Study note

Atrial septal defect: symptoms and auscultatory findings

THE CONTEXT

Atrial septal defect may remain asymptomatic for years. Its characteristic physical signs reflect right ventricular volume overload.

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Most children remain asymptomatic for many years, and the defect is often detected during routine examination or following a chest X-ray.

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Symptoms include dyspnoea, cardiac failure and arrhythmias, especially atrial fibrillation.

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The characteristic second heart sound has wide, fixed splitting.

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The split is wide because right ventricular ejection is delayed by increased stroke volume and right bundle branch block.

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The split is fixed because the septal defect equalises left and right atrial pressures throughout the respiratory cycle.

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A systolic flow murmur is heard over the pulmonary valve.

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Children with a large shunt may also have a low-pitched mid-diastolic flow murmur at the lower left sternal edge.

NEETx

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