Conduction disturbances in patients with mitral valve prolapse.

The electrocardiograms (ECGs) of 55 patients with mitral valve prolapse were analyzed. Twelve of these demonstrated conduction abnormalities. Five patients had first degree heart block. Three had the classic ECG changes of the Wolff-Parkinson-White syndrome. Two patients had left anterior hemiblock, one of whom also had incomplete right bundle branch block. One patient had episodes of advanced atrioventricular block and periods of sinus arrest, which resulted in recurrent syncopal attacks. One patient had incomplete left bundle branch block. The presence of conduction disturbances points to the diffuse nature of the myocardial abnormality in mitral valve prolapse.