Ventricular extrastimulation in the mitral valve prolapse syndrome. Evidence for ventricular reentry.

Fourteen patients with mitral valve prolapse and essentially normal coronary arteries were evaluated for ventricular arrhythmias, utilizing programmed ventricular extrastimulation. Three were symptomatic with ventricular tachyarrhythmias. Application of appropriately timed ventricular extrasystoles initiated the tachyarrhythmias in these three patients. The remaining eleven mitral prolapse patients were apparently free of tachycardias. Repetitive ectopic beats were not induced by extrastimulation in these eleven patients. The initiation of ventricular tachyarrhythmias by extrastimulation suggests a reentrant mechanism for the ventricular ectopy of mitral valve prolapse.