Heart Failure

Heart failure in infants and children are often associated with congenital heart disease. Signs and symptoms usually occur in 1st year of life. Occasionally there may be non-cardiac causes (anaemia, fluid overload, thyrotoxicosis). Heart failure often gets incorrectly diagnosed as pneumonia. 

Causes can be divided into 

• Volume overload: L-R shunt lesions or mitral/aortic regurgitation 
• Pump failure: myocarditis/cardiomyopathy 
• High output failure: septicaemia or severe anaemia 

Clinical features 

• Failure to thrive or excessive sudden weight gain 
• Breathlessness 
• Sweating 
• Poor feeding 
• Irritable and inconsolable 
• Shock 
• Decreased effort tolerance (older children) 

Signs: 

• Tachycardia 
• Hypotension, cool peripheries 
• Poor peripheral perfusion / poor volume pulses 
• Periorbital oedema (Peripheral oedema is NOT a common sign in children) 
• Underweight for age or abnormal weight gain 
• Gallop rhythm with/without a cardiac murmur 
• Tachypnoea, dyspnoea, orthopnoea, recession, wheezing, basal crepitations, cyanosis 
• Hepatomegaly 
• Reduced urinary output 

Causes of heart failure in children

Investigations 

• Bloods: 
  • FBC / U & E / consider cardiac enzymes if myocarditis a concern 
  • ASOT + Anti-DNase B (Rheumatic Fever) 
  • Thyroid Functions 
• CXR: 
  • Cardiomegaly, plethoric lung fields, abnormal heart shape 
• ECG: 
  • Ventricular Hypertrophy, Atrial enlargement, Arrhythmias 
• Echo: 
  • Assessment of Structure and function of heart 

Management 

• Recognise and treat the underlying condition, e.g. infection, hypertension, cardiac tamponade, fluid overload. 
• Oxygen via face mask, nasal cannula to prevent hypoxia (In child keep sats > 92% at least) 
• Fluid restriction (75% of daily requirements) – not at expense of adequate caloric intake 
• Ensure adequate nutrition, tube-feeding may be necessary 
• Try not to upset the child further – examine with parent present or even on parent’s lap. 
• Use EMLA cream prior to venepuncture. 

Drug treatment: 

Combination drug therapy is usually indicated. Start with diuretics and only if required, add an ACE inhibitor. Digoxin is becoming controversial, get advice from expert before use. 

Diuretic therapy 

• Furosemide IV/PO, 1–3 mg/kg/24 hours in 2–3 divided doses 
• Spironolactone PO, 2–4 mg/kg/24 hours in 2 divided doses 

Side effects: Hypokalaemia, hypochloremic alkalosis – may increase digitalis toxicity 

Monitor blood potassium levels. Potassium supplements are necessary if furosemide is used without an aldosterone antagonist, i.e. spironolactone. 

ACE inhibitor 

• Captopril oral, 0.5 mg/kg/24 hours in 3 divided doses (8 hourly) for 24–48 hours – initial dose, Increase by 0.5 mg/kg/24 hours every 24–48 hours until maintenance dose of 3–5 mg/kg/24 hours is reached. 

Used for afterload reduction. Consider in persistent heart failure where other measures have failed, only after consultation with a paediatrician or paediatric cardiologist. Monitor blood potassium levels and consider stopping potassium supplements while patient is on an ACE inhibitor. Note: ACE inhibitors are contraindicated in bilateral renal artery stenosis, coarctation of the aorta and aortic stenosis. 

Digoxin 

Only use in consultation with a cardiologist. Digoxin is contraindicated in bradycardia, heart block, cardiac tamponade or hypertrophic cardiomyopathy. Monitor serum potassium and digoxin blood levels and ECG. Intravenous digoxin is dangerous and inappropriate. 

Severe / acute heart failure (with pulmonary oedema)

1. Treat the underlying disorder/condition. Where the primary cause of acute pulmonary oedema is renal failure treat as under renal failure. 

2. Beware of giving fluid bolus if in cardiac failure as this may result in pulmonary oedema. Restrict fluids to 60ml/kg/day, beware of IV fluids. 

3. Oxygen 100%, administered via face mask or nasal cannula. Place patient in an upright or semi-upright sitting position. 

4. Diuretics: Furosemide 1-2 mg/kg IV slowly over 10 min. May even need to increase to 4 mg/kg IV. (Lasix should be given slow IV as rapid bolus may be associated with deafness!) 

5. If Hb < 8mg/dl may need blood transfusion with 5-10 ml/kg/d over 6hrs IV aliquots and reassessing the ability to handle the extra fluid, with extra Furosemide 1mg/kg. 

6. Intensive care support – call senior for advice and assistance. Inotropic support may help to stabilise patients with severe myocardial dysfunction, hypotension or low cardiac output. May be lifesaving in severe myocarditis or cardiogenic shock. Start with low dose Dobutamine, IV infusion, 2–15 mcg/kg/minute. Continue until myocardial function and blood pressure improve. Low dose dobutamine is the initial inotrope of choice as it can be given in a peripheral line and is both a +ve inotrope and a vasodilator allowing for afterload reduction and perfusion of kidneys.