✅ Model Answer:
• Diagnosis: Congestive heart failure secondary to congenital heart disease (large VSD) – poor feeding, sweating during feeds, tachypnea, lower extremity edema, cardiomegaly, pulmonary edema, elevated BNP (500 pg/mL), dilated left ventricle with EF 30%.
• Any other test: ECG (LVH, RVH), baseline renal function, Echocardiogram, liver function, blood culture (rule out sepsis), genetic testing if syndromic (22q11 deletion), pulse oximetry.
• What to do next: Start diuretics (furosemide 1-2 mg/kg/dose), afterload reduction (ACE inhibitor – enalapril 0.1 mg/kg/dose), digoxin if systolic dysfunction. Consult pediatric cardiology for VSD closure planning. Optimize feeding (calorie-dense formula, NG feeds if needed).
• Follow-up plan: Monitor weight, urine output, respiratory status, oxygen saturation. Repeat echocardiogram. Surgical repair of VSD when stable/age-appropriate (usually 3-6 months). Long-term cardiac follow-up.

✅ Model Answer:
• Feeding difficulties: Poor feeding, fatigue during feeds, excessive sweating (especially during feeds)
• Respiratory: Tachypnea, dyspnea, retractions, grunting, cyanosis
• Cardiovascular: Tachycardia, gallop rhythm (S3), hepatomegaly, cardiomegaly
• Edema: Periorbital, pedal, sacral, generalized (in severe cases)
• Other: Poor weight gain, failure to thrive, lethargy, irritability
• Infants may present with: Feeding difficulty + sweating + tachypnea (classic triad)

✅ Model Answer:
• Congenital heart disease (most common):
- Left-to-right shunts: VSD, ASD, PDA (most common cause in infants)
- Obstructive lesions: Coarctation of aorta, critical aortic stenosis, hypoplastic left heart syndrome
- Cyanotic lesions: Tetralogy of Fallot, transposition of great arteries
• Non-cardiac causes:
- Myocarditis (viral, post-infectious)
- Cardiomyopathy (dilated, hypertrophic)
- Arrhythmias (tachyarrhythmias, bradyarrhythmias)
- Sepsis
- Anemia
- Renal failure
- Metabolic disorders

✅ Model Answer:
• BNP (Brain Natriuretic Peptide):
- Released from cardiac ventricles in response to increased wall stress and volume overload
- Elevated BNP indicates heart failure
- Normal values: <100 pg/mL (children)
- Mild HF: 100-300 pg/mL
- Moderate HF: 300-1000 pg/mL
- Severe HF: >1000 pg/mL
• Useful for:
- Diagnosis of heart failure
- Monitoring treatment response
- Prognostic marker
- Distinguishing cardiac from respiratory causes of distress
• Limitations: May be elevated in renal failure, sepsis, or pulmonary hypertension

✅ Model Answer:
• Diuretics: Furosemide 1-2 mg/kg/dose IV/PO (reduce fluid overload, pulmonary edema)
• Afterload reduction: ACE inhibitors (Enalapril 0.1 mg/kg/dose, titrate up) – reduce systemic vascular resistance, improve forward flow
• Inotropic support: Digoxin (for systolic dysfunction) – 10-15 µg/kg loading, maintenance 5-10 µg/kg/day
• Oxygen therapy: If hypoxemic
• Nutritional support: Calorie-dense formula (24-30 kcal/oz), NG feeding if poor intake
• Fluid restriction: If severe edema or hyponatremia
• Treat underlying cause: VSD closure, PDA ligation, correction of arrhythmia

✅ Model Answer:
• Echocardiographic findings:
- VSD: Defect in interventricular septum, color Doppler shows left-to-right shunt
- Left ventricular dilation: Due to volume overload
- Reduced ejection fraction (EF): <50% indicates systolic dysfunction
- Pulmonary hypertension: Elevated pulmonary artery pressure (estimated by tricuspid regurgitation velocity)
- Left atrial enlargement: Due to increased pulmonary venous return
- Right ventricular hypertrophy: Due to pulmonary hypertension
- VSD size: Large VSD (≥50% of aortic root diameter) is hemodynamically significant

✅ Model Answer:
• Complications:
- Failure to thrive: Poor weight gain, malnutrition
- Pulmonary edema: Respiratory distress, need for ventilation
- Pulmonary hypertension: Increased pulmonary vascular resistance → Eisenmenger syndrome (reversal of shunt)
- Cardiac arrhythmias: Atrial or ventricular arrhythmias
- Thromboembolism: Due to stasis and hypercoagulability
- Endocarditis: Risk with CHD, especially VSD
- Hepatomegaly and ascites: Due to right-sided failure
- Death: If untreated, especially in severe cases
- Long-term: Chronic HF → cardiomyopathy → need for heart transplant

✅ Model Answer:
• Surgical management:
- VSD closure: Usually performed at 3-6 months of age
- Indications: Failure to thrive, refractory heart failure, pulmonary hypertension
- Types: Patch closure (surgical) or device closure (transcatheter, if suitable)
- Pre-operative: Medical optimization (diuretics, ACE inhibitors, nutrition)
• Prognosis:
- Excellent with timely surgical repair
- Mortality: <2% for isolated VSD repair in experienced centers
- Long-term: Normal growth, normal activity, no residual shunt
- Follow-up: Regular cardiology follow-up for arrhythmias, endocarditis prophylaxis (if device), pulmonary hypertension monitoring
- If untreated: Progressive pulmonary hypertension → Eisenmenger syndrome (poor prognosis)