Common Congenital Heart Diseases in Pediatrics

Definition

Classification

Frequency (Robbins Basic Pathology, Table 9.1)

1. Ventricular Septal Defect (VSD) - Most Common CHD

• Perimembranous (most common, ~80%)
• Muscular
• Inlet (endocardial cushion type)
• Outlet (supracristal)

• Small VSD: Loud pansystolic murmur at lower left sternal border (Maladie de Roger) - often asymptomatic
• Large VSD: Dyspnea, feeding difficulty, failure to thrive, recurrent chest infections, cardiac failure
• Signs: Tachycardia, cardiomegaly, palpable left parasternal thrill, mid-diastolic mitral flow murmur

• CXR: Cardiomegaly, increased pulmonary vascular markings
• ECG: Biventricular hypertrophy
• Echocardiography: Confirmatory (shows defect size and direction of shunt)

• Small VSD: 30-40% close spontaneously; no intervention needed
• Large VSD: Surgical closure (patch repair) or catheter-based device closure before 6 months to prevent pulmonary hypertension

2. Atrial Septal Defect (ASD)

• Ostium secundum (most common, ~70%) - at fossa ovalis
• Ostium primum - lower atrial septum (associated with Down syndrome)
• Sinus venosus - near SVC or IVC junction

• Often asymptomatic in childhood
• Mild exercise intolerance, recurrent respiratory infections
• Signs: Fixed, widely split S2 (hallmark); ejection systolic murmur in pulmonary area (from increased flow across pulmonary valve); mid-diastolic murmur at tricuspid area (from increased tricuspid flow)

• CXR: Right atrial and ventricular enlargement, prominent pulmonary artery, increased pulmonary vascular markings
• ECG: Right axis deviation, right bundle branch block (rSR' pattern in V1), right ventricular hypertrophy
• Echo: Confirmatory

• Device (Amplatzer occluder) or surgical closure by age 3-5 years before pulmonary hypertension develops

3. Patent Ductus Arteriosus (PDA)

• Asymptomatic with small PDA
• Tachypnea, poor feeding, recurrent chest infections, heart failure with large PDA
• Characteristic continuous "machinery" murmur (Gibson's murmur) at left infraclavicular region, best heard in systole and diastole
• Bounding peripheral pulses, wide pulse pressure

• CXR: Left ventricular enlargement, dilated ascending aorta, increased pulmonary markings
• ECG: Left ventricular hypertrophy
• Echo + Doppler: Demonstrates flow across ductus

• Preterm infants: Indomethacin (IV, COX inhibitor to promote prostaglandin-mediated closure) or Ibuprofen; Paracetamol (3rd line)
• Term infants / children: Catheter-based coil/device occlusion or surgical ligation

4. Tetralogy of Fallot (TOF) - Most Common Cyanotic CHD

• Cyanosis (usually appears at 3-6 months)
• Tet spells (hypercyanotic episodes): Paroxysmal, intense cyanosis during crying, feeding, or exertion due to acute drop in pulmonary flow
• Squatting posture (older children): Squatting increases systemic vascular resistance, reduces right-to-left shunt, and increases pulmonary flow
• Clubbing of fingers and toes (after 6 months)
• Failure to thrive

• Single S2 (soft/absent P2)
• Ejection systolic murmur at left upper sternal border (from pulmonary stenosis - paradox: softer murmur = more severe stenosis)
• No murmur from VSD (equalized pressures)

• CXR: Boot-shaped heart (coeur en sabot) - due to RV hypertrophy elevating cardiac apex and concave pulmonary artery segment; decreased pulmonary vascular markings; right aortic arch in 25%
• ECG: Right axis deviation, right ventricular hypertrophy
• Echo: Diagnostic - shows all four components
• CBC: Polycythemia (compensatory)

1. Knee-chest position (or squatting)
2. 100% oxygen
3. IV morphine (reduces infundibular spasm, calms patient)
4. IV fluids (volume expansion)
5. IV propranolol (reduces infundibular spasm)
6. IV sodium bicarbonate (for metabolic acidosis)

Eisenmenger Syndrome

• Key message: Early correction of shunts prevents Eisenmenger syndrome.

Summary Table

Note: O.P. Ghai Essential Pediatrics is the primary Indian MBBS reference for this topic. The frequency data and pathological descriptions above are consistent with Robbins & Kumar Basic Pathology (10th ed., Table 9.1, pp. 347-351), which aligns with Ghai's classification.

Management of Large VSD

Definition of Large VSD

A. Medical Management (Initial Stabilization)

1. Anti-failure treatment:
   • Diuretics - Furosemide (1-2 mg/kg/day) to reduce pulmonary congestion
   • Digoxin - improves cardiac contractility
   • ACE inhibitors (Captopril) - reduce afterload, decrease left-to-right shunt
2. Nutritional support:
   • High-calorie feeds (150-180 kcal/kg/day) - nasogastric feeds if needed
   • Treat failure to thrive
3. Treat infections: Prompt treatment of recurrent chest infections

B. Surgical/Interventional Management (Definitive)

C. Indications for Surgery

• Large VSD with cardiac failure not controlled by medical therapy
• Failure to thrive despite optimal medical management
• Qp:Qs > 2:1 (pulmonary to systemic flow ratio)
• Rising pulmonary artery pressure

D. Contraindication

• Eisenmenger syndrome (irreversible pulmonary hypertension with reversed shunt) - surgery contraindicated as it would fatally overload the RV.

Key Point to Remember

"Operate before pulmonary hypertension becomes irreversible" - Large VSDs must be closed within the first 6 months of life. Spontaneous closure does NOT occur in large VSDs (only in small/moderate defects).

Acute Rheumatic Fever (ARF)

1. Definition

2. Etiology

• Causative organism: Group A beta-hemolytic Streptococcus pyogenes (mucoid rheumatogenic strains - types 3, 5, 18)
• Preceding infection: Streptococcal pharyngitis (NOT skin infection / impetigo)
• Latent period: Symptoms appear 2-6 weeks after pharyngitis (chorea appears later at 4-8 weeks)
• Age group: Most common between 5-15 years; rare before age 3
• Risk factors: Overcrowding, poverty, malnutrition, low socioeconomic status

3. Pathophysiology

GAS Pharyngitis
        ↓
Streptococcal M-protein antigens (molecular mimicry)
        ↓
Host produces antibodies against streptococcal antigens
        ↓
Cross-reaction with host tissues:
  • Cardiac myosin → Carditis (Aschoff bodies)
  • Synovium → Migratory arthritis
  • Basal ganglia → Chorea (Sydenham's)
  • Skin → Erythema marginatum, subcutaneous nodules
        ↓
Immune complex deposition + CD4+ T-cell mediated injury
        ↓
Pancarditis (pericardium + myocardium + endocardium)
        ↓
Repeated attacks → Fibrosis → Rheumatic Heart Disease

4. Jones Criteria (Revised, 2015 AHA)

Major Criteria (CANES)

Minor Criteria

Evidence of Preceding GAS Infection (mandatory)

• Positive throat culture or rapid antigen test
• Elevated or rising ASO (Antistreptolysin O) titre >200 Todd units in children
• Elevated anti-DNase B titre
• History of scarlet fever

5. Investigations

To Confirm GAS Infection

Acute Phase Reactants

Cardiac Investigations

6. Management

A. Bed Rest

• Strict bed rest during acute phase
• Duration depends on presence of carditis:
  • No carditis: 2-4 weeks
  • Carditis without cardiomegaly: 4-6 weeks
  • Carditis with cardiomegaly: 3-6 months

B. Eradication of GAS (Anti-streptococcal Therapy)

C. Anti-inflammatory Therapy

D. Treatment of Heart Failure

• Digoxin, diuretics (Furosemide), ACE inhibitors
• Oxygen if needed

E. Treatment of Chorea

• Bed rest in quiet environment
• Haloperidol or Carbamazepine or Valproic acid
• Anti-inflammatory drugs not very effective for chorea

7. Secondary Prophylaxis (Prevention of Recurrence)

Duration of Prophylaxis (O.P. Ghai guidelines)

8. Complications

• Rheumatic Heart Disease - most important; mitral stenosis (most common chronic lesion from repeated attacks)
• Infective endocarditis
• Atrial fibrillation (from mitral stenosis)
• Heart failure

Key Memory Aids

Jones Criteria Major = CANES (Carditis, Arthritis, Nodules, Erythema marginatum, Sydenham's chorea)

"Throat hurts once - heart hurts forever" - emphasizes why secondary prophylaxis is mandatory

Arthritis is the most common manifestation; Carditis is the most serious manifestation; Chorea is the most specific (pathognomonic) manifestation.

What Was Already Covered (Scroll Up)

1. Etiology - Group A beta-hemolytic Streptococcus pyogenes, rheumatogenic strains (types 3, 5, 18), preceded by pharyngitis, latent period 2-6 weeks
2. Pathophysiology - Molecular mimicry → cross-reactive antibodies → pancarditis (Aschoff bodies), migratory arthritis, Sydenham's chorea, skin lesions
3. Jones Criteria (Revised 2015)
   • Major (CANES): Carditis, Arthritis, Nodules, Erythema marginatum, Sydenham's chorea
   • Minor: Fever, Arthralgia, Elevated ESR/CRP, Prolonged PR interval
   • Diagnosis = 2 Major OR 1 Major + 2 Minor + evidence of GAS
4. Investigations - Throat culture, ASO titre, Anti-DNase B, ESR, CRP, CBC, ECG, CXR, Echocardiography
5. Management
   • Bed rest
   • Benzathine Penicillin G (eradication)
   • Aspirin (arthritis/mild carditis) vs Prednisolone (severe carditis)
   • Haloperidol/Carbamazepine (chorea)
   • Secondary prophylaxis (3-weekly Benzathine Penicillin - lifelong if valve disease)

Acute Rheumatic Fever (ARF)

1. ETIOLOGY

• Organism: Group A beta-hemolytic Streptococcus pyogenes (rheumatogenic strains - M types 1, 3, 5, 18)
• Preceding infection: Streptococcal pharyngitis only (NOT skin/impetigo)
• Latent period: 2-6 weeks after pharyngitis
• Age: 5-15 years most common
• Risk factors: Overcrowding, poverty, low socioeconomic status

2. PATHOPHYSIOLOGY

GAS Pharyngitis (throat infection)
           ↓
Streptococcal M-protein → antibody formation
           ↓
MOLECULAR MIMICRY
(antibodies cross-react with host tissues)
           ↓
Heart muscle (myosin) → CARDITIS (Aschoff bodies)
Synovium                → MIGRATORY ARTHRITIS
Basal ganglia           → CHOREA (Sydenham's)
Skin                    → Erythema marginatum
Subcutaneous tissue     → Nodules
           ↓
Repeated attacks → Fibrosis → RHEUMATIC HEART DISEASE

• Aschoff body = Pathognomonic lesion - perivascular granuloma with fibrinoid necrosis + Anitschkow (caterpillar) cells
• Mitral valve most commonly affected → Mitral regurgitation (acute) → Mitral stenosis (chronic)

3. JONES CRITERIA (Revised 2015 AHA)

Diagnosis = 2 Major OR 1 Major + 2 Minor + Evidence of preceding GAS infection

Major Criteria - "CANES"

Minor Criteria

Evidence of Preceding GAS Infection (Mandatory)

• Positive throat culture / rapid antigen test
• Elevated ASO titre (>200 Todd units in children)
• Elevated Anti-DNase B titre
• History of scarlet fever

4. INVESTIGATIONS

A. To Confirm GAS Infection

B. Acute Phase Reactants

C. Cardiac Workup

5. MANAGEMENT

A. Bed Rest

B. Eradication of GAS (Anti-streptococcal Therapy)

C. Anti-inflammatory Therapy

D. Chorea Treatment

• Haloperidol / Carbamazepine / Valproic acid
• Quiet environment, reduced stimulation

E. Heart Failure

• Digoxin + Furosemide + ACE inhibitors + Oxygen

F. Secondary Prophylaxis (MOST IMPORTANT)

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