Diastolic sounds and murmurs associated with mitral valve prolapse.

Although mitral valve prolapse is often associated with a systolic click or murmur, it is not widely appreciated that a sound or murmur may also occur in diastole. Nine patients with a systolic click or murmur and echocardiographic evidence of mitral prolapse had, in addition, a diastolic sound or an early diastolic murmur best heard at the apex or left sternal border. The sound, which was of high frequency and easily audible, followed A2 by 70-110 msec (mean 94 +/- 5 msec), and coincided with the point where the prolapsed posterior leaflet returned from the left atrium and recoapted with the anterior mitral leaflet. The diastolic sound occurred 40-60 msec (mean 53 +/- 4 msec) before the E point of the echocardiogram and O point of the apexcardiogram, and even longer before the rapid-filling wave. The diastolic murmur, also of high frequency, was brief and decrescendo, and simulated aortic regurgitation in two patients. Thus, mitral prolapse may be associated with a sound or murmur in diastole. When a diastolic sound or murmur is best heard apically, even if accompanied by a systolic murmur, mitral valve prolapse should be considered.