🫀 Ventricular Septal Defect (VSD) is the most common congenital heart defect (≈2/1000 live births). Small VSDs often 🎶 produce loud murmurs but are well tolerated, while large VSDs may be quieter but cause heart failure by 6–8 weeks. Many small muscular defects close spontaneously.

📌 About

Abnormal shunt between LV → RV.
Classic finding: harsh pansystolic murmur ± thrill at lower left sternal edge.
Symptomatic infants: poor weight gain, tachypnoea, feeding fatigue.

🧬 Aetiology & Pathophysiology

Size of defect + pulmonary pressures dictate severity.
Large, uncorrected defects → pulmonary hypertension → reversal of shunt = Eisenmenger’s syndrome (cyanosis, clubbing, ↓ murmur).
High risk of endocarditis – vigilance required.

🔎 Anatomical Types

Perimembranous – most common; near valves; may close spontaneously; risk aortic regurgitation.
Muscular – “Swiss cheese”; high chance of closure.
Inlet (AV canal) – linked with Down syndrome; often surgical.
Outlet (subarterial) – more frequent in Asia; risk aortic cusp prolapse → early surgery.
Gerbode – rare LV→RA defect.

🩺 Clinical Features

🎶 Loud pansystolic murmur ± thrill (small VSD louder than large).
Hyperdynamic apex beat, pulmonary overcirculation signs.
Failure to thrive, recurrent chest infections.
Eisenmenger’s: RV lift, cyanosis, murmur softens/disappears.

🧪 Investigations

Bloods: FBC (anaemia), CRP/ESR if ?endocarditis.
CXR: Normal in small; cardiomegaly & pulmonary plethora in large.
ECG: Normal if small; LVH + RVH if large.
Echocardiography: 🥇 gold standard – defect site, shunt size, PA pressure.

💊 Management

Observation 👀: Most small VSDs close spontaneously → regular follow-up.
Medical: Diuretics, ACE inhibitors, digoxin for symptomatic infants awaiting repair.
Surgical Repair 🩻: Patch closure for large, symptomatic, or failing to thrive defects (often in early childhood).
Device Closure: Via catheter – mainly muscular VSDs.
Endocarditis Prophylaxis: NICE: only if previous endocarditis or prosthetic material used. But clinicians must remain alert 🚨.
Long-term follow-up: Monitor for arrhythmias, residual defects, pulmonary hypertension.

⚠️ Complications

Infective endocarditis
Heart failure & pulmonary hypertension
Arrhythmias (esp. post-surgery)
Eisenmenger’s syndrome

🔍 Comparison: ASD vs VSD vs PDA

Feature	ASD	VSD	PDA
Definition	Abnormal communication between atria (usually secundum type).	Shunt between LV → RV (most common congenital defect).	Persistent communication between aorta & pulmonary artery.
Murmur	🌬️ Fixed split S2 + ejection systolic murmur (↑ flow across pulmonary valve).	🎶 Harsh pansystolic murmur ± thrill at LLSB (small = louder).	🔄 Continuous “machinery” murmur below left clavicle.
Clinical Features	Often asymptomatic in childhood; recurrent chest infections; exercise intolerance in adults.	Failure to thrive, HF by 6–8 weeks if large; recurrent chest infections; FTT.	Bounding pulses, wide pulse pressure, HF in infancy if large.
ECG	RAD, RBBB pattern (esp. secundum ASD).	LVH ± RVH in large defects; normal if small.	LVH ± RVH in large ducts.
CXR	Cardiomegaly, prominent pulmonary arteries.	Small: normal; Large: cardiomegaly, pulmonary plethora.	Cardiomegaly, ↑ pulmonary markings.
Complications	Paradoxical emboli, pulmonary hypertension, arrhythmias (AF).	Endocarditis, Eisenmenger’s, arrhythmias, HF.	Endocarditis, Eisenmenger’s (late), HF.
Management	Device/surgical closure if large shunt or symptomatic.	Observe if small; surgery/device closure if symptomatic/large.	Indomethacin/ibuprofen (in neonates) or surgical/device closure if persistent.

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Ventricular Septal defect (VSD) 💔