Study note

Persistent ductus arteriosus: clinical findings and shunt reversal

THE CONTEXT

Clinical manifestations vary with shunt size and may change when pulmonary vascular resistance increases.

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Small shunts may remain asymptomatic for years. A large ductus may retard growth and development.

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There is usually no disability in infancy, but cardiac failure may eventually develop, with dyspnoea as its first symptom.

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A continuous machinery murmur has late systolic accentuation and is maximal in the second left intercostal space below the clavicle.

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The murmur is often accompanied by a thrill, and pulses have increased volume.

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Radiology may reveal pulmonary artery enlargement. The electrocardiogram is usually normal.

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Increasing pulmonary vascular resistance may raise pulmonary artery pressure until it equals or exceeds aortic pressure.

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The shunt may then reverse, causing Eisenmenger syndrome. The murmur becomes quieter and may be confined to systole or disappear.

NEETx

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