Mitral Valve Prolapse and Arrhythmic Sudden Death

Abstract

Mitral valve prolapse (MVP) can be a cause of arrhythmic sudden death (SD). Among 650 people (<40 years old), who died suddenly and were recorded in the Registry of the Veneto Region (ITALY), 43 (25 females, age range 19-40 years) resulted at autopsy affected by mitral valve prolapse (7% among all causes of SD), in the absence of any other heart disease. Left ventricular myocardial fibrosis was found in the myocardium of the mitral valve apparatus (papillary muscles and free left ventricular wall). The genesis of ventricular tachyarrhythmias, precipitating cardiac arrest, is a progressive fibrosis by mechanical stress of the left ventricular systole. One billion of systoles occur during our life. The mechanical stress is increased by a congenital defect of mitral leaflets with disjunction at the annulus. The abnormality is such that mitral valve prolapse should be considered a congenital heart disease. The major clinical challenge is how to identify patients with arrhythmic MVP to prevent sudden death. Cardiac Magnetic Resonance with late enhancement gadolinium and electrophysiology assessment play a fundamental role to identify myocardial fibrosis and electrical instability at risk of life threatening ventricular tachiarrhytmias. Endocardial ablation and implantable defibrillator are life-saving. Valve repair or prosthetic replacement do not protect from the risk of sudden death, which is part of the prognosis following surgery.