Sensitivity and specificity of M mode echocardiographic signs of mitral valve prolapse.

To assess the sensitivity and specificity of previously described M mode echocardiographic signs of mitral valve prolapse, 100 subjects with a mobile mid systolic click and 100 matched normal control subjects were prospectively studied. Late systolic posterior motion and holosystolic hammocking of the mitral leaflets were common, highly specific signs of mitral valve prolapse. When these signs were combined as a single criterion, sensitivity was 85 percent and specificity was 99 percent. Other signs, including systolic echoes in the mid left atrium, systolic anterior motion, early diastolic anterior motion of the posterior mitral leaflet and shaggy or heavy cascading linear diastolic echoes posterior to the mitral valve, were highly specific but uncommon. They occurred only in combination with late systolic posterior motion or holosystolic hammocking. The remaining signs tested did not differentiate subjects with mitral valve prolapse from normal persons.