Heart Failure in ChildhoodHusna Najihah Dzulkarnain1213828

Contents

• Definition• Epidemiology• Pathophysiology• Causes• Clinical Features• Investigations• Management• Differential diagnosis

Definition

• Childhood: period from birth to being adolescents.

• Heart Failure is defined as the inability to provide adequate cardiac output to meet the metabolic demand of body.

( Nelson Textbook of Paediatrics, 19th edition)

Epidemiology

• Worldwide, congenital heart disease is the most common cause of pediatrics heart failure, followed by cardiomyopathy.

• CHD occurs in around 8 per 1000 live births, however, many of these children receive early surgical intervention and it has been estimated that the yearly incidence of heart failure as a result of congenital defects is between 1 and 2 per 1000 live births.

• Malaysia?

Why is it important?

• Childhood-a period of rapid growth, and high energy, nutrients need to be supplied adequately.

• Slower growth and development• Complications-emotional issues ,lifelong management

(follow up in CHD)

Physiology of the heart

Cardiac Output

Cardiac output = Heart Rate x Stroke volume

• Afterload• Preload• Contractility

(intrinsic myocardial function)

• Tachyarrhythmia-shorten the diastolic time interval for ventricular filling.

Physiology of the heart

Pressure-volume relationship

Normal heart

• In a healthy heart, the increase in preload which consequently increase in the ventricular end-diastolic volume will cause the augmentation of cardiac output.

• The increased stroke volume in this manner is possible due to the stretching of myocardial fibers which also result in increased wall tension.

Compensatory mechanism

• Frank-Starling Mechanism- The increased volume of blood stretches the

ventricular wall, causing cardiac muscle to contract more forcefully.

• Neurohormonal System activation

• Sympathoadrenal axis- increase in sympathetic tone secondary to

increase adrenal secretion of circulating epinephrine and increased

neural release of norepinephrine.

• Initially, increase heart rate and myocardial contractility.

• Later, hypermetabolism, increased afterload, arrythmogenesis,

increased myocardial oxygen requirements, and direct myocardial

toxicity.

• Activation of RAAS

• Myocardial structural changes-dilatation or hypertrophy

Compensatory mechanism

Pathophysiology

Low Output Failure

High Output Failure

Cardiac Output

Cardiac output = Heart Rate x Stroke volume

• Afterload• Preload• Contractility

(intrinsic myocardial function)

• Tachyarrhythmia-shorten the diastolic time interval for ventricular filling.

Preload and afterload

Heart Failure

• Myocontractility : cardiac muscle with a compromised intrinsic contractility requires a greater degree of dilatation to produce an increased stroke volume, and does not achieve the same maximal CO as normal myocardium

• Preload : If a dilated chamber is already dilated because of a lesion causing an increased preload (e.g: left to right shunt or valvular insufficiency) , there is only a little room left for further dilatation and augmentation of CO.

• Afterload : the presence of lesions that results in increased afterload to the ventricel (e.g: aortic or pulmonic stenosis, coarctation of aorta) decreases cardiac performance, leading to reduced CO.

• Abnormal rhythms : Tachyarrhythmia shorten the diastolic time interval for ventricular filling.

High output cardiac failure

• The CO is normal or increased, but because of

decreased systemic oxygen content (secondary to

anemia) or increased oxygen demand (secondary to

hyperventilation, hyperthyroidism, or

hypermetabolism), there is an inadequate amount of

oxygen delivered to meet the body’s needs.

• This will result in development of signs and symptoms

of heart failure when there is no basic abnormality in

myocardial function and the CO is greater

than normal.

Causes

• Congenital• Acquired

Causes

• Left to right shunt lesions : VSD,PDA,AVSD,ASD• Obstructive left heart lesions: Hypoplastic left

heart syndrome, coarctation of aorta, aortic stenosis• Common mixing unrestricted pulmonary flow :

Truncus arteriosus, TAPVD, tricuspid atresia, TGA, single ventricle, pulmonary atresia with VSD,large aortopulmonary collateral

• Valvular regurgitation: AV valve regurgitation, Eibstein anomaly, semilunar valve regurgitation

• Myocardial Ischemia : anomalous origin of left coronary artery from pulmonary artery.

Congenital

Causes

• Acquired valvular disease : chronic rheumatic valvular disease, post infective endocarditis

• Myocardial disease

Acquired

Causes: Myocardial disease (Acquired)

• Effect the heart’s contractility.

Primary cardiomyopath

y:

• Idiopathic• Familial

Secondary cardiomyopathy:

• Arrythmia-induced: congenital heart block, atrial etopic tachycardia

• Infection: post viral myocarditis, Chagas disease.

• Ischemic: Kawasaki disease• Myopathic : muscular

dystrophy• Pompe disease ,

mitochondrial disease• Metabolic: hypothyroidism• Drug-induced: anthtracycline• Others: iron overload

(thalassemia)

Acute myocarditi

s:

• Viral• Rheumatic• Kawasaki

disease

Etiology according to age group

• Fetal:

• Severe anemia (hemolysis,fetal-maternal

transfusion,parvovirus B19-induced

anemia,hypoplastic anemia)

• Supraventricular tachycardia

• Ventricular tachycardia

• Complete heart block

Premature Neonate:Fluid overloadPDAVSDCor Pulmonale

(bronchopulmonary dysplasia)

• Full-term neonate• Asphyxial cardiomyopathy• AVM• Left-sided obstructive lesions (coarctation of

aorta, hypoplastic left side of the heart)• Large mixing cardiac defects (single

ventricle,truncus arteriosus)• Viral myocarditis

Infant-ToddlerLeft-to-right cardiac shunts (VSD)HemangiomaAnomalous left coronary arteryMetabolic cardiomyopathyAcute hypertension (HUS)SVTKawasaki’s disease

• Child-adolescent• Rheumatic fever• Acute hypertension (glomerulonephritis)• Viral myocarditis• Thyrotoxicosis• Hemochromatosis-hemosiderosis• Cancer therapy • Sickle-cell anemia• Endocarditis• Cor pulmonale (cystic fibrosis)• Cardiomyopathy

Complications

• Metabolic acidosis• Cardiogenic shock

Approach to patient

• History• Physical Examination• Investigation• Treatment

History

• NEONATES & INFANTS • Poor feeding

• Tachypnoea worsening during feeding

• Sweating during feeding

• Poor weight gain

• Irritable

• Weak cry

• Wheezing

• Labored breathing

• Recurrent chest infections

• OLDER CHILDREN• Fatigue

• Exercise intolerance

• Dyspnoea –pulmonary congestion

• Pedal edema

• Growth failure

Physical Examination

1) Poor perfusion- cool extremities,

decreased capillary refill, decreased

peripheral pulses, and low systemic

blood pressure.

2) Pulmonary congestion- resting

tachypnea, respiratory distress (chest

retractions, use of accessory muscles,

infants with gruntings and nasal flaring).

Wheezing and crepitation are more

common in older children

3) Systemic congestion – hepatomegaly,

raised JVP (usually not in infants and

younger children), peripheral edema.

Others

• High blood pressure limited to upper extremities and/or feeble pulses in lower extremities are suggestive of aortic coarctation

• The presence of a systolic murmur may be seen in patients with outflow obstruction in hypertropic cardiomyopathy or aortic stenosis, congenital heart defects with left-to-right shunting (eg, ventricular septal defects), or mitral regurgitation.

• Precordial examination may reveal a “thrill” in patients with shunt lesions, whereas those with a long-standing cardiomyopathy may have a “heave” with a laterally displaced point of maximal impulse.

Investigation

• Blood tests• Chest X-Ray• ECG• Echocardiography• Doppler ultrasound

Blood Tests

1) Full blood count-anemia, leukocytosis

2) Liver function tests –elevated due to hepatic congestion with right-sided heart failure.

3) Serum electrolytes, blood urea nitrogen, and creatinine.

• Hyponatremia due to water retention.

• Hyperkalemia may represent tissue destruction due to low CO or renal compromises.

• High BUN and creatinine due to reduced RBF may suggest renal impairment.* Brain natriuretic peptide (BNP) - cardiac hormone

secreted by the ventricular cells in response to increased wall stress in volume or pressure overload

Chest X-Ray

e.g: Ventricular Septal Defect

Case courtesy of Dr Frank Gaillard, Radiopaedia.org

Findings:

• Cardiomegaly

• Pulmonary edema

ECG

• Sinus tachycardia• Varying degrees of heart block may sometimes

be observed in patients with rheumatic or lyme carditis, or in patients with neonatal lupus.

• Increased QRS voltage that meets criteria for ventricular hypertrophy may be seen in hypertrophic or dilated cardiomyopathy

• Decreased QRS voltage may suggest myocardial edema or pericardial effusion, and may be present in children with myocarditis

Transthoracic Echocardiography (TTE)

• Assess ventricular function

Fractional shortening

Cardiac output

“Eyeballing“ of LVF Cardiac Index

Ejection fraction (EF) - Simpson method

Contractility (dp/dt)

Stroke volume Tei index

• lower cost, less risk, and greater availability compared with cardiac magnetic resonance imaging or cardiac catheterization

Doppler ultrasound

• Estimate cardiac output• Assess cardiac function, wall motion abnormalities as it

records motion of blood inside the heart.• Obstruction in arteries• Measure degree of narrowing or leakage of heart valve

Management

• Aim:• Treat underlying causes• enhancing cardiac contractility• reducing the preload and afterload• improving oxygen delivery

Management- General Measures

• Oxygen supplementation, keep in propped up position

• Keep warm, gentle handling• Fluid restriction to ¾ normal maintenance if

not dehydrated• Correct anemia, electrolyte imbalance, treat

concomittant chest infections.• Diets-increased daily calorie intakes

• Total daily fluid requirement = Normal Maintenance Fluids + Deficit + Ongoing Abnormal Losses

•  Factors that increase caloric requirements: Similar to adults, certain factors will increase daily caloric requirements in children.

AGE (yrs)

Kcal/kg/day

0 - 1 90 - 120

1 - 7 75 - 90

7 - 12 60 - 75

12 - 18 30 - 60

FACTOR INCREASE IN CALORIC NEED2

Fever 10 - 12 % for each degree > 37o C

Cardiac failure 15 - 25 %

Major surgery 20 - 30 %

Burns up to 100 %

Severe sepsis 40 - 50 %

Long term growth failure 50 - 100 %

Anti Failure Medications

• Diuretics –increased water and sodium loss, providing symptomatic relief in fluid overload• Loop diuretics (more powerful agents than thiazide)-

frusemide, bumetanide• Spironolactone-potassium-sparing diuretics, aldosterone

antagonist• ACE inhibitor : afterload-reducing agent, by

decreasing peripheral vascular resistance.• Captopril-greater stability in liquid formulation• Enalapril-require less frequent dosing

• Digoxin-useful in HF with excessive tachycardia, SVT• IV inotropic agents- dopamine, dobutamine,

adrenaline, milrinone• Use in acute HF, cardiogenic shock, post-op low output

syndrome

Specific management

• Aetiology establishment• Specific treatment for targeted aetiology• Congenital-surgery• Heart block- pacemaker• Post infectious glomerulonephritis- control BP• Acute rheumatic carditis – High dose aspirin

Mnemonic for management

Differential Diagnosis

• Respiratory distress

• Neonates-Respiratory distress syndrome, transient tachypnea of the newborn, meconium aspiration, congenital diaphragmatic hernia, pneumothorax, pneumonia, and pulmonary hypoplasia.

• Older infants and children – Pneumonia, asthma, and gastroesophageal reflux.

• Poor weight gain and FTT- Gastrointestinal causes include protein-milk allergy, cystic fibrosis, and celiac disease, Chronic infections, Hyperthyroidism, Metabolic disorders

• Fatigue in older children may be due to sleep apnea, depression

• Peripheral edema may be caused by renal failure or venous thrombosis

• Shock may be due to overwhelming sepsis or hypovolemia

References

• Nelson Textbook of Pediatric, 16th edition• Paediatric Protocols, 3rd edition• Heart Failure in children and young adults, Anthony

C.Chang, Jeffrey A.Towbin

Thank You !