On the frequency of early systolic clicks in mitral valve prolapse.

Phonocardiography was performed in 74 patients with mitral valve prolapse. 24 patients had early systolic clicks (less than 80 msec from S1). Four of them had associated systolic murmurs. 30 patients had mid or late systolic clicks (greater than 80 msec from S1). A systolic murmur followed the click in 13 of these patients. Both an early and mid/late systolic click were noted in three patients. 17 patients did not have systolic murmurs. Seven patients had 'silent' mitral valve prolapse. In summary, early systolic clicks are common in mitral valve prolapse. In many instances the early click is not accompanied by a murmur. Echocardiography is recommended in patients with chest pain or arrhythmia of uncertain etiology, even if characteristic signs of mitral valve prolapse are absent.