Clinical features of chronic and acute aortic regurgitation
THE CONTEXT
Aortic regurgitation may produce prominent heartbeat awareness and characteristic murmurs; acute severe disease can present predominantly with heart failure.
Symptoms
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Before breathlessness develops, the only symptom may be awareness of the heartbeat, particularly when lying on the left side, because of increased stroke volume.
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Paroxysmal nocturnal dyspnoea may be the first symptom. Peripheral oedema or angina may also occur.
Murmurs and the Austin Flint mechanism
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The characteristic diastolic murmur is best heard to the left of the sternum during held expiration and may extend to the apex. A thrill is rare.
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A systolic murmur caused by increased stroke volume is common and does not necessarily indicate stenosis.
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The regurgitant jet causes mitral valve fluttering. If severe, it partially closes the anterior mitral leaflet, producing functional mitral stenosis and a soft mid-diastolic Austin Flint murmur.
Acute severe aortic regurgitation
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Endocarditis can cause perforation or tearing of an aortic cusp, leading to acute severe regurgitation.
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There may be insufficient time for compensatory left ventricular hypertrophy and dilatation, so heart failure features may predominate.
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Tachycardia and an abrupt rise in left ventricular end-diastolic pressure may mask the classical signs. Pulse pressure may be normal or near normal, and the diastolic murmur may be short or absent.
Illustrated electrocardiographic findings
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The left ventricular hypertrophy tracing shows increased limb-lead QRS amplitude, very large R waves in V4 and V5, and a deep S wave in V3.
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ST depression and T-wave inversion in leads II, III, aVF, V5 and V6 are described as a left ventricular strain pattern.