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Atrial septal defect — RACP Paediatrics MCQ

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ModerateCardiologyAtrial septal defectRACP Paediatrics

A 5-year-old girl has a grade 2/6 ejection systolic murmur at the upper left sternal edge with a widely fixed split second heart sound. ECG shows right axis deviation and incomplete right bundle branch block. She is asymptomatic. What is the most likely diagnosis?

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Correct answer: E — Atrial septal defect (secundum)

A widely fixed split S2 is the hallmark finding of an ASD. The ejection systolic murmur at the upper left sternal edge is due to increased flow across the pulmonary valve. Right axis deviation and incomplete RBBB on ECG support the diagnosis of a secundum ASD.

Reference: RCH Melbourne – 2023 – Congenital Heart Disease CPG; RACP Paediatric Curriculum – Cardiology