Overview/Definition
Definition:
• Ventricular septal defect (VSD) is the most common congenital heart defect, accounting for 25-30% of all CHD cases
Represents abnormal communication between right and left ventricles through interventricular septum defect
Critical condition requiring age-specific management approach for optimal outcomes.
Epidemiology:
• Incidence of 1.5-3.5 per 1000 live births in India with higher prevalence in low birth weight infants
Male to female ratio approximately 1:1.2
Associated with maternal diabetes, phenylketonuria, and chromosomal abnormalities including Down syndrome (40% incidence).
Age Distribution:
• Perimembranous VSDs (80-85% of cases) typically present in infancy
Muscular VSDs (10-15%) often diagnosed in neonatal period
Outlet VSDs (5%) associated with aortic regurgitation
Spontaneous closure rates: small VSDs 90%, moderate VSDs 50%, large VSDs <10%.
Clinical Significance:
• High-yield topic for DNB Pediatrics and NEET SS examinations focusing on Eisenmenger syndrome prevention, timing of surgical intervention, and complications
Essential for understanding shunt physiology, heart failure development, and long-term prognosis in pediatric cardiology practice.
Age-Specific Considerations
Newborn:
• Neonatal presentation often asymptomatic due to elevated pulmonary vascular resistance
Small VSDs may not produce murmurs until PVR drops at 4-6 weeks
Large VSDs can present with congestive heart failure by 6-8 weeks as PVR decreases and left-to-right shunt increases.
Infant:
• Critical period for CHF development (6 weeks-6 months) as pulmonary vascular resistance falls
Growth failure, feeding difficulties, tachypnea, and diaphoresis common in moderate-large VSDs
Increased susceptibility to respiratory tract infections
Peak age for spontaneous closure (6 months-2 years).
Child:
• Asymptomatic small VSDs with normal growth and development
Moderate VSDs may show exercise intolerance, fatigue, and recurrent respiratory infections
Large unrepaired VSDs risk developing pulmonary hypertension and Eisenmenger syndrome by school age (5-8 years).
Adolescent:
• Previously undiagnosed small VSDs may present with endocarditis risk
Large unrepaired VSDs develop irreversible pulmonary hypertension with cyanosis and clubbing
Exercise restriction necessary for moderate-large VSDs
Genetic counseling important for future pregnancy planning.
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Clinical Presentation
Symptoms:
• Small VSDs: Usually asymptomatic with normal growth and activity tolerance
Moderate VSDs: Feeding difficulties, poor weight gain, exercise intolerance, recurrent respiratory infections
Large VSDs: Congestive heart failure symptoms including tachypnea, diaphoresis during feeds, failure to thrive, and irritability.
Physical Signs:
• Harsh holosystolic murmur grade 3-6/6 heard best at left lower sternal border radiating to right sternal border
Small VSDs produce louder murmurs than large VSDs (Roget sign)
Large VSDs: displaced PMI, thrill, wide pulse pressure, early diastolic murmur of pulmonary regurgitation.
Severity Assessment:
• Small VSDs: Normal chest X-ray and ECG, murmur <3/6, no symptoms
Moderate VSDs: Cardiomegaly on chest X-ray, left atrial enlargement, mild symptoms
Large VSDs: Significant cardiomegaly, pulmonary plethora, biventricular hypertrophy on ECG, CHF symptoms requiring medical management.
Differential Diagnosis:
• Differential includes mitral regurgitation, tricuspid regurgitation, pulmonary stenosis, and AVSD
Patent ductus arteriosus presents with continuous machinery murmur
Tetralogy of Fallot shows right ventricular outflow obstruction with cyanosis
Aortic stenosis produces systolic ejection murmur at right sternal border.
Diagnostic Approach
History Taking:
• Detailed prenatal history including maternal diabetes, medications, infections
Birth history including prematurity and birth weight
Feeding pattern assessment including duration, volume, and associated symptoms
Developmental milestone achievement and growth pattern evaluation
Family history of congenital heart disease.
Investigations:
• Chest X-ray shows cardiomegaly and increased pulmonary vascular markings in moderate-large VSDs
ECG may show left atrial enlargement, LVH, or biventricular hypertrophy
Echocardiography is diagnostic showing defect location, size (small <3mm, moderate 3-6mm, large >6mm), and hemodynamic assessment.
Normal Values:
• Normal chest X-ray: Cardiothoracic ratio <0.55 in infants, <0.50 in children
Normal ECG: QRS axis 60-180° in infants, 0-120° in children
Normal LVEF >55%, normal RV systolic pressure <30mmHg in children
Qp/Qs ratio: normal <1.5, significant shunt >2.0.
Interpretation:
• Restrictive VSDs show high velocity flow (>4 m/s) with minimal shunting
Non-restrictive VSDs demonstrate low velocity flow (<2.5 m/s) with significant left-to-right shunt
Pulmonary artery pressure assessment crucial: PAP >50mmHg or Rp/Rs >0.5 suggests increased surgical risk and potential contraindication.
Management/Treatment
Acute Management:
• Congestive heart failure management: diuretics (furosemide 1-2mg/kg/dose), ACE inhibitors (captopril 0.1-0.5mg/kg TID), digoxin (10-15mcg/kg loading, 5-10mcg/kg maintenance)
High calorie feeding (150-180 kcal/kg/day) to promote growth
Treat respiratory infections promptly with antibiotics.
Chronic Management:
• Small VSDs: Regular follow-up every 1-2 years with clinical assessment and echocardiography
Endocarditis prophylaxis only for first 6 months post-repair
Moderate VSDs: Consider surgery if CHF symptoms, growth failure, or significant left heart volume overload (LA/Ao ratio >1.5).
Lifestyle Modifications:
• Age-appropriate activity restrictions: small VSDs allow normal activity, moderate-large VSDs restrict competitive sports
Nutritional support with high-calorie formula or nasogastric feeds if growth failure
Immunizations including influenza and RSV prophylaxis (palivizumab) in high-risk infants
Dental hygiene maintenance.
Follow Up:
• Surgical timing: Optimal age 3-6 months for symptomatic large VSDs, before 2 years if pulmonary hypertension develops
Contraindications include Eisenmenger syndrome (Rp/Rs >0.7, bidirectional shunt)
Post-operative follow-up annually with echocardiography to assess for residual shunt, arrhythmias, and ventricular function.
Age-Specific Dosing
Medications:
• Furosemide: Neonates 1mg/kg BID, Infants 1-2mg/kg BID, Children 1mg/kg BID (max 40mg/dose)
Captopril: Neonates 0.01-0.05mg/kg TID, Infants 0.1-0.5mg/kg TID, Children 0.3-2mg/kg TID (max 25mg TID)
Digoxin loading: Full-term 10-15mcg/kg, Premature 5-10mcg/kg.
Formulations:
• Oral furosemide available as 10mg/5mL syrup, tablets scored for pediatric dosing
Captopril available as 25mg tablets (crush and suspend for infants)
Digoxin pediatric elixir 50mcg/mL preferred over tablets in children <10kg
Spironolactone 25mg tablets can be compounded into suspension.
Safety Considerations:
• Monitor electrolytes (Na+, K+, Mg2+) weekly initially, then monthly during diuretic therapy
Watch for digoxin toxicity signs: vomiting, arrhythmias, AV blocks
ACE inhibitor monitoring: renal function, hyperkalemia risk
Avoid NSAIDs which can worsen heart failure and reduce diuretic effectiveness.
Monitoring:
• Growth parameters monthly in infants, every 3 months in children
Echocardiography every 3-6 months in symptomatic patients, annually in asymptomatic small VSDs
ECG monitoring for arrhythmias and conduction blocks
BNP levels can guide heart failure management (normal <100 pg/mL in children).
Prevention & Follow-up
Prevention Strategies:
• Primary prevention limited as most VSDs are sporadic congenital anomalies
Folic acid supplementation (400mcg daily) during pregnancy may reduce overall CHD risk
Maternal diabetes control important as hyperglycemia increases VSD risk
Avoid teratogenic medications during first trimester including phenytoin and warfarin.
Vaccination Considerations:
• Standard immunization schedule with additional influenza vaccine annually
RSV prophylaxis (palivizumab 15mg/kg IM monthly during RSV season) for infants <2 years with hemodynamically significant VSDs
COVID-19 vaccination recommended for children >6 months with congenital heart disease as high-risk group.
Follow Up Schedule:
• Neonates with large VSDs: weekly until stable, then monthly
Infants: every 3 months for symptomatic, every 6 months for asymptomatic
Children with small VSDs: annually until spontaneous closure or school age
Post-surgical patients: 1 week, 1 month, 3 months, then annually lifelong.
Monitoring Parameters:
• Growth velocity using WHO growth charts with plot trajectory
Exercise tolerance assessment using age-appropriate functional class
Echocardiographic parameters: VSD size, shunt direction, PA pressure, ventricular function
ECG for rhythm abnormalities and conduction delays
Oxygen saturation monitoring for Eisenmenger development.
Complications
Acute Complications:
• Congestive heart failure most common in infants with moderate-large VSDs, presenting with failure to thrive, tachypnea, hepatomegaly
Infective endocarditis risk 3-4 times higher than general population
Respiratory tract infections more frequent and severe due to increased pulmonary blood flow and CHF.
Chronic Complications:
• Eisenmenger syndrome development (irreversible pulmonary hypertension with shunt reversal) typically by age 10-20 years in unrepaired large VSDs
Aortic regurgitation particularly with outlet VSDs (5-7% develop AR)
Left ventricular outflow tract obstruction can develop due to septal hypertrophy or accessory mitral valve tissue.
Warning Signs:
• Cyanosis development suggests either Eisenmenger syndrome or associated pulmonary stenosis
Decreased exercise tolerance, syncope, or chest pain indicate possible pulmonary hypertension
Growth failure, feeding difficulties, or increased work of breathing suggest worsening CHF requiring urgent evaluation.
Emergency Referral:
• Immediate cardiology referral for: new onset cyanosis, signs of CHF (tachypnea >60/min in infants), failure to thrive crossing growth percentiles, suspected endocarditis (fever with new murmur)
Emergency surgery indicated for CHF refractory to medical management or life-threatening arrhythmias.
Parent Education Points
Counseling Points:
• Explain VSD as "hole in heart wall between pumping chambers" allowing blood mixing
Emphasize that small VSDs often close spontaneously by age 2-4 years (80-90% closure rate)
Discuss normal life expectancy with appropriate management and surgery when indicated
Address genetic counseling for future pregnancies (2-3% recurrence risk).
Home Care:
• Monitor daily weights in CHF patients (>30g/day gain in infants warrants medical attention)
Recognize feeding cues and provide frequent small feeds with high-calorie formula (24-27 kcal/oz)
Position infant upright during feeds to reduce work of breathing
Maintain good dental hygiene to prevent endocarditis risk.
Medication Administration:
• Give medications at consistent times with food to minimize GI upset
Measure liquid medications precisely using provided syringes or measuring spoons
Store digoxin safely away from children as small overdoses can be fatal
Never skip doses without consulting cardiologist, especially digoxin and heart failure medications.
When To Seek Help:
• Seek immediate medical attention for: fast breathing (>60/min in infants), difficulty feeding lasting >30 minutes, poor weight gain or weight loss, fever >38°C, new onset fatigue or exercise intolerance
Call cardiologist for: missed medication doses >24 hours, vomiting preventing medication intake, or any concerning symptoms.