo train”. However, this is the case in only half of patients. Otherwise, 30% will have 2 components, 10% will have 1 component and 10% will not have an audible rub.

Other findings may include: • fever • sinus tachycardia • weakness • pallor • enlarged lymph nodes • active arthritis

Evidence of hemodynamic compromise must be sought in all patients, including: • hypotension • elevated JVP • increased pulsus paradoxus

4. Evaluation

An electrocardiogram should be obtained in all patients suspected to have pericarditis. The associated myocarditis produces changes which typically evolve thru 4 stages: Stage I present a few hours to a few days (see ECG below) diffuse ST elevation in all leads but aVr and V1 preservation of the concave T wave morphology PR segment depression, especially in the inferior leads

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Stage II present a few days return to a nearly normal EKG Stage III present a few days to a few weeks diffuse inversion of the T waves Stage IV return to normal

A chest x-ray should be obtained in all patients. This is done to measure the cardiac silhouette. If the silhouette is not enlarged, it is very unlikely that a hemodynamically significant effusion is present. Other findings suggestive of an alternative explanation of a patient’s symptoms might include:

o pneumonia o tumor, enlarged lymph nodes o enlarged aorta o pleural effusion o rib/sternal fracture

There are no specific laboratory findings. Therefore, any labs obtained should be directed by findings from the history and examination suggesting a specific etiology.

There are no echo findings specific for the diagnosis of pericarditis. Therefore, an echocardiogram should be obtained only if findings on examination or chest x-ray raise suspicion of a significant effusion.

5. Treatment

Patients need be hospitalized only if there is evidence of significant effusion. Most will respond to a several week course of NSAIDS.

Effusive Pericarditis 1. Pathophysiology

Normally, pericardial fluid is in a dynamic equilibrium. With inflammation or irritation, there is an exudative response, and increased production of transudate. Excess accumulation occurs when resorptive capacity is exceeded. This may be accentuated by partial obstruction of lymphatic drainage, leading to the development of large effusions. While the same broad range of etiologies causing noneffusive pericarditis may cause effusive pericarditis, there is a significant change in prevalence. The most common causes of effusive pericarditis include:

Metastatic neoplasm Chronic renal failure with uremia Connective tissue disorders Tuberculosis Congestive heart failure Hypothyroidism Radiation therapy

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Effusive pericarditis rarely causes chest pain. Large, chronic effusions may cause some feeling of shortness of breath, but most are detected incidentally during chest x-ray or CT. Approximately 250cc of fluid is necessary to produce recognizable enlargement of the cardiac silhouette on chest x-ray.

3. Evaluation

In contrast to noneffusive pericarditis, a benign viral infection is rarely the cause of effusive pericarditis. Therefore, a more extensive evaluation is undertaken to discover the etiology. An appropriate evaluation would include:

i. chest x-ray ii. tuberculin skin testing iii. CBC iv. chemistries v. rheumatologic panel vi. thyroid panel

The electrocardiogram seldom reveals the acute changes seen in noneffusive pericarditis. There may be a generalized reduction of voltage, and in very large effusions, electrical alternans, a several mm variation in the height of the QRS on alternate beats due to the increased to and fro movement of the heart. Electrical alternans should always raise the suspicion of tamponade. The echocardiogram is very helpful. It is sensitive for detection of fluid, allows rough quantitation of fluid volume, and serial studies will indicate change in volume. It also will detect the development of tamponade. Pericardiocentesis may be performed if the diagnosis has remained uncertain. It is most helpful in the detection of infective etiologies. Performance of a pericardial window with removal of tissue for biopsy will increase the diagnostic yield.

4. Treatment

Therapy is directed at the underlying cause. NSAIDs may be used to slow the production of transudate.

Cardiac Tamponade Tamponade is the most common, and the most dangerous complication of pericarditis. 1. Pathophysiology

Tamponade occurs with the sudden or gradual accumulation of fluid within the pericardial sac, raising the intrapericardial pressure sufficiently to compress the heart and interfere with normal filling of the heart. In an advanced stage, it is a medical emergency, producing severe hypotension. The most likely etiologies include:

Metastatic neoplasm Chest trauma Iatrogenic, post cardiac surgery and post pacemaker insertion Renal failure with uremia Aortic dissection Myocardial rupture


The principal symptom is shortness of breath. 3. Evaluation

The physical examination is very helpful. Typical findings include: tachypnea sinus tachycardia, occasionally atrial fibrillation hypotension distended JVP clear lungs pulsus paradoxus > 10 mmHg

As tamponade is an abnormal physiologic state, studies such as ECG and chest x-ray are of limited help.

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Echocardiography with doppler is the non-invasive study of choice. It will demonstrate the pericardial effusion, compression of the right heart chambers, and reduced blood flow during inspiration which produces the paradoxic pulse.

4. Treatment

Treatment requires removal of the pericardial fluid. This may be done with pericardiocentesis, at which time a right heart catheterization is usually done. This will confirm the diagnosis by demonstrating the equalization of the pulmonary capillary wedge pressure, the pulmonary artery and right ventricular diastolic pressures, and the right atrial pressure. When a second catheter is placed within the pericardial space, the pressure should equal the previous pressures. Surgical removal may also be performed, generally by creation of a window into the left pleural space.

Pericardial Constriction Constriction is a chronic complication of pericarditis. 1. Pathophysiology

Constriction is caused by heavy fibrosis and calcification of the parietal pericardium in response to previous infection/inflammation. It fuses with the visceral pericardium, obliterating the pericardial space, and adheres to the myocardium. As it thickens and stiffens, it constricts the heart during diastole, impairing venous return. The most common causes include:

idiopathic, ie unrecognized viral infection infectious, especially viral and tuberculosis post cardiac surgery post radiation


Patients present a year or more after the inciting event. Their symptoms occur slowly, insidiously, and include: dyspnea fatigue fluid accumulation They appear to be chronically ill, and a differential diagnosis includes: cirrhosis COPD mitral stenosis pulmonary hypertension, primary or secondary cardiomyopathy, restrictive

3. Evaluation The physical examination is very helpful. Findings may include:

sinus tachycardia low blood pressure elevated JVP, appears hyperdynamic with accentuated wave forms, due to a “prominent Y descent” Kussmaul’s sign- rise in JVP during inspiration clear lungs pericardial knock- sounds like a loud, high pitched S3 enlarged liver ascites pedal edema

The ECG has no specific findings, but may have low voltage and right axis deviation. The chest x-ray may reveal calcification of the pericardium. To confirm the diagnosis, the thickened pericardium must be visualized and the abnormal hemodynamics demonstrated. The pericardium may be seen with CT scan, MRI or echocardiography, especially transesophageal. Cardiac MRI is the best non-invasive modality to image the pericardium. Hemodynamics are obtained with cardiac catheterization. They include equalization of the diastolic pressures, and a right ventricular pressure contour like a “square root sign” (√). Sometimes a myocardial biopsy is done to differentiate constriction from restrictive cardiomyopathy.

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4. Treatment

Symptoms may initially be improved with diuresis, but the only therapy that will improve/correct the abnormal hemodynamics is surgical removal of the pericardium. This is a difficult operation, carrying a significant mortality, and unfortunately, does not always completely relieve symptoms due to injury of the myocardium and/or the inability to remove the entire pericardium.

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4. HYPERTROPHIC CARDIOMYOPATHY Hypertrophic cardiomyopathy (HCM) is a genetically determined disorder, defined by the presence of unexplained “hypertrophy” (increased thickness) of the myocardium. It is important to consider and exclude other illnesses that may cause secondary hypertrophy - such as hypertension or aortic stenosis. With HCM, there is no definable inciting illness. As knowledge about this disorder has progressed, terminology has evolved. You may also see this disorder called idiopathic hypertrophic subaortic stenosis (IHSS), or hypertrophic obstructive cardiomyopathy (HOCM). 1. Anatomy/Pathology

The hypertrophy is asymmetric in 2/3 of patients - affecting the septum >> the lateral and posterior walls. Microscopically, myocyte disarray is seen, rather than normal but hypertrophied cells.

2. Pathophysiology

• Ventricular function Systolic function is usually hyperdynamic, with small LV cavity dimensions. However there is reduced ventricular compliance/relaxation - and so diastolic function is abnormal.

• Dynamic outflow tract obstruction: This occurs in about ¼ of patients. During systole the mitral valve (anterior leaflet) and the subvalvular apparatus (chordae) are pulled towards the thickened septum by the Venturi effect. This “systolic anterior motion” (SAM) of the valve creates a variable degree of obstruction to left ventricular outflow. The degree of obstruction is especially dependent on left ventricular filling: less filling = a smaller cavity and more obstruction. SAM also contributes towards mitral regurgitation, which is frequently present.

3. Genetics

• Numerous mutations of genes encoding for sarcomeric proteins (such as B myosin heavy chain, 14q11) have been identified. Some mutations carry a worse prognosis.

• There is variable penetrance and phenotypic expression of these mutations

5. Clinical Features

• Most patients are asymptomatic. • Symptoms may include:

o dyspnea - due to diastolic dysfunction and associated heart failure, o presyncope/syncope - either due to outflow tract obstruction or arrhythmia o sudden death – HCM is the most commom cause of sudden death in the USA of apparently healthy young

people, especially athletes, often occurring during or immediately after exertion. Hank Gathers’s death on the basketball court is a tragic example of this. Sudden death often occurs in asymptomatic patients, and is difficult to predict.

• Physical examination findings include:

o a central arterial pulse with rapid initial upstroke followed by a sustained pulse - described as a “spike and dome” - quite different from aortic stenosis

o a prominent “a” wave seen in the JVP o a double apical impulse due to presystolic expansion of the ventricle caused by atrial contraction (atrial

gallop) and the ventricular systolic impulse. In severe obstructive cases, three impulses, the so called “triple ripple” may be felt, caused by the atrial gallop and two ventricular systolic impulses, the second occurring after outflow obstruction occurs.

o a late systolic ejection murmur at the left sternal border/apex, arising from the dynamic outflow obstruction o a holosystolic murmur at the apex may also be heard, arising from mitral regurgitation o The outflow murmur is increased by the Valsalva maneuver and by standing, both of which reduce venous

return and thereby, ventricular filling or volume, and increasing obstruction. The murmur is decreased by squatting, which increases peripheral resistance, reducing ventricular emptying, and thereby, obstruction.

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• Diagnostic testing o ECG - may demonstrate features of left ventricular hypertrophy, left atrial enlargement, and abnormal ST

segments and T waves. o ECHO - this is the key diagnostic test for confirming hypertrophy, the presence of SAM, and defining the

degree of outflow tract obstruction, eg the gradient. 6. Treatment The goals of treatment include:

• Reduction of symptoms • Improvement of ventricular compliance • Reduction of outflow obstruction • Reduction of sudden death

Symptomatic patients are generally treated with beta blockers at high doses, to reduce the heart rate, increase the diastolic filling period, reduce inotropy, reduce obstruction, and reduce arrhythmias. If beta blockade alone is inadequate, a nondihydropyridine calcium channel blocker (verapamil) may be added to further reduce inotropy. Occassionally, disopyramide is added as well, due to its negative inotropic effect. If pharmacologic therapy is inadequate, relief of the obstruction may be achieved with surgery or catheter based therapy. With surgery, a septal myotomy/myectomy is performed, that is, removal of a portion of the septum at its base. With catheters, the 1st septal perforator can be perfused with alcohol, causing a limited infarction of the base of the septum. Both approaches achieve excellent results. Patients generally will require continuation of some of their medication in order to address the nonobstructive features of their disorder. The risk of sudden death is difficult to assess, but is generally increased in patients who develop symptoms during adolescence, especially syncope. It is also increased if there is a family history of sudden death. Strenuous physical activity seems to increase the incidence, suggesting the mechanism may be increased obstruction and provocation of dysrhythmia. Therefore, all patients with HOCM are advised to forgo competitive athletics and very strenuous physical activities. Very high risk patients may be advised to consider a defibrillator. All family members should be screened for HOCM with echocardiography, and younger patients should underdo genetic counseling. Treatment is aimed at reducing symptoms by increasing ventricular relaxation and diastolic filling times (using beta blockers and calcium channel blockers), preventing sudden death (using beta blockers and in high risk patients implantable defibrillators) and reducing the degree of outflow obstruction in patients in whom this is causing severe symptoms (using beta blockers and calcium channel blockers, or mechanically either by surgical removal or catheter based ablation of a part of the upper portion of the septum).


5. ADULT CONGENITAL HEART DISEASE This chapter will provide a brief overview of some of the most common congenital abnormalities of cardiac anatomy that are seen in adults. Many of these may present for the first time in adulthood. Complex congenital disease which primarily presents in infancy or childhood will not be covered. It is also of note that the most common congenital cardiac abnormality is a bicuspid aortic valve. This was covered in the section on aortic valve disease, and will not be repeated here. 1. ATRIAL SEPTAL DEFECT (ASD) An abnormal opening in the atrial septum allowing the blood to flow from the higher pressure LA to the lower pressure RA.

1. Embryologically the septum forms in a complex fashion. Initially the septum primum grows down from the roof of the common atrium towards the atrioventricular valves. Later, perforations appear in the upper part of this septum, and these join to form the ostium secundum (OS). During this time a second ridge of tissue - the septum secundum grows down and across the atria, covering the ostium secundum. Defects in one or more of these stages create specific types of ASD - as below.

2. Classification of ASD’s is based on their location and embryological

origin: a. Ostium Secundum (OS) - due to incomplete growth of the

septum secundum, or excessive resorption of the septum primum.

b. Ostium Primum (OP) - incomplete growth of the septum primum

c. Sinus Venosus (SV) - at the junction of the SVC and the RA

3.

Pathophysiology. The septal defect leads to a shunt - which is from LA to RA. In other words there is abnormal blood flow from the left atrium into the right atrium. This leads to volume overload of the right side of the heart. A shunt is defined by the ratio of the volume of blood that passes through the lungs (QP) to the volume of blood that passes through the systemic circulation (QS). A typical ratio for an ASD might be 2:1 - in other words there is twice as much volume passing through the pulmonary circuit as through the systemic circuit. In ASD’s, this shunt can lead to right ventricular enlargement and failure. Other potential complications include paradoxical emboli (venous thrombi “thrown” into the systemic circulation thru the defect during diastole), and atrial arrythmias.

4. Clinical findings.

Most patients are asymptomatic, but common symptoms include shortness of breath and palpitations. The key physical exam finding is of a wide fixed split of the second heart sound. This is due to the longer ejection time of the increased RV volume, and therefore later closing of the pulmonic valve. There may also be a soft systolic flow murmur across the pulmonary valve (heard at the upper left sternal border), and less commonly a diastolic flow murmur across the tricuspid valve (heard at the lower left or right sternal border). The ECG usually reveals normal sinus rhythm, and has an RSR’ pattern in V1 The CXR may show an increased cardiac silhoute due to enlargement of the RA and RV, large pulmonary arteries, and a small aorta. The overall vascularity will be increased in the upper lobes of the lungs, often referred to as “shunt vascularity”). The diagnosis is typically confirmed by ECHO (TTE). The degree of shunt and overall hemodynamics may be demonstrated with cardiac catheterization if required. Cardiac MRI may also provide this information, as well as additional associated anatomic abnormalities, if present.

5. Management of ASD’s with sizable shunts (Qp/Qs > 1.5:1) is to close them - either with surgery, or with a catheter delivered device.

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2. VENTRICULAR SEPTAL DEFECT (VSD) A congenital defect of the interventricular septum that leads to shunting of blood. Note that VSD’s may also be acquired (after infarction for example). Note also that many small VSD’s in infancy will close spontaneously prior to adulthood.

1. Classification is by VSD location on the septum. This may be inlet (atrioventricular), trabecular (muscular), outlet (supracristal) and membranous - the most common (80%).

2. Pathophysiology

a. Hemodynamic significance is determined by size and location, as well as the relative pressures on either side of the defect.

b. Large VSD’s will initially have a large left to right shunt, but the shunt will decrease as the RV hypertrophies and RV and PA pressures rise to match systemic (LV) pressure. Ultimately the shunt may become right to left (Eisenmengers physiology) leading to systemic (central) cyanosis.

c. Small VSD’s maintain a large pressure difference and a small shunt.

3. Clinical. Small VSD’s may be asymptomatic., while large VSD’s will present in infancy with heart failure. Physical examination findings include a harsh pansystolic murmur heard best at the lower left sternal edge, and an S4 or S3 may be heard. Once again, the diagnosis is confirmed by ECHO or MRI. Management depends on the size of the defect and the degree of shunt. Defects may be repaired surgically or with catheter based techniques.

3. PATENT DUCTUS ARTERIOSUS (PDA) This is the persistent patency of the ductus arteriosus after birth.

1. Embryology/Pathophysiology: Recall that the ductus arteriosus develops from the 6th left aortic arch, and in the fetus is vital as a diversion of blood flow from the pulmonary to the systemic circuits (bypassing the nonfunctioning lungs). At birth the increased oxygen tension triggers closure of the ductus in normal individuals. A patent ductus will lead to a shunt from the aorta to the lower pressure pulmonary circuit, with the shunt volume depending on the diameter and length of the PDA

2. Clinical: Frequently asymptomatic, but may present with dyspnea, CHF, or become infected (endarteritis). Physical

examination may reveal a low diastolic blood pressure, a hyperkinetic apex beat, and a characteristic continuous, “machinery” murmur throughout systole and diastole. P2 will be increased. Diagnosis is made by ECHO, MRI or CATH, and surgical closure is usually recommended.

4. COARCTATION OF THE AORTA This is a localized narrowing of the thoracic aorta, and is frequently associated with other congenital defects such as a PDA, VSD or bicuspid aortic valve. Typically the narrowing is located at the previous site of ductus arteriosus insertion, just below the origin of the left subclavian artery.

1. Systemic blood flow to the lower ½ of the body may be compromised, leading to reduced renal blood flow and renally mediated hypertension. Patients are usually asymptomatic, and have upper limb hypertension. Examination will also reveal “radio-femoral delay” - the lagging of the femoral pulse relative to the radial pulse.

2. The classic CXR finding is of rib notching due to erosion of the inferior surface of the ribs by intercostal arteries

providing collateral flow to the lower part of the body. 3. Surgical repair or the placement of an endovascular stent are treatment options.

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5. TETRALOGY OF FALLOT This is the classic constellation of a VSD, pulmonary stenosis, right ventricular hypertrophy and an over-riding aorta. It will almost always present in infancy, but is an important syndrome to be familiar with, as many patients are surgically corrected and surviving into adulthood.

1. Pathophysiology: Hypoxemia and cyanosis are typical. The large VSD allows the RV and LV pressures to nearly equalize. The degree of pulmonary stenosis determines the amount of blood flow to the lungs. Increasing severity of stenosis will mean an increasing right to left shunt. “Tet spells” are severe cyanotic episodes, which occur during/after exercise when systemic vascular resistance (SVR) falls - which increases the right to left shunt. Spells may be aborted by squatting - which increases the SVR, and therefore reduces the shunt and degree of cyanosis.

2. Clinical: Physical examination findings will include cyanosis, clubbing of the fingers/toes, signs of RV enlargement (a

parasternal lift) and a single S2 (absent pulmonary closure sound, P2). A pulmonary ejection murmur will be present.

3. Diagnosis is made by ECHO or MRI and surgical management initiated if indicated. The Blalock-Taussig shunt, which links the left subclavian with the pulmonary artery to increase pulmonary blood flow, is a temporizing procedure sometimes done in infants. Total correction is the preferred operation.

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SECTION D

DISORDERS OF RHYTHM

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1. BRADYARRHYTHMIAS These are defined as heart rates that are inappropriately low for the physiological demands of the body (usually <60bpm). However pauses/conduction abnormalities that result in impairment of cardiac function are also included in this category, even if the heart rate is not <60bpm. These abnormalities may be broadly divided into disorders of the sinus node, and those involving the remainder of the conduction system. A. Sinus Node Dysfunction: 1. Anatomy/Physiology: The sinus node is a collection of specialized pacemaker cells located in the right atrium, near the

entry of the superior vena cava (SVC). The membrane potential of these cells is not stable, and becomes progressively less negative until an action potential is triggered (when the threshold is reached). The impulse generated by this action potential is then conducted out of the sinus node to the remainder of the heart. Either failure to generate this impulse, or failure to conduct it out of the sinus node may be responsible for bradyarrhythmias/pauses.

2. Etiologies: Sinus node dysfunction may occur due to:

i. Intrinsic disease: degeneration, infiltration, ischemia or inflammation ii. Extrinsic factors: autonomic nervous system changes, drugs, endocrine disorders or electrolyte abnormalites.

3. Clinical features: Symptomatic sinus node dysfunction is more common in the elderly, and is the stated reason for 50%

of pacemaker implantations in the US. It is important to remember that abnormalities on the ECG should be correlated with clinical symptoms.

Symptoms include: • Syncope/near syncope • Fatigue • Breathlessness, exercise intolerance • Dizziness

ECG Abnormalities include:

• Sinus arrest/pauses - failure to generate an action potential. This is illustrated in this ECG tracing - there is a cessation of P wave activity and a prolonged pause that is not a clear multiple of the prior sinus rate.

• Sinus node exit block - this is the failure of a generated impulse to conduct to the atrial tissue - the

resulting pause will be a multiple of the prior sinus rate, as illustrated below.

Note that in the prolonged absence of a sinus node derived rhythm, other (slower) “pacemakers” will take over. This is called an “escape rhythm”. The AV nodal cells will generate an impulse at a rate of 40-50bpm (a junctional escape) and the ventricular myocardium will pace at 25-30bpm (a ventricular escape).

4. Diagnosis: This is made with ECG monitoring, correlated with symptoms. Monitoring may be for 24 hours (a “Holter

Monitor”) or for 2-4 weeks with an “event recorder”. The latter allows the patient to trigger a recording at the time of

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symptoms - and is very helpful in making a diagnosis in a variety of arrhythmias. Invasive electrophysiology (EP) studies may provide confirmation if needed.

5. Treatment: Extrinsic factors responsible for the dysfunction should be sought and corrected if possible. For intrinsic

disease, implantation of a pacemaker is usually necessary. A pacemaker monitors the heart rhythm, and if it falls below a preset rate for any reason, the pacemaker will provide an electrical stimulus to the heart, causing it to contract. The choice of pacemakers and their settings is too complex to discuss in this syllabus.

B. Conduction System disorders. Delays in the propagation of a sinus impulse may occur throughout the conduction system of the heart - and may therefore occur at different levels in this system. 1. AV NODE

i. Anatomy/Physiology: The AV node is an oval structure of specialized muscle cells located in “Koch’s triangle” - bounded by the tricuspid valve, the membranous septum and the sinus septum - in the lower RA. Its blood supply comes from the right coronary artery (90%). Conduction through the AV node is slow - recall that the P-R interval on the surface ECG reflects the conduction time through the AV node. It is also termed “decremental” - that is the conduction becomes slower at higher heart rates - this is a protective mechanism.

ii. Pathophysiology: There are 3 types of AV conduction disorder typically classified as:

a) First Degree: this is simply a prolongation in the conduction time through the AV node, and a long PR interval (>0.2s) is seen on the ECG. This is a benign abnormality.

b) Second Degree: Some atrial impulses do not get conducted to the ventricle in a situation where they normally would be. This is further classified as:

a. Mobitz I (Wenkebach). In this case the PR interval lengthens progressively until an atrial

impulse is not conducted, as shown below. Mobitz I block is usually transient, and rarely progresses to complete heart block.

b. Mobitz 2 - there is no progressive PR lengthening, and an atrial impulse is non-conducted

without warning, as shown below. This carries a more serious risk of progressing to complete heart block than the prior disorders, and is not considered benign.

c) Third Degree: This is complete AV block - no atrial impulses are conducted to the ventricles, and an escape rhythm,usually ventricular, occurs, as shown below. It is slow, and the complexes wide.

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iii. Etiologies: a) Intrinsic: Degeneration, ischemia, inflammation b) Extrinsic: Drugs, autonomic nervous system changes, endocrine disorders

. INTRAVENTRICULAR CONDUCTION

2

i. Anatomy/Physiology: The conduction system below the AV node begins with the bundle of His, and then branches into left and right bundles. The fibers from these fan out through the respective left and right ventricles. These Purkinje fibers are FAST conducting. This accounts for the very brief duration of the QRS complex in

1 second). normal ECG’s (<0.ii. Pathophysiology:

a) Left Bundle Branch Block (LBBB): this is an interruption/slowing of conduction through the left bundle. Hence the impulses first descend the right bundle through the RV, and then slowly propagates through the myocardial tissue to depolarize the LV. The QRS complex is therefore widened (>0.12s)- see below.

t ventricle. The QRS is widened, reflecting the slowed conduction, but in a different pattern, seen below.

iii.

b) Right Bundle Branch Block (RBBB): this is analogous to the LBBB. However, in this instance, the

impulse conducts primarily thru the left bundle and ventricle, then thru the myocardial tissue of the righ

Etiologies: Conduction system disease may be due to fibrosis, degeneration of the fibers, ischemia, infarction or

mmation. LBBB is more often reflective of significant underlying heart diseae than is RBBB.

3.

infla

CLINICAL. Many of the bradyarrhythmias and conduction disorders are asymptomatic. If symptoms are present, they most often are a feeling of fatigue and/or dyspnea on exertion. Syncope may occur with advanced block of either the SA or AV nodes. Once a clinical correlation has been made, reversible causes such as use of medications with negative chronotropy, electrolyte imbalance, or hypothyroidism, sought be sought and corrected if present. Otherwise, implantation of a pacemaker will usually stabilize the rhythm and alleviate symptoms.

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2. TACHYARRHYTHMIAS These are arrhythmias with rates exceeding 100bpm (defined strictly as having more than 3 consecutive beats). These may be present continuously (sustained) or intermittently (paroxysmal). The most important and common tachyarrhythmias will be discussed here. They may be divided into two groups - those arising from ABOVE the ventricle, called supraventricular, and those arising in the ventricle itself, called ventricular. SUPRAVENTRICULAR ARRHYTHMIAS 1. SINUS TACHYCARDIA This is the most common supraventricular tachycardia and is a normal response to physical activity and severe illness. When present with another illness, such as infection/fever, or anemia, treatment of the underlying illness will lead to resolution of the tachycardia. Rarely, patients may have an inappropriate, persistent sinus tachycardia requiring treatment, with either medication (beta blocker) or partial ablation of the sinus node. 2. ATRIAL FIBRILLATION (AF) Except for sinus tachycardia, this is the most common sustained tachyarrhythmia, and is especially prevalent in the elderly. It is frequently sustained, but may also be paroxysmal. It is characterized by chaotic/disorganized electrical (and therefore mechanical) activity in the atria, leading to an irregular ventricular rhythm. The rate of the ventricular response is variable, and may range from below 50bpm to greater than 170bpm. A rhythm strip of atrial fibrillation is shown in the chapter on ECG, page 29. It is generally caused by cardiac disorders that increase pressure within the atria, leading to enlargement of the chamber(s). Other causes include inflammation of the atrial tissue, and excessive stimulation. Some specific etiologies are listed below:

i. Etiologies: CARDIAC Hypertension Valvular Heart disease (esp MR/MS) Ischemic disease Cardiomyopathies Pericardial disease

NON-CARDIAC Toxins - alcohol Endocrine - thyrotoxicosis Pulmonary disease Neurologic disorders Idiopathic

Post Cardio-thoracic surgery Congenital heart disease

ii. Pathophysiology:

• The rate of the ventricular response to the atrial electrical activity will depend on conduction through the AV node. It is generally rapid, but may be slowed for a variety of reasons (see previous chapter), and drugs that slow AV nodal conduction are an important therapy in the treatment of AF (rate control).

• The loss of atrial function - especially atrial systole - results in stasis of blood in the LA (especially in the appendage), and this leads to an increased risk of thrombus formation and subsequent systemic embolism.

• If the AF is sustained and rapid it may lead to CHF and LV dysfunction, or may provoke ischemia in patients with existing coronary disease. How well the atrial fibrillation is tolerated depends on the status of the ventricle. The loss of atrial systole impairs cardiac function, and a fall in CO may be seen - this is especially true if there is systolic or diastolic ventricular dysfunction.

iii. Clinical Features:

Symptoms vary widely. A number of patients are asymptomatic. Minor symptoms include palpitations, fatigue, lightheadedness and shortness of breath. More severe symptoms such as angina, heart failure symptoms and hypotension may occur if the AF is poorly tolerated. Neurologic features may predominate if there has been a stroke from embolized LA thrombus. On examination the pulse is irregular - and the pulse volume varies widely due to the varyng filling periods (less filling time, smaller stroke volume/greater filling time, greater SV). Some ventricular systoles may produce a very low stroke volume - and not be palpable at the radial pulse - leading to the so-called “radial-apical pulse deficit”. Look for signs of an underlying cause of AF, eg: thyrotoxicosis, mitral stenosis, and for signs of cardiac compromise - hypotension and heart failure.


ECG: as we have seen, this reveals the absence of discrete P waves. Irregular, “fibrillatory waves” representing atrial activity may be seen, with an irregular and typically rapid ventricular response. ECHO: Transthoracic echo is helpful in determining the underlying etiology (hypertensive heart disease, mitral valve disorder, ventricular dysfunction etc). However, to make the diagnosis of an atrial thrombus (which may be important in management) a transesophageal echocardiogram (TEE) is needed.

iv. Treatment: The management of AF is complex. Decisions revolve around the acuity of the AF, the presence of

underlying cardiac disease, and how well the patient is tolerating it hemodynamically. There are two broad management strategies, rate control and rhythm control. Neither has been demonstrated to be superior for all patients. To summarize:

• rate control – use of rate slowing drugs, including B blockers, nondihydropyridine calcium channel blockers, and digoxin.

• Rhythm control – conversion to sinus rhythm may be done pharmacologically, by direct current cardioversion, or with intracardiac catheters (ablation therapy). Maintenance of sinus rhythm requires continued medication, with the exception of ablation therapy.

All patients with sustained or paroxysmal atrial fibrillation must be assessed for the risk of thromboembolic stroke. A scoring system named the CHADS-II score is used by most physicians. A point is assigned for each notable risk factor, with the exception of a previous stroke, which receives II points. The risk factors include- CHF (C), hypertension (H), age >75 (A), diabetes (D), and stroke (S). Patients with 1 point are low risk (1%/ year) and treated with aspirin, patients with 2 points are intermediate risk (2-4%/ year) and treated with either aspirin or Coumadin, and patients with >2 points are high risk (>5%/ year) and treated with Coumadin. Clinical judgement must also be used, as anticoagulation carries a risk of bleeding, and thus not all patients may benefit from anticoagulation therapy. 3. ATRIAL FLUTTER This differs from atrial fibrillation in that the rapid atrial activity is organized (flutter waves). These flutter waves result from a reentrant circuit (see below for discussion of “reentry”) in the right atrium. This leads to an atrial rate of ~300bpm. Most commonly every second atrial flutter wave is conducted to the ventricle (a 2:1 block), and the resulting ventricular response is a regular rhythm at a rate of 150bpm. The example shown has a 4:1 block, and therefore a ventricular rate of ~75. The clinical presentation is similar to that seen with AF, and the approach to treatment is also similar. A few caveats: flutter is more difficult to rate control, ablation is more successful, and flutter has the same risk of stroke as fibrillation.

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3. SUPRAVENTRICULAR TACHYCARDIA (SVT) This term is used to describe tachycardias that arise from abnormal electrical circuits that use the AV node as part or all of the circuit. These circuits most often lead to a rapid, regular and narrow QRS complex tachycardia. There are many reasons that such an electrical circuit might arise. We will discuss the underlying pathophysiology of the “re-entrant circuit” and the two most common examples of SVT.

i. Pathophysiology: the key concept here is “reentry”. Anatomically this requires that there be 2 (or more) areas of cardiac tissue that have different conduction and refractory properties, and that these 2 areas are joined in a loop. There must also be a temporary or fixed block to conduction in one direction in one of the loops. Such an anatomical arrangement may allow a premature beat (eg: an APC) to set up a continuously cycling electrical circuit. NB: This is a complex concept, and is not expected to be understood in detail at this stage. For your interest we have reproduced Figure 230-8 from Harrisons textbook, which explains reentry in a sequential fashion.

Figure 230-8: Mechanism of AV nodal reentry: The atrium, AV node (AVN), and His bundle are shown schematically. The AV node is longitudinally dissociated into two pathways, slow and fast, with different functional properties (see text). In each panel of this diagram, blue lines denote excitation in the AV node, which is manifest on the surface electrocardiogram, while black lines denote conduction, which is concealed and not apparent on the surface electrocardiogram. A. During sinus rhythm (NSR) the impulse from the atrium conducts down both pathways. However, only conduction over the fast pathway is manifest on the surface ECG, producing a normal PR interval of 0.16 s. B. An atrial premature depolarization (APD) blocks in the fast pathway. The impulse conducts over the slow pathway to the His bundle and ventricles, producing a PR interval of 0.24 s. Because the impulse is premature, conduction over the slow pathway occurs more slowly than it would during sinus rhythm. C. A more premature atrial impulse blocks in the fast pathway, conducting with increased delay in the slow pathway, producing a PR interval of 0.28 s. The impulse conducts retrogradely up the fast pathway producing a single atrial echo. Sustained reentry is prevented by subsequent block in the slow pathway. D. A still more premature atrial impulse blocks initially in the fast pathway, conducting over the slow pathway with increasing delay producing a PR interval of 0.36 s. Retrograde conduction occurs over the fast pathway and reentry occurs, producing a sustained tachycardia (SVT).

ii. AVNRT (AV nodal reentrant tachycardia). The AV node contains both pathways for conduction. The reentrant circuit is entirely within the AV node. This is the prototype for reentry - and the one illustrated in the diagram above.

iii. AVRT (AV reentrant tachycardia).

In this case the second limb of the circuit is an abnormal band of conduction tissue between the atria and the ventricles - called an “accessory pathway”.

iv. Clinical. Both of the above SVT’s produce the typical ECG of SVT - a rapid regular rhythm with a narrow QRS complex. No P waves can be seen preceding the QRS complex. This is shown on the ECG on the following page. Clinically, SVT causes paroxysmal palpitations - and may be associated with presyncope or even syncope. Neck pounding is also common - especially in AVNRT. Episodes may be precipitated by emotional stress, caffeine and alcohol. The diagnosis is initially made with a 12 lead ECG taken during the arrythmia. Once again an “event monitor” may be very helpful to capture clinical events occurring only every few days or weeks. An EP study will confirm the electrical abnormalities.

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ECG example of an SVT

v. Treatment:

• Acute episodes: maneuvers that increase vagal tone (such as the valsalva and carotid massage) will slow AV conduction and may “break” the SVT. Alternatively ,drugs such as adenosine will accomplish the same thing.

• Chronic: Frequent, symptomatic SVT is now primarily treated with catheter ablation techniques, although drugs may also be used.

vi. Special note: The delta wave. Some patients with accessory pathways

have an abnormal ECG at baseline, due to the presence of “preexcitation”. This abnormality is shown here, and is termed a “delta wave”. It occurs because there is slightly early depolarization of the ventricle by an atrial impulse conducting down a relatively fast accessory pathway (faster than the AV node). Note that this means the PR interval is short. This is often referred to as WPW syndrome, after Drs. Wolff

- Parkinson-White, who first described it.

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VENTRICULAR ARRHYTHMIAS 1. VENTRICULAR TACHYCARDIA This is a rapid regular rhythm originating in the ventricle and therefore almost always a wide QRS complex is present. Along with ventricular fibrillation (VF), it is a major cause of cardiac death. Most ventricular tachycardia (VT) arises from the formation of reentrant circuits in myocardium which has been scarred - as in ischemic cardiomyopathy for example. An LV aneurysm is an especially important focus for the generation of VT.

i. Etiologies: Coronary disease (very common), dilated cardiomyopathy, HCM, arrhythmogenic RV dysplasia (rare), inherited “long QT” syndromes, inherited Brugada syndrome, and drugs which lengthen the QT interval.

ii. Clinical: The presentation will depend on the hemodynamic consequences of the rhythm. This in turn depends on

the rate of the VT, and the degree of underlying ventricular dysfunction. Symptoms may therefore vary from sudden cardiac death, to syncope, cardiogenic shock, shortness of breath or chest pain.

The ECG shows a rapid rate with a regular rhythm and a wide, bizarre QRS complex - see below.

Management:

a. Acute: As most patients are severely compromised, this is a medical emergency, and part of the life support

protocol. Immediate electrical cardioversion is the treatment of choice, supplemented by drugs such as amiodarone and procainamide to prevent recurrence.

b. Chronic: Patients who have symptomatic VT (syncope or sudden death), are treated with a defibrillator, which

monitors their heart rhythm, and delivers an internal shock to convert them to sinus rhythm, should VT recur. This is the only therapy proven to improve the mortality of such patients. Patients who have not suffered VT, but who are at high risk to do so (severe LV dysfunction, EF<30%), are treated with defibrillators for primary prevention of sudden death.

2. VENTRICULAR FIBRILLATION. This is a pre-terminal rhythm that may result from degeneration of untreated VT, or arise de novo. The underlying causes and treatment are therefore very similar to VT. There is no cardiac output, and the occurrence of this rhythm constitutes a cardiac arrest. Immediate electrical shock is the only therapy, and needs to occur as soon as possible (<5 mins) to have any substantial chance of restoring a normal rhythm, and surviving with preserved brain function.

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SECTION E

HYPERTENSION

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1. HYPERTENSION Hypertension is the most common cardiovascular disorder. Although its prevalence varies according to age, ethnic background and other factors, between 25 and 50% of people in developed countries have hypertension, when defined as a blood pressure > 140/90 mmHg. To properly measure blood pressure, a patient should be seated, and the arm resting at the level of the heart. The cuff bladder should encircle at least 80% of the circumference of the arm. The average of at least three measurements, taken no more frequently than weekly, should be used as the defining blood pressure. The most recently released report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC-VII) has classified blood pressure according to degrees of both normality and abnormality, as listed below:

Classification of Blood Pressure for Adults 18 and Older (JNC VII) Category Systolic, mmHg Diastolic, mmHg Optimal < 120 and < 80 Prehypertensive 120-139 or 80-89 Hypertension Stage I 140-159 or 90-99 Stage II >160 or ≥100 With age, blood pressure increases, especially the systolic pressure. After the age of 65, approximately 2/3 of hypertensive patients will have isolated systolic hypertension, related to the loss of compliance of the major arteries. Hypertension is divided into TWO categories, primary, also called essential or idiopathic, and secondary. Primary hypertension comprises more than 95% of all hypertensive patients. A. PRIMARY HYPERTENSION 1. Pathophysiology

Primary hypertension is hereditary, and usually occurs between the ages of 25 and 55. No single genetic abnormality has been discovered, but several abnormalities of the renin-angiotensin system have been linked to hypertension.Several environmental contributors have been found as well, including obesity, increased salt and alcohol intake, and certain high stress occupations. Hypertension, especially when combined with other risk factors of atherosclerosis, leads to damage of several end organs. These organs and their clinical findings include:

Heart • left ventricular hypertrophy • congestive heart failure • ischemic heart disease

Aorta • aneurysm • dissection

Peripheral arteries • obstructive atherosclerosis

Brain • stroke

Kidneys • nephropathy

Eyes • retinopathy

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Most patients, especially with stage I hypertension, are entirely asymptomatic. However, headache is the most frequent symptom in uncomplicated hypertension, while accelerated stage II hypertension may cause central neurologic symptoms including blurred vision, confusion/somnolence, and nausea/vomiting.

3. Evaluation

The physical examination focuses on detectable end organ damage, including: • fundoscopy to detect retinopathy • cardiac exam to detect ventricular enlargement, atrial gallop (S4) • vascular exam to detect atherosclerosis, ie bruits & pulse deficits, and the

pulse lag of coarctation Laboratory studies routinely include only:

• serum electrolytes • serum creatinine

Electrocardiogram, looking for left ventricular hypertrophy Additional studies are done only for specific indications arising from the initial evaluation.

4. Management

JNC-VII has developed a scheme of treatment which incorporates global risk, based on findings of target-organ damage (TOD) and the presence/absence of diabetes mellitus (DM), clinical cardiovascular disease (CCD) and/or risk factors of atherosclerosis (RFs). The council emphasizes lifestyle modification for all stages.

There are many medication options available. Those most frequently used include thiazide diuretics, ACE inhibitors, ARBs (angiotensin ll receptor blockers), beta blockers and calcium channel blockers (CCB). Many factors may go into the selection of a specific medication(s), including associated disorders, age, ethnic background, cost, and side effects. A detailed discussion is beyond the scope of this syllabus.

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B. SECONDARY HYPERTENSION If hypertension develops outside the parameters outlined for primary hypertension, or findings during the initial evaluation specific for an alternate etiology are present, then secondary hypertension should be suspected. Secondary hypertension is present in only 5% of patients with HTN, and many of the underlying endocrinopathies and other disorders are very rare. The most common forms are listed below, roughly in descending order of frequency. As the diagnosis of secondary HTN requires a high clinical suspicion, the features that suggest a secondary etiology are also listed below:

1. Renovascular age > 60, widespread atherosclerosis, rapid worsening of existing primary HTN at an older age, poor response to Rx (multiple drugs needed). age > 30 (esp. women, non-African American) non-atherosclerotic renal artery disease - fibromuscular dysplasia - should be suspected.

2. Renal parenchymal abnormalities in screening lab 3. Oral contraceptive induced history 4. Primary aldosteronism low potassium on screening labs 5. Cushing’s syndrome Typical physical findings - central obesity, “moon facies” striae etc. 6. Pheochromocytoma Paroxysmal episodic hypertension, tachycardia, associated orthostasis 7. Coarctation young age, radio-femoral delay, BP difference between arm and thigh.

The complete evaluation of each of these disorders is beyond the scope of this syllabus.

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SECTION F

PROBLEM SETS

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SET I Case 1.

A 55 y/o man presents to the emergency room with a complaint of chest pain. Two hours prior to arrival at the ER he had an episode of pain that began while he was doing moderate yard work. He describes it as a squeezing pain in the lower central and left chest that worsened over several minutes, spreading to both shoulders. It was relieved in about 10 minutes by sitting down. He was very breathless during the episode, and feels that the pain may have been worse on deep breathing.

He has a past medical history of hypertension, controlled on hydrochlorthiazide 25mg daily, and of a “high” cholesterol which has not been treated. His father died suddenly of a possible heart attack at age 45. The patient smoked 2 packs per day for 35 years, stopping 2 years ago, and returned from a business trip to Buenos Aries two days ago.

On the initial physical examination his vital signs are HR = 85, BP = 160/95mmHg. His pulse is regular, and he has normal first and second heart sounds. His lungs are clear with normal breath sounds. His abdominal examination is unremarkable.

1. Features of this patient’s chest pain that might be typical for cardiac ischemia include all of the following except:

a. squeezing pain b. radiation to the shoulders c. association with breathlessness d. exacerbation by deep inspiration e. relief with rest

2. You decide to perform a more complete physical examination. Physical signs that might (if present) suggest an ischemic

etiology for this pain include: a. presence of a pericardial friction rub b. localized tenderness of the chest wall c. presence of abdominal and left carotid bruits d. a swollen and tender left lower extremity

3. There were no further findings on physical examination. What are the next most appropriate test(s) to obtain urgently:

a. PA/Lat chest X-ray b. ECG and cardiac biomarkers c. CBC d. serum amylase, electrolytes and creatinine e. hepatic enzymes

4. His CXR was unremarkable, and his CBC, electrolytes, creatinine and hepatic enzymes were normal. His initial troponin was <0.1, and his ECG is shown. See ECG 1. :

What is the most likely etiology for this patient’s episode of chest pain?

a. cardiac ischemia b. pulmonary embolism c. pericarditis d. musculoskeletal pain e. gallstone pancreatitis

5. After a stay of 6 hours in the ER he is re-evaluated. No further abnormal results were obtained during that time, and he remains pain free. The next most appropriate test in determining the etiology of this patients chest pain would be:

a. Pulmonary V/Q scanning b. echocardiography to rule out a pericardial effusion c. cardiac stress testing d. abdominal ultrasound e. cardiac catheterization - coronary angiography

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Case 2.

A 65 y/o man is brought to the emergency room by ambulance after an episode of sudden loss of consciousness. The patient remembers little of the event, but says that he feels quite well now, and would prefer to “just go home”.

He has prior history of an anterior myocardial infarction 4 years previously, and a cardiac echo 3 years ago demonstrated an ejection fraction of 30% with an antero-apical aneurysm. Shortly after his MI he suffered a left cerebrovascular accident with mild right hemiparesis, but he has made a full recovery from this. He has had diabetes for the past 15 years, and is now using subcutaneous insulin twice daily. His other medications include aspirin 325mg daily, lisinopril 10mg daily and simvastatin 40mg daily. He continues to use alcohol excessively, with 6-8 beers per day.

On physical examination he is alert and orientated. His pulse is regular and 80bpm and his blood pressure 140/90mmHg. There are no abnormalities on head and neck examination, and no carotid bruits are heard. His cardiac apex is laterally displaced and diffuse. He has normal first and second heart sounds, and a soft (grade 2/6) holosystolic murmur heard best at the apex and radiating to the axilla. His lungs are clear on auscultation. A full neurological exam reveals no focal findings.

1. The patient’s wife arrives in the emergency room. She witnessed his collapse. The description of the episode she gives

suggests a cardiac cause for the episode. Features of her report might have included all of the following except: a. abrupt loss of consciousness with no apparent warning b. rapid recovery to normal after the event c. incontinence of urine or feces d. complaints of chest pain or palpitations just prior to the event

2. Information regarding past history may be very important in determining the likely reason for a syncopal event. The most

important feature of this patient’s history is: a. His prior CVA and right hemiparesis b. His diabetes and insulin use c. His prior echocardiographic findings d. his alcohol use

3. What is the next most appropriate test(s) to obtain urgently.

a. EEG b. CT Head c. ECG d. Serum glucose and electrolytes

4. The patient’s head CT demonstrated an old left middle cerebral artery CVA, and his blood chemistries were normal. His

ECG (See ECG 2) reveals an anteroseptal myocardial infarction and ST changes suggesting either recent injury or the presence of a ventricular aneurysm. The most likely cause for the episode of loss of consciousness is:

a. seizure related to his prior CVA b. paroxysmal ventricular tachycardia related to prior MI/LV aneurysm c. hypoglycemia secondary to excessive insulin use d. paroxysmal atrial fibrillation related to prior MI e. valvular heart disease

5. What is the most appropriate management plan for this patient:

a. discharge to home with a 24 hour heart monitor and follow-up by cardiology in 2 weeks b. admission with telemetry (heart rhythm) monitoring and cardiology consultation c. discharge with a beta-blocker and cardiology follow-up in 3 days d. admission to the neurology service for EEG monitoring

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SET II Case 3

A 60 y/o woman is referred to your office for evaluation of chest pain. She first noted the symptoms 6 or 7 weeks ago. They are described as a burning and heaviness in the lower chest or epigastrium, and seem to occur with activities such as tennis, climbing the two flights of stairs at work, or doing heavy housework such as vacuuming carpets. Sometimes there is an associated feeling of shortness of breath, but no other symptoms are noted. The symptoms have never lasted more than 5 or 10 minutes. In the past week, she has noted sharp, shooting pains under her left breast, prompting her to seek medical evaluation. Otherwise, her symptoms have been unchanged. She has a past medical history of a hiatal hernia, which was treated with ranitidine, which she stopped taking a month ago. She is postmenopausal, and is not taking hormone replacement therapy. On physical examination, she is apprehensive. Her vital signs include a pulse rate of 80 bpm, blood pressure of 145/85mmHg, and respiratory rate of 20 breaths per min. The exam is otherwise unremarkable. 1. All of the following features are typical of angina except:

a. burning chest discomfort b. exertional dyspnea c. sharp precordial pains d. symptoms associated with activity e. radiation of discomfort to the jaw or upper extremities

2. Based on the information available thus far:

a. she should resume medication for her hiatal hernia b. she has unstable angina and should be hospitalized for evaluation/treatment c. she has musculoskeletal pain and should take it easy for a few days d. she has New York Heart Association class II angina and may be

evaluated/treated as an outpatient 3. She undergoes an exercise stress test. At the beginning of the fourth stage of the Bruce protocol, she develops her

typical symptoms at a heart rate of 145 bpm and blood pressure of 190/75 mmHg. There is 1.5 mm of horizontal ST segment depression in the inferior leads, which resolves in less than 3 minutes. Nuclear imaging reveals a small, inferior wall, reversible defect and normal left ventricular function (as measured by ejection fraction).

All of the following additional information is necessary to guide treatment of this patient except::

a. a fasting lipid panel b. smoking history c. Coronary angiography d. a fasting blood sugar e. calculation of her body mass index (BMI)

4. The lipid panel reveals the following: total cholesterol 260, LDL cholesterol 150,

HDL cholesterol 38, triglycerides 145. Using the American Heart Association guidelines, which of the following would be the primary/principle treatment goal(s) for this patient?

a. lower the LDL cholesterol to < 100 (optional <70) b. lower triglycerides to < 100 c. lower the LDL to < 50, and raise the HDL to > 50 d. lower the total cholesterol to < 200

5. Symptoms and objective findings of myocardial ischemia may be predictably provoked by exercise because:

a. exercise typically provokes coronary artery spasm, resulting in myocardial ischemia b. there is a reduction in coronary flow reserve in the presence of a mild (25%-50%) coronary stenosis c. there is a reduction in coronary flow reserve in the presence of a moderate or severe (>75%) coronary stenosis d. exercise frequently results in rupture of atherosclerotic plaque in the coronary arteries, producing ischemia

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Case 4

A 55 y/o man comes to the emergency room complaining of intense epigastric/chest pain which has been present for approximately 1 hour. He vomited earlier and continues to be nauseated. There is radiation of pain to the back and he feels short of breath. His past medical history is remarkable only for cigarette smoking (30 pack years). On physical examination, he is obviously uncomfortable and diaphoretic. His blood pressure is 100/60 mmHg, pulse rate 120 and respiratory rate of 25. His JVP is normal, but a few crackles are present at the lung bases. Cardiac auscultation reveals an S4 gallop, and no murmurs or rubs. The abdomen is soft and non-tender. Pulses are full and equal, but his peripheries are cool and clammy. There is no peripheral edema. An electrocardiogram was obtained - see ECG 3 1. The diagnosis is:

a. unstable angina b. pulmonary embolus c. NSTEMI d. An inferior STEMI e. An anterior STEMI

2. The most likely underlying etiology is:

a. acute coronary arterial spasm b. aortic dissection c. plaque rupture and coronary artery thrombus d. spontaneous coronary artery dissection e. coronary artery embolus

3. Which of the following immediate therapies has been proven to reduce his mortality from this event?

a. intravenous nitroglycerin b. aspirin c. morphine sulfate d. oxygen e. dopamine

4. Reperfusion therapy is considered for this patient. Which of the following statements regarding this strategy is true?

a. Reperfusion therapy is unlikely to benefit him at this time, due to his delay in seeking medical attention b. Thrombolytic therapy is contraindicated, due to his hypotension c. Primary angioplasty is not indicated due to the clinical diagnosis of cardiogenic shock. d. Thrombolytic therapy will result in a risk of intracranial hemorrhage of approximately 0.5-1%

The patient is taken emergently to the cardiac catheterization laboratory, where he is treated. Among the findings, his ejection fraction is found to be 35%. 4. Based on the findings, all of the following medications are indicated, except:

a. An ACE inhibitor b. A Calcium channel blocker c. A Beta blocker d. An HMG CoA reductase inhibitor e. Aspirin

5. Despite his emergent treatment he remains at risk for all of the following complications except:

a. Congestive heart failure b. Ventricular tachycardia c. Severe aortic regurgitation d. Acute ventricular septal defect/rupture

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Case 5 A 40 y/o truck driver is brought to the emergency room. He experienced the sudden onset of severe, tearing, substernal chest pain while driving and pulled his truck to the side of the road. The pain continued and spread into the midscapular region of his back. His past medical history is remarkable for a long history of hypertension. It was previously treated with a diuretic and ACE inhibitor, but he stopped taking his medications some time ago.

On physical examination, he remains uncomfortable. His blood pressure is 180/110 mmHg in the right arm, the pulse is 120 bpm, respirations are 20 breaths/min. Fundoscopy reveals severe arteriolar narrowing and moderate AV nicking. The carotid upstrokes are normal and there are no carotid bruits. The lungs are clear. Cardiac auscultation reveals only an S4. The abdominal exam is normal. The femoral pulses are normal and free of bruits. There is no clubbing, cyanosis, or edema. 1. The most important additional aspect of the physical examination to perform would include:

a. palpation of the back for muscle spasm or point tenderness b. measurement of the blood pressure in both arms c. examination of the JVP for Kussmaul’s sign d. examination for radio-femoral delay

2. An electrocardiogram was taken: see ECG 4

It reveals: a. P pulmonale b. Acute ST elevation consistent with myocardial infarction c. Left ventricular hypertrophy d. Right ventricular hypertrophy

3. Given his clinical presentation the chest radiograph may show all of the following except:

a. A small left pleural effusion b. A widened mediastinum c. Cardiomegaly d. A calcified pericardium

4. A transesophageal echocardiogram is ordered and demonstrates a dissection flap in the ascending aorta. The most appropriate management for this patient is:

a. medical therapy with B blockers b. Emergent surgery c. Immediate IV B Blockers and emergent surgery d. Emergent cardiac catheterization

The patient suddenly deteriorates, with reduced mentation and worsened dyspnea. Reexamination reveals the blood pressure to be 80/40 mmHg, with an inspiratory drop to 55 mmHg. The radial pulse is weak and disappears during inspiration. The extremities are cool and clammy. The heart sounds are nearly inaudible. 5. The most likely complication is:

a. ruptured abdominal aortic aneurysm b. papillary muscle rupture c. massive pulmonary embolus (“saddle embolus”) d. cardiac tamponade e. left ventricular rupture

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Case 6

A 65 y/o man returns for routine follow up of coronary artery disease. He had a myocardial infarction 5 years ago and reports that he currently has no symptoms of angina. He has however reduced his walking and other activities due to pain which develops in his legs. It involves the buttocks and legs, and is bilateral. It usually occurs after walking two or three blocks, and is relieved with sitting or resting. If he slows his pace, he can either avoid the pain, or “walk through it”.

He has additional history of an old back injury, hypertension, poorly controlled diabetes, and hyperlipidemia. Additionally, he reports an episode of transient loss of vision in his left eye two weeks ago. He is taking aspirin and a beta blocker. Since his infarct, he has reduced his smoking habit to less than 1 PPD.

On examination, his blood pressure is 130/75 mmHg, pulse is 70 and regular. His lungs are clear, and his JVP is normal. Bruits are present in both carotids. A grade II/VI systolic ejection murmur is heard along the left sternal border, and does not radiate. A bruit is present over the abdomen and the aorta palpates to less than 4.0 cm. There is no peripheral edema.

1. All of the following are typical of both “neurogenic” and “vascular” claudication, except:

a. precipitated with walking b. bilateral involvement c. buttock and leg involvement d. relief with slowing of the walking pace

2. Which of the following findings on physical examination would suggest a vascular etiology for this pain?

a. A “straight leg raise” produces shooting pains and tingling in his right foot b. His distal pulses are estimated at 2+ bilaterally c. The skin of the lower part of both legs is cool and hairless d. He has numbness and reduced sensation in the lateral border of the foot.

3. Which further study would be the most helpful at this time?

a. fasting lipid panel b. MRI of the lumbar spine c. measurement of the ankle/brachial index d. abdominal ultrasound

4. The most appropriate management at this time would include all of the following except:

a. addition of a calcium channel blocker to his regimen b. smoking cessation c. daily walking d. commencement of simvastatin, 40mg daily e. advice about appropriate footwear

5. Although the physical examination revealed findings of diffuse atherosclerosis, his clinical history suggests that further

evaluation of which vascular bed should be undertaken promptly?

a. renal arteries b. abdominal aorta c. carotid arteries d. coronary arteries

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SET III Case 7

A 72 y/o man presents to the emergency room with shortness of breath, cough and breathlessness when lying down. These symptoms began a week ago and have rapidly worsened. He has been able to sleep only when sitting in a chair, and is breathless even at rest. He does not report palpitations or other cardiac symptoms.

He has a past history of a “heart attack” 4 years ago, and an echocardiogram 2 years ago is reported to show poor LV function. He has not seen a physician for the past 12 months, and is taking furosemide 20mg and aspirin 325mg daily. He has been largely sedentary over the past few months.

On examination he has a rapid irregular pulse, rate ~140bpm, BP = 110/70 mmHg, and the respiratory rate is 30. His JVP is elevated at +18cm above the RA, and has a monophasic waveform. His first heart sound is variable in intensity,and an S3 is audible. Fine inspiratory crackles are heard in the lower half of both lung fields, associated with pronounced expiratory wheezing. His abdominal examination is unremarkable, and he has trace edema in the lower extremities. His ECG is shown - See ECG 5: 1. The most likely etiology for his shortness of breath is:

a. acute myocardial infarction b. pulmonary embolism c. asthma d. congestive heart failure e. bacterial pneumonia

2. The ECG demonstrates which of the following rhythm disturbances:

a. ventricular tachycardia. b. atrial fibrillation c. atrial flutter d. a reentrant supraventricular tachycardia

3. The most likely reason for this patient’s rapid deterioration is: a. excessive salt intake b. medication non-compliance c. new-onset tachyarrhythmia d. worsening myocardial ischemia e. occult thyrotoxicosis 4. A CXR performed shows cardiomegaly, increased pulmonary vascularity, small pleural effusions and Kerley B lines.

Initial acute management in the emergency room might include all of the following except:

a. Diuresis with furosemide 40mg IV b. Emergent DC cardioversion c. Anticoagulation with heparin IV d. Commencement of digoxin IV e. Oxygen

5. Which of the following statements about this patient’s current hemodynamic status is true:

a. His stroke volume (SV) is increased b. His preload is reduced c. His pulmonary capillary wedge pressure is increased d. His right atrial pressure is normal

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6. The patient was admitted, stabilized and eventually discharged after considerable improvement. He now sees you in the

outpatient clinic for follow-up. He has minimal breathlessness on exertion only, and is in normal sinus rhythm on ECG. Ongoing therapy proven to improve his long term mortality would include all of the following except:

a. ACE inhibitor b. B Blocker c. Anticoagulation with coumadin (goal INR 2-3) d. Rate lowering calcium channel blocker

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Case 8

A 75 y/o woman is referred to your office for evaluation of shortness of breath. She had been in excellent health until several months ago, at which time she noted the progressive onset of

dyspnea on exertion. Currently, she is limited to less than 1 block and is unable to climb 1 flight of stairs before she must stop to catch her breath. There is a substernal chest tightness associated with the shortness of breath. She denies orthopnea and paroxysmal nocturnal dyspnea.

The past medical history is remarkable for hypertension, hyperlipidemia and a light smoking habit (20 pack years). On physical examination, the blood pressure is 105/65, pulse 70 and regular, respirations 15. The JVP is of normal

height and contour, and the lungs are clear. The carotid upstroke is slow, with a pronounced anachrotic notch. There is a palpable atrial gallop and the apex is sustained. Auscultation reveals an S4, and normal S1, while A2 is diminished. A grade III/VI systolic ejection murmur is heard, and is loudest along the left sternal border. It peaks in late systole. An abdominal bruit is heard. Peripheral pulses are intact, and there is no edema. An electrocardiogram was obtained - see ECG 6: 1. The most likely diagnosis is:

a. Mitral regurgitation b. Aortic regurgitation c. Aortic stenosis d. Mitral stenosis

2. All of the following physical findings suggest that the lesion is severe, except:

a. reduced A2 (second sound) b. S4, atrial gallop c. sustained apical impulse, or heave d. late peaking murmur e. slow carotid upstroke

3. An echocardiogram confirms your clinical suspicion that this patient has a signifcant valvular lesion. Which of the following sets of hemodyamics would most likely be found in this patient? LV AORTA PCWP RV RA

a. 170/10 170/100 12 30/5 4 b. 160/10 105/80 12 30/5 4 c. 105/5 105/65 27 60/25 15 d. 105/25 105/65 26 60/25 15

4. Which of the following would be the best form of management?

a. exercise program - at a cardiac rehab. center b. valve surgery following a cardiac catheterization c. digoxin d. diuretics

5. The underlying pathologic cause for this valvular lesion is most likely to be:

a. perforation of a valve leaftlet b. chronic inflammatory valvulitis c. An underlying congenital valve abnormality d. Calcified degenerative changes of the valve leaflets

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Case 9

A 44y/o man visits your office for the first time complaining of shortness of breath, fatigue, ankle swelling and increasing abdominal girth. He says that these symptoms have been gradually progressive for several years now, but he has not sought medical advice before now.

On examination he is tachycardic at 110bpm, with a regular rhythm, BP 96/70 mmHg, and his JVP is elevated at +18cm above the RA. The venous waveform appears to have a prominent Y descent. He has normal S1 and S2, with a loud early diastolic sound heard best at the apex with the diaphragm. There is dullness to percussion with absent breath sounds at both lung bases, and abdominal swelling with a positive fluid wave. His liver is palpable and 15cm by percussion. Pitting edema (3+) is present in both ankles.

1. The most likely diagnosis for this patient’s presenting illness is:

a. Mitral stenosis b. Pericardial constriction c. Cirrhosis d. Atrial septal defect e. COPD with right heart failure

2. Further close examination of this patient’s jugular venous pulse should also reveal:

a. “Cannon” a waves b. Elevation of the JVP with inspiration c. Prominent V waves d. an absent a wave

2. All of the following findings on past medical history would be consistent with this presentation except:

a. “mantle” radiation for Hodgkins lymphoma at age 22. b. tuberculosis at age 16 c. rheumatic fever at age 7 d. viral pericarditis at age 38

4. The best non-invasive test to confirm this diagnosis would be:

a. Plain PA/lat chest X ray b. Transthoracic echocardiography c. Spiral CT of the chest d. Cardiac MRI

5. The most appropriate initial therapy for this patient would be:

a. an ACE inhibitor b. a loop diuretic c. a beta blocker d. surgical intervention

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Case 10

A 22 y/o UVa student visits your office for a new patient visit. She was referred by the athletic department after failing a screening medical examination for the women’s basketball team.

She reports mild exertional shortness of breath, and a gradual reduction in exercise tolerance over the past 5 years. She has no significant past medical history, and her only medication is an oral contraceptive pill.

On physical examination her pulse is regular, rate = 75bpm, BP = 110/70 mmHg. Her JVP is slightly elevated at 12 cm above the RA. Cardiac exam reveals a normal first heart sound, and a widely split second heart sound that does not vary with respiration. Her lungs are clear, her abdominal examination is normal and she has no peripheral edema. An ECG is performed and is shown - see ECG 7: 1. The ECG demonstrates:

a. Normal variant in a young patient b. ST segment changes consistent with ischemia in V1-V3 c. Sinus tachycardia, with right ventricular hypertrophy and biatrial enlargement d. Long QT interval

2. The underlying pathologic cause for this cardiac abnormality is:

a. Incomplete growth of the secundum septum b. Persistence of the ductus arteriosis c. Excessive growth of the primum septum d. A defect in the membranous interventricular septum

3. Further careful physical examination might reveal all of the following except:

a. an RV “lift” at the R sternal border b. a soft (2/6) systolic ejection murmur at the upper L sternal border c. a low pitched diastolic murmur at the lower L and/or R sternal border d. central cyanosis

4. Your clinical suspicion is confirmed by Echocardiography.

Which of the following statements regarding this condition is true: a. There will be a reduction in right ventricular volume b. The oxygen saturation in the right atrium will be elevated c. There will be early closure of the pulmonic valve d. There is a lesser volume of blood in the pulmonic circuit compared with the systemic circuit.

5. The potential consequences of leaving this abnormality untreated include all of the following except:

a. Right ventricular failure b. Atrial fibrillation c. Pulmonary hypertension d. Left ventricular failure

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SET 1. Question 1. ECG 1

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SET 1. Question 2. ECG 2.

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SET II Question 2 ECG 3.

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SET II Question 3 ECG 4.

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SET III Question 1 ECG 5.

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REFERENCE LIST The following textbooks and sources were used in creating this syllabus. All contain helpful information, and you are encouraged to further your reading by referring to these books.

1. Braunwald E. et al. Harrisons Principles of Internal Medicine. McGraw Hill. 15th ed. 2001.

2. Braunwald E. et al. Heart Disease: A Textbook of Cardiovascular Medicine. 6th ed. 2001

3. Crawford M, Di Marco, J. Cardiology. Mosby. 2001

4. Talley N, O’Connor S. Clinical Examination. MacLennan & Petty Publishers. 2nd ed. 1992

5. Murphy J. Mayo Clinic Cardiology Review. Lippincott Williams and Wilkins. 2nd ed. 2000

6. Topol E. Comprehensive Cardiovascular Medicine. Lippincott-Raven. 1998

7. Tierney L. et al. Current Medical Diagnosis and Treatment. Mc Graw Hill. 40th ed. 2001

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APPENDIX I - Glossary of Cardiology Terms

AAA (triple A): abdominal aortic aneurysm

A-aDO2: alveolar-arterial oxygen gradient

ABG: arterial blood gas, a collection of pO2, pCO2, pH, BE and HbSaO2 measurements from an arterial blood sample

ACE: angiotensin-converting enzyme

Acute arterial occlusion: Acute occlusion of an artery commonly by embolism, but also by thrombosis of an atheromatous lesion or vascular trauma

ABI: ankle to brachial index measuring ratio of ankle systolic blood pressure to brachial artery systolic pressure

ACTH: adrenocorticotropic hormone

MI: (acute myocardial infarction) an acute process of myocardial ischemia of sufficient severity and duration to result in permanent myocardial damage

AF/A Fib: atrial fibrillation

A Flt: atrial flutter

AI: aortic insufficiency: aortic valvular incompetence: failure of the aortic valve to close during diastole causing back flow into the left ventricle

AICD: automatic internal cardioverter/defibrillator

AIVR: accelerated idioventricular rhythm

aneurysm: the abnormal dilation or out-pouching of a blood vessel or ventricle

angina: a clinical syndrome typically characterized by a deep, poorly localized chest or arm discomfort that is reproducibly associated with physical exertion or emotional stress and relieved promptly by rest or sublingual NTG.

angiographically significant CAD: CAD is typically judged "significant" at coronary angiography if there is at least a 70 percent diameter stenosis of one or more major epicardial coronary segments or at least a 50 percent diameter stenosis of the left main coronary artery

anticoagulant: any agent that inhibits coagulation

anxiolytic therapy: treatment to counteract or diminish anxiety

aPPT: activated partial thromboplastin time

AR: aortic regurgitation, aortic insufficiency (AI)

ARDS: adult respiratory distress syndrome; a disease process where the patient's lungs fail to remove sufficient carbon dioxide and provide sufficient oxygen during ventilation

ARF: acute renal failure

arrhythmia/dysrhythmia: irregularity of the heart rhythm

arteriosclerosis/atherosclerosis/ASCVD: intimal hyperplasia of the arterial wall, leading to narrowing of the lumen and eventually to inadequate blood flow

AS: aortic valvular stenosis: narrowing of the normal aortic valve area causing a pressure drop across the aortic valve during ventricular systole

ASA: aspirin

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ASD: atrial septal defect,

ATIII: antithrombin III, an albumin cofactor that normally binds free thrombin in the blood, heparin catalyzes the anti-thrombin action of ATIII 1000 times normal

AV: 1. atrioventricular 2. aortic valve; 3. arterio venous

AVB: atrioventricular block

AV canal: atrioventricular canal

AV node: atrioventricular node

AVR: aortic valve replacement; open heart surgery to replace a diseased aortic valve with a prosthetic, artificial valve

B

BBB: bundle branch block

beta blocker (beta-adrenergic blocking agent): a drug that blocks the effect of catecholamines, producing a decrease in heart rate and oxygen demand in the myocardium

BiVAD: bi-ventricular assist device; the use of two blood propulsion devices to assist the failing right and left ventricles

Bradycardia: slow heart rate, below 60 beats per minute (BPM) BSA:

body surface area (usually in square meters) BTBV:

beat to beat variability BT Shunt :

Blalock-Taussig Shunt. BVH:

biventricular hypertrophy

C

CABG: coronary artery bypass graft

CAD: coronary artery disease

calcium channel blocker: drug that blocks entry of calcium into cells and inhibits the contractility of smooth muscle, resulting in dilation of blood vessels and reduction in blood pressure

cardiac catheterization: passage of a catheter into the heart through a blood vessel leading to the heart for the purpose of measuring intracardiac pressure abnormalities, obtaining cardiac blood samples, and/or imaging cardiac structures by injection of radio-opaque dye

cardiac output: the volume of blood displaced by the left ventricle over one minute measured as heart rate x stroke volume (HR x SV)

cardiac index:

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cardiac output normalized to body surface area cardiogenic shock:

failure to maintain adequate blood supply to the tissues because of inadequate cardiac output, such as may be caused by myocardial infarction

cardiomegaly: enlargement of the heart (a radiographic term)

cardiomyopathy: a general diagnostic term designating primary myocardial disease; the most common of these diseases is dilated cardiomyopathy in which the disease weakens the heart muscle and causes left ventricular dilation leading to increased diastolic pressure and volume.

cardiopulmonary bypass : an extracorporeal pump/oxygenator to circulate blood around the heart and lungs; used during cardiac surgery cardiopulmonary resuscitation:

an emergency measure to maintain a person's breathing and heartbeat when they have stopped as a result of myocardial infarction, trauma, or other disorder.

cardiotomy: surgical opening in the heart

catecholamine : any of a group of sympathomimetic amines (including dopamine, epinephrine, and norepinephrine)

cath: catheterization

CCSC: Canadian Cardiovascular Society Classification of angina (rarely used in USA)

CCU: coronary care unit

CHD: congenital heart disease

CHF: congestive heart failure

circ art/Cx artery: circumflex artery

CK: creatinine kinase

Compartment syndrome: increased intracompartmental pressure in the calf due to swelling or bleeding, resulting in ischemia and necrosis if not treated emergently

congestive heart failure : failure of the heart to maintain adequate circulation of blood.

coronary artery bypass graft : vein or artery grafted surgically to permit blood to travel from the aorta to a branch of the coronary artery at a point past an obstruction.

coronary artery disease (CAD): Atherosclerotic narrowing of the major epicardial coronary arteries.

coronary thrombus: blood clot that obstructs a blood vessel of the heart

coronary stenosis: narrowing or constriction of a coronary artery

CVP: central venous pressure

D Diastole: the period of time during relaxation and filling of the ventricle(s)

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DIC: disseminated intravascular coagulapathy; an abnormal process that occurs when clot formation and clot lysis occurs simultaneously in the microcirculation

DOE: dyspnea on exertion DVT:

deep venous thrombosis dyspnea :

shortness of breath, difficulty breathing

E ECA: external carotid artery ECD:

endocardial cushion defect ECG :

electrocardiogram ECHO:

echocardiogram echocardiography:

the process of reflecting ultrasound and doppler signals off the heart and surrounding structures to visualize cardiac anatomy and function, and to assess valvular, myocardial and pericardial physiology

EF/ejection fraction: ejection fraction; the percent of the left ventricular volume that is ejected in one cardiac contraction

EKG: electrocardiogram

embolus: a small solid particle or gas bubble that is carried in the blood stream, lodging in a small vessel, and obstructing flow

endothelium : the monocellular lining of blood vessels, heart and lymphatic system

exercise tolerance testing: stress test, a diagnostic test in which the patient exercises on a treadmill, bicycle, or other equipment while heart activity is monitored by an ECG.

F

FFP: fresh frozen plasma; the non-cellular component of donor blood that is removed and frozen for later transfusion to treat hypocoagulable states

fibrin : the insoluble protein formed in the blood to form clot by the action of thrombin on fibrinogen

fibrinogen : the protein produced in the liver, present in the blood that is the precursor to fibrin in the clotting process

G

great vessels: the large arteries arising from the heart

H

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HCTZ: hydrochlorothiazide, (type of diuretic)

hematocrit : the percent of the blood which is erythrocytes, normally 35 - 43 %

hemoconcentration: the process of removing fluid from the blood to increase the concentration of hemoglobin and red blood cells

hemodilution: the decrease in the concentration of hemoglobin and red blood cells in the blood

hemodynamic instability: instability of the blood pressure.

hemoglobin : the red pigmented complex protein found in the red blood cells that functions to carry oxygen and carbon dioxide

hemolysis : the freeing of hemoglobin from the inside of the red blood cell by normal breakdown or mechanical destruction

hemostasis : the cessation of bleeding through normal coagulation or by procedure

heparin : a negatively charged polysaccharide normally found in lung or gut mucosa that naturally prolongs the time it takes blood to clot by catalyzing anti-thrombin III

hirudin : coagulation inhibitor isolated from leeches; inhibits thrombin without requiring ATIII

HLHS : hyperplastic left heart syndrome; congenital defect characterized by atretic underdeveloped or absent left ventricle

HR: heart rate

HTN: hypertension

hypercapnea : abnormally high CO2 level in the blood, pCO2 > 45 mmHg

hypercholesterolemia : excessive cholesterol in the blood.

hyperlipidemia: excessive quantity of lipids (cholesterol and triglycerides) in the blood.

Hypertrophic Cardiomyopathy: a condition of abnormally thickened myocardium, leading to diastolic and/or systolic dysfunction

hypertrophy : enlargement of tissue (myocardium) due to the increased size of its cells

hypervolemia : blood volume increased above normal

hypoperfusion : decreased blood flow to an organ or tissue such as in shock

hypotension : decrease of systolic and diastolic blood pressure below normal.

hypovolemia: decreased blood volume below normal

hypoxemia: reduction of oxygen level in the blood below normal

hypoxia : reduction of oxygen level in tissues below normal

I IABP: intra aortic balloon pump; a device inserted thru the femoral artery into the aorta to assist the heart in conditions such as cardiogenic shock. ICA:

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internal carotid artery ICS:

intercostal space

ICU: intensive care unit IDDM:

insulin dependent diabetes mellitus interstitial:

“between cells”; the space in the tissues between cells, outside the vascular system intra-aortic balloon pump :

Use of a balloon catheter inserted through the femoral artery into the descending thoracic aorta to assist the heart in conditions such as cardiogenic shock

coronary stenting: use of a prosthetic metal device to provide and maintain an enlarged coronary lumen at the site of obstructive plaque

I&O (I/O): intake and output; the measurement of patients’ daily intake and output of fluids

ischemia: the state in which tissue oxygen need exceeds supply, leading to cellular damage and possible necrosis

ischemic heart disease: a form of heart disease whose primary manifestations result from ischemia/necrosis due to atherosclerosis of the coronary arteries

IV: intravenous

IVC: inferior vena cava

IVCD: interventricular conduction defect

J JVD:

jugular venous distention JVP: jugular venous pulse K

KVO:

keep vein open

L LA:

left atrium LAD:

left anterior descending coronary artery LBBB:

left bundle branch block LDH:

lactate dehydrogenase, a muscle enzyme, measured in serum to detect muscle damage, especially in myocardial infarction left ventricular function:

function of the main pumping chamber of the heart (left ventricle) that receives left main (LM) disease:

stenosis of the left main (LM) coronary artery.

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LIMA : left internal mammary artery, used as a bypass graft in coronary disease

LLL: left lower lobe

LM: left main coronary artery.

LV: left ventricle

LVH: left ventricualr hypertrophy

Lown-Ganong-Levine: pre-excitation syndrome with shortened PR interval and normal QRS complex. Associated with increased liklihood of supraventricular tachycardia

M

MAP: mean arterial pressure

MB: myocardial band; that portion of the serum CPK due to myocardial damage

mediastinum : The space between the sternum in front and the vertebral column behind, containing the heart and its large vessels, trachea, esophagus, thymus, lymph nodes, and other structures and tissues

MI: 1. mitral insufficiency; back flow or regurgitation of flow through the mitral valve during ventricular systole 2. myocardial infarction

MICU: medical intensive care unit

mitral : the valve separating the left atrium and left ventricle mitral regurgitation : abnormal flow of blood from the left ventricle into the left atrium during sysole mitral stenosis :

mitral valvular stenosis; narrowing of the mitral valve causing a pressure drop or gradient across the valve during left ventricular filling

MR: mitral regurgitation

MS: mitral stenosis

MUGA: multiple gated acquisition test; a radionuclide test of myocardial performance

multivessel disease: disease in two or more of the coronary arteries

MV : mitral valve

MVR: mitral valve repair, or replacement; open heart surgery to repair or replace a diseased mitral valve

myocardial ischemia: condition in which oxygen demand exceeds supply.

myocardial infarction (Ml): damage to the heart muscle caused by occlusion of one or more of the coronary arteries.

myocardium : the muscular wall of the heart

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N

NIDDM: non-insulin dependent diabetes mellitus

nitrate: a drug whose metabolites produce relaxation of vascular smooth muscle, causing dilation of the vasculature

NICU: neonatal intensive care unit

non-Q-wave myocardial infarction: myocardial infarction that is not associated with the evolution of new Q waves on the ECG.

NSR: normal sinus rhythm

NTG: nitroglycerin

O

obtuse marginal: branches of the circumflex coronary artery

OM1, OM2: obtuse marginal 1 or 2

P PA:

pulmonary artery PAC:

premature atrial contraction PCI:

percutaneous coronary intervention PCW pressure:

pulmonary capillary wedge pressure PDA:

1. patent ductus arteriosus 2. posterior descending coronary artery

PE: 1. pulmonary embolus 2. pulmonary edema 3. peripheral edema

percutaneous transluminal coronary angioplasty (PTCA): compression of an athromatous lesion by inflating an intracoronary balloon catheter to dilate the vessel, generally done in conjunction with placement of a stent

perfusion scan: a test to determine the status of blood flow to an organ.

pericardium : the tough, non-elastic membrane surrounding the heart attached to the great vessels and other anatomical structures in the mediastinum

pericarditis :

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inflamation of the pericardium PFO: patent foramen ovale pharmacologic stress test:

a test to detect myocardial ischemia, using medication as a substitute for exercise PI:

pulmonary insufficiency

PICU: pediatric intensive care unit

PJC: premature junctional contractions

plasmin : the substance found in the blood that digests fibrin, resulting in clot dissolution

plasminogen : the precursor to plasmin that is activated by tissue plasminogen activator (TPA)

platelet : thrombocyte

PND: paroxysmal nocturnal dyspnea

POBA: plain old balloon angioplasty. angioplasty without the use of a stent polycythemia :

a condition characterized by too many red blood cells in the circulation post-Ml angina:

angina occurring from 1 to 60 days after an acute myocardial infarction. PR interval: the interval of time between the onset of the P wave and the onset of the R wave measured on the ECG Prinzmetal's angina:

variant angina, a clinical syndrome of rest pain and reversible ST-segment elevation without subsequent enzyme evidence of acute MI, caused by coronary artery spasm

.PS: pulmonary valve stenosis

PT: prothrombin time, protime

PTCA: percutaneous transluminal coronary angioplasty

PTT: partial thromboplastin time

pulmonary edema: condition, usually acute, but sometimes chronic, where fluid builds up in the lungs. This occurs as a response to left ventricular failure in ischemic heart disease, hypertension, or valve disease.

pulmonary atresia : small or undeveloped pulmonary artery and valve

pulmonary insufficiency : pulmonary valvular incompetence; back flow or regurgitation of flow through the pulmonary valve during ventricular diastole

pulmonary stenosis : pulmonary valvular stenosis; narrowing of the pulmonary valve causing a pressure drop or gradient across the valve during left ventricular systole

PV : pulmonary valve

PVC: premature ventricular contraction

PVD:

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peripheral vascular disease

PVR: 1. pulmonary vascular resistance; resistance to the flow of blood through the pulmonary vascular beds 2. peripheral vascular resistance; resistance to the flow of blood through the peripheral vascular beds 3. pulmonary valve repair, or replacement; open heart surgery to repair or replace a diseased pulmonary valve

Q Q Wave:

The first negative deflection of the QRS complex on the EKG

R RA:

right atrium radionuclide test:

A diagnostic test in which a radioactive substance is injected into the bloodstream and the emitted radioactivity is detected by a scanner; used to visualize the heart and vessels.

RBBB: right bundle branch block

RCA: right coronary artery

re-stenosis: the recurrence of a stenosis

retrograde: against the normal direction of flow

revascularization : restoration, to the extent possible, of normal blood flow to the myocardium by surgical or percutaneous means, with removal or reduction of an obstruction as occurs when CABG or PTCA is performed

RHD: rheumatic heart disease

RIMA: right internal mammary artery; used as a graft during coronary artery bypass surgery

RRR: regular rate and rhythm

RV: right ventricle

RVH: right ventricular hypertrophy

S

SA node: sinoatrial node

SBP: systolic blood pressure

SEM: systolic ejection murmur

shock : acute peripheral circulatory failure due to derangement of circulatory control, loss of circulating fluid, of severe cardiac dysfunction

sinus node : bundle of excitatory tissue found in the right atrium that functions as the pacemaker of the heart

Sinus tach:

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sinus tachycardia stenosis :

a narrowing or blockage of a blood vessel, usually an artery sublingual:

beneath the tongue. supraventricular arrhythmia:

an abnormal heart rhythm that originates in the atria or AV node, ie, above the ventricle SV:

stroke volume SVC:

superior vena cava SVG:

saphenous vein graft SVR:

systemic vascular resistance ([MAP-CVP]/CO) SVT:

supraventricular tachycardia

syncope: a brief loss of consciousness

systole : the period of time during contraction of the ventricles

T Tachycardia: rapid heart rate, above 100 beats per minute (BPM) TAPVR:

total anomalous pulmonary venous return TEE:

transesphogeal echocardiography, echocardiography performed by passing a transducer into the esophogus to visualize the heart and great vessels

Tetralogy of Fallot (TOF): congenital heart condition characterized by; 1. over riding aorta, 2. VSD, 3. RV outflow tract obstruction and, 4. ASD

TGA: transposition of the great arteries

thebesian veins: the small veins terminating in the right sided chambers of the heart, draining the right coronary circulation of the heart

thrombocytopenia: abnormal decrease in number of the blood platelets.

thrombolytic therapy: Pharmacologic treatment with a class of drugs that can lyse or dissolve blood clots.

thrombus : blood clot

tricuspid atresia : small or undeveloped tricuspid valve

TI: tricuspid insufficiency

TIA: transient ischemic attack

TOF: tetralogy of Fallot

TPA: tissue plasminogen activator; a substance that converts plasminogen to plasmin to dissolve clot

TR: tricuspid regurgitation

transvenous pacemaker:

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cardiac pacemaker using a pacing electrode or wire passed through a vein into the chambers of the heart that stimulates and maintains a normal heart rate; may be permanent or temporary

tricuspid valve: the valve between the right atrium and the right ventricle

TS: tricuspid stenosis; stenosis of the tricuspid valve

TV : tricuspid valve

U

UAC: umbilical artery catheter

UO: urine output

unstable angina: angina or chest pain that occurs at rest, has accelerated (more frequent, longer in duration, or lower in threshold), or effort angina that has begun within the past three weeks.

V VAD:

ventricular assist device; a blood propulsion devices to assist the failing right or left ventricle valvuloplasty :

surgical repair of a cardiac valve valvulotomy :

an incision into a stenosed cardiac valve to increase the valve area variant angina:

Prinzmetal's angina, a clinical syndrome of rest pain and reversible ST-segment elevation without subsequent enzyme evidence of acute infarction, caused by spasm of a coronary artery

vasa vasorum: the small blood vessels providing nutrient blood flow to large arteries and veins

vasoconstrict: the arterioles decrease in diameter, restricting blood flow to an organ or portion of the body

vasodilate: the arterioles increase in diameter allowing more blood flow

vena cava (e): the large vein(s) collecting the venous return, and draining into the right atrium

ventriculography: a procedure for visualization of ventricles of the heart by x-ray after injection of a radio opaque contrast dye.

V fib: ventricular fibrillation

Von Willebrand Disease : coagulation disorder caused by lack of or non functional Von Willebrand Factor

VSD: ventricular septal defect

V tach/VT: ventricular tachycardia

W

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WPW Syndrome:

A pre-excitation syndrome due to an abnormal band of conduction tissue between the atria and ventricles, resulting in shortened PR interval, widened QRS interval and a delta wave on the ECG. It predisposes to supraventricular tachycardia

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APPENDIX II - Glossary of Cardiovascular medications ARB (Angiotensin Receptor Blocker ) Action: selective blockade of angiontensin AT1 receptors. Use: HTN, MI (acute and post MI), CHF Drug Names: Losartan, Candesartan, Valsartan (AKA:Cozaar, Atacand, Diovan), etc ACEI (Angiotensin Converting Enzyme Inhibitor) Action: Inhibits ACE, blocking conversion of angiotensin I to angiotensin II Use: HTN, MI (acute and post MI), CHF Drug Names: Captopril, Lisinopril, etc. Anti-arrhythmics Action: Mechanisms of action vary Use: For correction of abnormal heart rhythms, tachycardia or premature beats. Drug Names: Amiodarone, Lidocaine, Quinidine, Sotalol, Beta Blockers and Calcium Channel Blockers Anti-Platelets Action: Inhibition of platelet aggregation Use: Acute Coronary Syndrome, atherosclerosis, stroke prophylaxis, thromboembolism prophylaxis, percutaneous coronary

intervention, intermittent claudication Drug Names: Aspirin, Dypridamole, Clopidogrel, Ticlodipine Anticoagulants/Thrombolytics Action: Inhibition of clot formation/Dissolution of Clots Use: DVT, pulmonary embolism, MI, Stroke Drug Names: Heparin, Enoxaparin, Warfarin, Tenecteplase, Alteplase, etc. Antihypertensives Action: Primarily induction of peripheral vessel dilation Use: HTN, CHF, hypertensive emergency Drug Names: Doxazosin, Prazosin, Clonidine, Hydralazine, Nitroprusside, etc. Beta Blockers Action: Block adrenergic receptors Use: MI, HTN, angina, arrhythmias Drug Names: Atenolol, Metoprolol, Propanolol, etc. Calcium Channel Blockers Action: blockade of Ca2+ influx, producing vasodilation. Some also slow heart, reduce arrhythmias, and reduce inotropy Use: HTN, angina, arrhythmias Drug Names: Amlodipine, Nifedipine, Verapamil, Diltiazem, etc. Cholesterol Lowering Agents Action: Lower LDL, TG or increase HDL through various mechanisms Use: Hypercholesterolemia, hypertriglyceridemia, 2° prevention of CV events Drug Names: Lovostatin, Simvistatin, Cholestyramine, Gemfibrozil, Niacin, etc. Diuretics Action: Decrease plasma volume and total peripheral resistance through various mechanisms Use: HTN, CHF, edema Drug Names: Hydrochlorothiazide, Furosemide, Spironolactone, Triamterene, etc. Inotropes/Pressors Action: Primarily stimulation of adrenergic receptors

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Use: CHF, shock, cardiac arrest Drug Names: Dobutamine, Dopamine, Phenylephrine, Milrinone, Epinephrine, etc. Digoxin is an oral inotropic agent, but has no pressor action. Nitrates Action: Induction of vascular smooth muscle relaxation Use: Acute angina, angina prophylaxis Drug Names: Nitroglycerine, Isosorbide Dinitrate, etc.

practice of medicine ii cardiovascular text 2008...

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