Paediatrics: Heart failure

Heart failure

Heart failure may be manifested by symptoms of poor tissue perfusion alone (e.g. fatigue, poor exercise tolerance, confusion) and/or by symp-toms of congestion of circulation (e.g. dyspnoea, pleural effusion, pul-monary oedema, hepatomegaly, peripheral oedema), without evoking compensatory mechanisms.

The underlying pathophysiology mechanisms that lead to compromise of cardiac stroke volume, cardiac decompensation, and heart failure include:

•   increased afterload (pressure work);

•   increased preload (volume work);

•   myocardial abnormalities;

•   tachyarrhythmias.

Causes of heart failure

In children the most common cause of heart failure is congenital structural defects of the heart.

•   Large left to right shunt: e.g. large VSD (not in first few days of life).

•   Left-sided obstructive lesions: coarctation of aorta; hypoplastic left side of heart (within first few days of life).

•   Cardiomyopathy: hypertrophic; dilated; restrictive.

•   Myocarditis: viral; rheumatic fever.

•   Endocarditis.

•   Myocardial ischaemia: anomalous left coronary artery; Kawasaki disease.

•   Tachyarrhythmias: supraventricular tachycardia.

•   Acute hypertension.

•   High-output: severe anaemia; thyrotoxicosis; AV malformations.

Clinical features

The clinical features of heart failure depend on the degree of cardiac reserve. The most common symptoms and signs are those in keeping with increased compensatory sympathetic drive:

• sweating;

• breathlessness, tachypnoea, coughing, lung crepitations;

• poor feeding (infant), poor weight gain, and failure to thrive;

• hepatomegaly;

• cardiomegaly;

• tachycardia/’gallop’ heart rhythm.

There are usually few signs of systemic congestion as observed in adults. Only children with chronic heart failure, or adolescents, may have ‘adult’ signs such as oedema, orthopnoea, paroxysmal nocturnal dyspnoea, ankle oedema and elevated JVP.

Investigations

These are directed at finding a cause and quantifying function.

• Chest radiograph:

o cardiac enlargement;

o lungs—oligaemic/oedema.

• Echocardiography: congenital heart defects.

• Arterial blood gas: reduced PO₂/metabolic acidosis.

• ECG: not diagnostic, but may assist in establishing aetiology.

• Serum electrolytes: hyponatraemia due to water retention.

Management

The underlying cause of heart failure must be treated.

General measures

• Bed rest and nurse in semi-upright position: infants in chair/seat.

• Supplemental oxygen (not in left to right shunt).

• Diet: sufficient calorie intake.

• Diuretics.

Angiotensin converting enzyme inhibitors.