PAEDIATRIC HEART DISEASE

•	Congestive cardiac failure.
•	Cardiac arrhythmias.
•	Infections.
•	Disease of the myocardium.
•	Associated syndromes

Congestive cardiac failure

1.	Cardiac failure occurs when the heart is unable to pump sufficient blood for the body’s requirements.

2.	Symptoms

a.	Failure to thrive.

b.	Feeding problems.

c.	Fatigue, easy tiring.

d.	Dyspnoea.

e.	Recurrent chest infections.

3.	Signs

a.	Cardiomegaly.

b.	Tachycardia.

c.	Tachypnoea.

d.	Hepatomegaly.

e.	Gallop rhythm.

f.	Creps in lung bases.

g.	Poor pulses and peripheral vasoconstriction.

h.	Peripheral edema and ascites.

I.	Raised JVP.

4.	Signs of vascular collapse

a.	Absent pulses.

b.	Mottled extremitis.

c.	Hypothermia.

d.	Gasping respiration.

e.	Reduced urine output. 

5.	Common causes of CCF in different age groups

Age group	Causes	
Fetus	•	Severe anaemia: hemolysis, fetal-maternal transfusion.
•	Supraventricular tachycardia.
•	Ventricular tachycardia.
•	Complete heart block.	
Premature neonate	•	Fluid overload.
•	PDA.
•	VSD.
•	Cor pulmonale.	
Full-term neonate	•	Asphyxial cardiomyopathy.
•	AVM (vein of Galen).
•	Coarctation of aorta.
•	Hypoplastic left heart.
•	TGA.
•	Single ventricle.
•	Truncus arteriosus.
•	Viral myocarditis.	
Infant-toddler	•	VSD.
•	ASD.
•	Haemangioma.
•	Acute hypertension in haemolytic-uraemic syndrome.
•	Supraventricular tachycardia.
•	Kawasaki disease.	
Child-adolescent	•	Rheumatic fever.
•	Acute hypertension due to GN.
•	Viral myocarditis.
•	Thyrotoxicosis.
•	Endocarditis.
•	Cor pulmonale (cystic fibrosis).	

6.	Principles of Treatment

a.	General measures:

i.	rest +/- morphine.

ii.	temperature and humidity control in neonates.

iii.	100% oxygen.

iv.	diet: high calorie, low Na, nasogastric feeding.

v.	fluid restriction to 100 – 120 ml/kg.

b.	Medical intervention:

Reduce preload	•	Diuretics: chlorothiazide, frusemide, spironolactone.
•	Vasodilators: nitroprusside, prazosin.	
Reduce afterload	•	Reduce blood viscosity.
•	Arteriolar dilators: hydralazine, captopril, enalapril.	
Increase contractility.	•	Improve physical and metabolic mileu: pH, CO2, glucose, Ca, Hb.
•	Drugs: digoxin, isoproterenol, dopamine, dobutamine.	
Heart rate	•	Cardiac pacing.
•	Anti-arrhythmics.	

c.	Surgical interventions to remove underlying cause. 

7.	Digoxin

a.	Drug of choice for infants and children.

b.	Correct dose for each patient must be individualized as there is considerable variability in the absorption, metabolism, exertion and intracellular electrolyte.

c.	Before giving digoxin, the following should be done:

i.	baseline ECG.

ii.	serum electrolytes esp. K.

iii.	estimation of renal function – blood urea and creatinine. 

d.	Initial digitalization: 4x / day, ½ , ¼, 1/8 and 1/8 oral.

e.	Maintenance dose: 2x / day, 33% dose.

f.	Factors potentiating digoxin toxicity:

i.	hypokalaemia.

ii.	hypercalcaemia.

iii.	cardiac inflammation.

iv.	prematurity.

g.	Treatment of toxicity:

i.	stop the drug.

ii.	gastric lavage and induced emesis.

iii.	digoxin antibody.

iv.	treat cardiac arrhythmias – avoid quinidine, verapamil, amiodarone, administer lignocaine, phenytoin and propranolol.

v.	treat electrolyte disturbances. 

Cardiac Arrhythmias

1.	Mechanism

a.	Re-entrant: an area of electric re-entry within cardiac muscle and conduction, e.g. Wolf-Parkinson-White.

b.	Automatic: spontaneous phase 4 depolarization.

c.	Triggered activity: digoxin intoxication.

2.	Arrhythmias are always associated with abnormal cardiac development.

3.	Causes of arrhythmias

a.	Corrected transposition.

b.	AVSD.

c.	Secondary ASD.

d.	Asplenia and polysplenia syndrome.

e.	MVP.

f.	Ebstein’s anomaly. 

4.	Bradycardia

a.	Pulse rate: 40 – 70 bpm.

b.	Causes:

i.	immaturity.

ii.	post-op atria surgery.

iii.	electrolyte disturbances: hypocalcaemia and hypokalaemia.

iv.	GE reflux.

v.	increased ICP.

vi.	hypothermia.

vii.	hypothyroidism.

c.	Complete heart block

i.	associated lesions: corrected TGA, single ventricle, AVSD, maternal SLE.

ii.	asymptomatic heart failure.

iii.	sudden death. 

5.	Supraventricular tachycardia

a.	Most prevalent.

b.	Need to rule out:

i.	Ebstein’s anomaly.

ii.	corrected TGA.

iii.	HCM.

iv.	any heart defects.

c.	Management:

i.	vagal maneuvers.

ii.	pharmacological: adenosine and verapamil.

iii.	cardioversion.

iv.	radiofrequency catheter ablation.

6.	Long QT syndrome

a.	Children with arrhythmias, congestive heart failure, moycarditis and on quidine, some antibiotics and diuretics are at increased risk of developing LQTS.

b.	Untreated LQTS has a mortality rate of 50%. 

c.	Treatment options include beta-blockers, implantation of a pacemakter and/or defibrillator.

d.	LQTS should be looked for / excluded in any child with breath-holding attacks, seizures precipitated by emotion or exertion, all initial afebrile seizures, unexplained syncope and congenital deafness. 

Rheumatic heart disease

1.	Pathology

a.	Result of an abnormal immune response on the part of the host to certain streptococcal antigens, which results in an autoimmune disorder affecting the heart, synovial membranes and other tissues.

b.	Main sequelae: development of damage to cardiac valves, resulting in the development of mitral stenosis and/or incompetence and aortic stenosis / incompetence.

2.	Epidemiology

a.	Incidence: 3 – 4%.

b.	Commonly occurs between 5 – 15 years.

c.	Equal incidence in both sexes. 

3.	Major criteria:

a.	Migratory polyarthritis mainly affecting large joints.

b.	Evidence of carditis with tachycardia, cardiac enlargement and development of new murmurs.

c.	Sydenham’s chorea: choreiform limb movements.

d.	Erythema marginatum: a transient demarcated skin rash on the trunk.

e.	Development of nodules over bony prominences.

4.	Minor criteria

a.	Fever.

b.	Arthralgia.

c.	Previous history of rheumatic fever.

d.	Raised ESR or CRP.

e.	Prolonged PR interval on ECG.

5.	Diagnosis

a.	Presence of two or more major criteria.

b.	Presence of one major and two minor criteria.

c.	Positive throat culture or antibody titre for streptococcal infection.

6.	Differentials

a.	Viral infections.

b.	Juvenile rheumatoid arthritis.

c.	SLE.

d.	Infective endocarditis.

7.	Treatment

a.	Prevention of initial attacks: treatment of streptococcal pharyngitis with penicillin, erythromycin.

b.	Treatment of acute phase:

i.	course of antibiotics.

ii.	suppression of inflammation with aspirin and steroids.

iii.	bed rest.

iv.	diuretics, salt restriction and digoxin for heart failure.

v.	chorea: sedation.

c.	Prophylaxis for recurrences:

i.	oral penicillin 250 mg BD.

ii.	IM Benzathine Penicillin 1.2 mg 4 weekly.

iii.	age till 25 years / at least 5 years after last attack.

iv.	endocarditis prophylaxis. 

Infective endocarditis

1.	The presence of structural cardiac abnormalities associated with turbulent blood flow within the heart or major arteries predisposes to seeding of bacteria into endocardial lesions.

2.	Symptoms

a.	Fever.

b.	Anorexia.

c.	Weight loss.

d.	Gradual development of anaemia.

3.	Signs

a.	Pallor.

b.	Petechial haemorrhages.

c.	Splinter haemorrhages in nail beds.

d.	Splenomegaly.

e.	Finger clubbing.

f.	Roth spots on fundoscopy. 

4.	Investigations

a.	FBC.

b.	ESR.

c.	Blood cultures.

d.	ECHO.

5.	Causes:

a.	Streptococcus viridans.

b.	Staphylococci.

c.	Enterococci.

d.	E.coli.

e.	Candida albicans.

6.	Treatment

a.	Intravenous antibiotic therapy for 6 weeks.

b.	Prophylaxis against endocarditis in dental extractions and procedures, using amoxycillin started 1 – 2 hours prior to the procedure. 

Myocardial disease

1.	Cardiomyopathy

a.	A group of conditions with heart muscle disease and myocardial dysfunction, often associated with heart failure.

b.	Etiology is unknown and no specific treatment is available.

c.	Cardiac transplantation offers the only prospect of survival.

2.	Dilated cardiomyopathy

a.	Commonest form of cardiomyopathy.

b.	Symptoms: those of CCF, palpitations of syncope.

c.	Signs: hypotension, weak peripheral pulses and hepatomegaly.

d.	CXR shows dilatation of left ventricle and atrium. 

e.	Treatment involves use of anti-arrhythmics, beta-blockers, anticoagulants, a ventricular assist device or transplantation.

3.	Hypertrophic cardiomyopathy

a.	Inherited as autosomal dominant trait.

b.	Penetrance is incomplete in early childhood, increasing with age.

c.	Symptoms the same as for CCF.

d.	Signs: systolic murmur increased by exercise, standing, decreased by squatting, extra heart sounds, mid-diastolic rumble.

e.	CXR shows cardiomegaly, RVH and LVH.

f.	Surgery is an option for failed medical therapy to alleviate subaortic obstruction. 

Associated syndromes

1.	Marfan syndrome

a.	Autosomal dominant condition caused by defective fibrillin on chromosome 15.

b.	Major diagnostic criteria:

i.	dilatation of ascending aorta with or without regurgitation.

ii.	dissection of the ascending aorta.

c.	Minor diagnostic criteria:

i.	mitral valve prolapse with or without mitral valve regurgitation.

ii.	dilatation of main pulmonary artery.

iii.	dilatation or dissection of descending thoracic or abdominal aorta.

2.	Noonan syndrome

a.	Autosomal dominant condition associated with a gene locus at chromosome 12.

b.	Cardiac defects:

i.	dysplastic / stenotic pulmonary valve.

ii.	hypertrophic cardiomyopathy.

iii.	ASD.

iv.	VSD.

v.	tetralogy of Fallot.

c.	Symptomatic HCM in NS can lead to sudden cardiac death, even in infancy.

3.	Turner syndrome

a.	45 XO karyotype.

b.	Cardiac defects:

i.	coarctation of aorta.

ii.	bicuspid aortic valve.

iii.	aortic root dilatation.

c.	Prophylaxis for endocarditis is important as dental malocclusion occurs in Turner syndrome and may require dental procedures.