Early Systolic Clicks due to Mitral Valve Prolapse

Four patients had evidence that mitral valve prolapse was the etiology of isolated early systolic clicks that were “ejection” in timing, that is, within 80 msec of the first heart sound (S1). Phonocardiography demonstrated movement of the click closer to S1 (three patients) with no change (three patients) or an increase in click amplitude (one patient) on inspiration. Earlier movement of systolic clicks on inspiration is a known feature of midsystolic clicks related to mitral valve prolapse but not of true aortic ejection sounds. In three patients the early systolic click showed a variable relation to the carotid upstroke, suggesting that the two events were not related. The click of the fourth patient occurred after the carotid upstroke. In one patient the click could be brought out by standing. Apical holosystolic murmurs could be elicited in all patients. Left- and right-heart catheterizations and left ventricular angiograms revealed no evidence of semilunar valve or great vessel root abnormality. Three patients had mitral valve prolapse and mitral regurgitation on left ventriculogram. The cineangiogram on one patient demonstrated maximal prolapse of the mitral valve just before opening of the aortic valve and coincident with the timing of the click. An isolated early systolic click may be due to mitral valve prolapse rather than to the usual ejection phenomena.