Cardiac Medications
By Theresa Till RN, Ed.D, CCRN
The Intima Controls the Destiny of the Cardiovascular
System
Atherosclerosis
Atherosclerosis results from the interaction between the intimal surface (endothelium), WBCs (macrophages), and fat (lipoprotein).
http://www.youtube.com/watch?v=n8P3n6GKBSY
http://www.youtube.com/watch?v=qRK7-DCDKEA&NR=1
Macrophage on Intima The macrophage
determines that the fat on the intima is foreign and sends WBCs to the surface to destroy the fat. However, the intima is frequently also damaged.
Blood Vessel Layers
http://www.youtube.com/watch?v=zeS-0au8ij4&NR=1&feature=fvwp
Antiplatelets
Decrease afterload because they cause the cells to be less sticky.
http://www.youtube.com/watch?v=YcNYxegDXa8
Platelet Activation
Clotting Cycle
Heparin
Route: IV or SQ Onset: Immediate Duration: hours (about 4) Monitor: APTT, anti-Xa Antidote: Protamine Sulfate
Heparin-Induced Thrombocytopenia (HIT)
12 million patients exposed to heparin each year.
Consider HIT whenever a hospitalized patient exposed to heparin experiences a drop in platelet count or develops new thrombi.
HIT results in thrombosis despite anticoagulation due to immune complex aggregation in blood despite low or reduced platelet counts.
Patients lose unaffected extremity due to thrombosis (fractured ankle, lose hand).
Definition of HIT
Thrombocytopenia: ≤ 150,000 50% drop in platelet count from
baseline (can still be within normal range and have HIT)
Platelet recovery once UFH/LMWH stopped
Patient with or without thrombosis
Treatment for HIT Stop heparin product Give direct thrombin inhibitor
bivalirudin (Angiomax) lepirudin (Refludan) Argatroban (Acova)
Fondaparinux (Arixtra) Once platelet count recovers, put
patient on Coumadin.
Coumadin Route: Oral Onset: Slow (hours) Duration: Days Monitor: PT, INR Antidote: Vitamin K Keep dietary intake of Vitamin
K consistent.
Properties of the Heart
Inotropic (strength of cardiac contraction)
Chronotropic (rate of cardiac contraction)
Dromotropic (electrical excitability of the heart)
Hemodynamics of the Heart Preload –amount of fluid in ventricles
immediately before contraction.
Afterload- amount of resistance the heart has to overcome to eject blood into the circulatory system.
Contractility- amount of heart stretch
Preload
Patients in HF have an increased preload.
This increased fluid in the chambers of the heart result in increased stretching of the muscle.
Degree of stretching can be measured by the BNP (Brain Naturetic Peptide).
Blood test BNP > 100 suggestive of HF
http://www.youtube.com/watch?v=GnpLm9fzYxU
HypertensionGuidelines
Category SBP DBPNormal <120 <80Pre-HTN 120-139 80-89HTN (1) 140-159 90-99HTN (2) >160 >100
HTN
2X risk of CVA, MI if patient 20/10 over goal.
4X risk of CVA, MI if patient 30/20 over goal.
Using combination therapy much sooner.
“Dipper v. Non-Dipper”
Important to take BP different times during day----even at night.
Normally, BP reduces when a person sleeps.
However, some people have a BP that remains high throughout the day, which increases the risk of coronary artery disease.
Diuretics and Renal Absorption
Nitrates
Tolerance is a “big” issue
Safety is a big issue since they are powerful preload and afterload reducers (dilate blood vessels and drop BP)
Renin Angiotensin Aldosterone System (RAA)
Renin/Angiotensin System
Renin Angiotensin I Angiotensin II (vasoconstriction)
Aldosterone release from adrenals
(sodium retention, potassium excretion and fluid retention).
Opposite occurs with ACEI because block Angiotensin II so loose sodium/fluid and retain potassium.
Renin/Angiotensin/Aldosterone (RAA) System
Angiotensin I converts to Angiotensin II which causes VASOCONSTRICTION
Next, aldosterone is released that results in sodium retention and potassium excretion.
When ACE inhibitors block the renin/angiotensin system, sodium is released and potassium is absorbed.
Check for hyperkalemia.
Ace Inhibitors
Preload reducer (decreases venous volume)
Afterload reducer (decreases arterial volume)
Diuretic
ACE Inhibitors
Renin-angiotensin-aldosterone system (RAAS):
http://pearsonium.com/RAASystem/index.html
Calcium Channel Blockers
Block the calcium influx into the blood vessel thus preventing actin and myosin from sliding over each other.
Net vasodilation Also, great for Prinzmetal angina
(spasm). Some are powerful dysrhythmics
Calcium Channel BlockersActin/Myosin
Beta Blockers
Decreases Heart Rate (Blunts HR) Decreases Heart Contraction Decreases Excitability of Heart
CARE WITH DIABETICS AND ASTHMATICS
Cholesterol
Remember that cholesterol can be elevated if a person is hypothyroid.
Physicians should do a thyroid panel (T3,T4, TSH) before starting a patient on hypolipemics.
Many times once the thyroid problem is corrected, the cholesterol returns to normal.
New Statin GuidelinesACC/AHA
Individuals who need statins are Diabetics History of Heart Disease LDL >1 90 •Patients with an estimated 10-year risk
of cardiovascular disease of 7.5 percent or higher who are between 40 and 75 years of age (the report provides formulas for calculating 10-year risk).
New Statin Guidelines Websites
http://circ.ahajournals.org/content/early/2013/11/11/01.cir.0000437738.63853.7a.full.pdf
Research article explaining new guidelines
http://my.americanheart.org/professional/StatementsGuidelines/Prevention-Guidelines_UCM_457698_SubHomePage.jsp
Calculator
http://newsroom.heart.org/news/acc-aha-publish-new-guideline-for-management-of-blood-cholesterol
Guidelines
Controversy Regarding “Statin” Guidelines http://www.doctoroz.com/episode/controversia
l-new-statin-guidelines Part 1
http://www.doctoroz.com/episode/controversial-new-statin-guidelines?video_id=2859817307001 Part 2
Cholesterol
HDL/LDL Ratio
Hyperlipidemia
Total Cholesterol Want < 200 HDL “Good Fat” Want >40 M >50 F LDL “Bad Fat” Want < 130 if healthy
Want < 100 if high risk (some MD want ≤ 70)
Triglycerides Want < 150
Hypothyroidism can lead to increased cholesterol.
TC/HDL Ratio Want < 4.5
TC/HDL Ratio
Examples: Patient A: Total cholesterol 240, HDL 80 240/80 =3 (Low Risk for CAD) Patient B: Total Cholesterol 240, HDL 30 240/30= 8 (High Risk for CAD)
Metabolic Syndrome
Clustering of obesity, dyslipidemia, hypertension, and insulin resistance exponentially increase the risk of CAD.
http://www.oprah.com/oprahshow/Dr-Oz-Explains-What-Diabetes-Does-to-Your-Body-Video
Metabolic Syndrome(continued)
Three of five = increased risk of CAD Waist circumference M >40” and
F >35” TG > 150 HDL Men <40 Women <50 BP > 130/85 Fasting blood sugar >110
Dysrhythmics
http://www.youtube.com/watch?v=XV11kplLoxw&feature=related
http://www.youtube.com/watch?v=xLzRFAT9uFA
Normal Electrical Conduction System through the HeartWhen impulses do not travel normal electrical pathway, dysrhythmias occur.
Electrical System
1)P Wave = atrial contraction2) PR Interval = 0.12-0.20 (SA Node → AV Node)3) QRS complex =ventricular contraction (≤ 0.12)4) ST segment (should be flat or isoelectric)5) T wave = ventricular relaxation6) QT Interval = ventricular contraction and relaxation (≤
0. 40)
Smoking Disconnect remains between trial
evidence and clinical practice. 25% of Americans smoke yet
people have known since the 1960s that smoking causes cancer.
Cardiologists are writing “no smoking” prescriptions to reinforce importance of abstinence.
