Ventricular septal defect: murmur and clinical presentation
THE CONTEXT
The clinical findings of a ventricular septal defect vary with defect size, right ventricular pressure and the haemodynamic effect of the shunt.
Murmur and haemodynamics
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Systolic flow from the high-pressure left ventricle to the low-pressure right ventricle produces a pansystolic murmur, usually loudest at the left sternal border and radiating across the precordium.
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A small defect often produces a loud murmur without other haemodynamic disturbance; this is termed maladie de Roger.
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A large defect produces a quieter murmur, particularly when right ventricular pressure is elevated.
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Elevated right ventricular pressure may occur immediately after birth while pulmonary vascular resistance remains high, or with shunt reversal in Eisenmenger syndrome.
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In some infants, the murmur becomes quieter or disappears because the defect closes spontaneously.
Presentation and cardiac failure
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Congenital ventricular septal defect may present with cardiac failure in infancy, a murmur with minor haemodynamic disturbance in older children or adults, or rarely Eisenmenger syndrome.
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A large left-to-right shunt can result in chamber enlargement.
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When cardiac failure complicates a large defect, it is usually absent immediately after birth and becomes apparent during the first 4–6 weeks of life.
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Associated findings include prominent parasternal pulsation, tachypnoea and indrawing of the lower ribs during inspiration.