MITRAL-VALVE PROLAPSE AND VENTRICULAR ARRHYTHMIAS - OBSERVATIONS IN APATIENT WITH A 20-YEAR HISTORY

Ventricular Arrhythmias in MVP. Introduction: Ventricular arrhythmias are a common feature in patients with mitral valve prolapse, In an att empt to determine the origin and underlying electrophysiologic mechani sm, we describe a patient with ventricular fibrillation, exercise-indu ced ventricular tachycardia (VT), and, at the time of diagnosis, prola pse of the posterior mitral valve leaflet without mitral regurgitation . Methods and Results: Treatment with beta-blockade and diphenylhydant oin prevented the occurrence of malignant ventricular arrhythmias for more than 17 years, Discontinuation of the therapy resulted in an imme diate reappearance of the VT, which, despite the marked enlargement of the left ventricle (secondary to development of severe mitral valve r egurgitation), had a strikingly similar morphology, For hemodynamic re asons, the patient was finally selected for valve replacement, Detaile d pre-, peri-, and postoperative studies were performed, including adm inistration of flunarizine, body surface mapping, construction of peri operative epicardial and endocardial maps, and studies of the excised muscles in vitro. Conclusions: Delayed afterdepolarization-induced tri ggered activity is the mechanism of VT in this mitral valve prolapse p atient, The trigger is provided by isolated ventricular premature comp lexes elicited by a different electrophysiologic mechanism, possibly r eentry, which is related to stretch and presumably to fibrosis of the papillary muscles.