Makindo Medical Notes

Related Subjects: |Congenital Acyanotic Heart Disease |Congenital Cyanotic Heart Disease |Cardiac Embryology |Cyanosis - Central and Peripheral |Down's syndrome (Trisomy 21) |Tetralogy of Fallot |Patent Foramen Ovale (PFO) |Ventricular Septal defect (VSD)

🫀 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