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Ventricular septal defect — RACP Paediatrics MCQ

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HardCardiologyVentricular septal defectRACP Paediatrics

A 7-week-old has poor feeding, sweating with feeds and tachypnoea. Examination reveals hepatomegaly and a harsh pansystolic murmur at the left lower sternal edge; oxygen saturation is 97%. What is the most likely cause?

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Correct answer: A — Falling pulmonary vascular resistance increasing left-to-right shunt

A large ventricular septal defect often becomes symptomatic at 4 to 8 weeks as pulmonary vascular resistance falls, increasing pulmonary blood flow and heart failure symptoms. Ductal closure typically causes deterioration in duct-dependent lesions rather than this saturated left-to-right shunt picture. The pearl is that timing of symptoms after birth can reveal the physiology of congenital heart lesions.

Reference: RCH Clinical Practice Guidelines; Paediatric cardiology texts; Therapeutic Guidelines (eTG)