Malignant ventricular arrhythmias in patients with mitral valve prolapse and mild mitral regurgitation.

Mitral valve prolapse (MVP) is a common disorder that, in general, has a good prognosis. Rare occasions of sudden death have been reported in patients with MVP and it is presumed that the basis of sudden death is arrhythmic. We report seven patients with moderate to severe MVP and malignant ventricular arrhythmias. All patients had trivial to mild mitral regurgitation and normal left ventricular function. Three patients presented with syncope, two with out-of-hospital cardiac arrest, and three with recurrent palpitations and presyncope. In a mean follow-up period of 2.5 years (range 6 months to 5 years), two patients died suddenly despite successful control of their nonsustained ventricular tachycardia (VT) with sotalol as shown by ambulatory monitoring. Two patients, who had sustained VT despite antiarrhythmic drug therapy, had mitral valve surgery, however, monomorphic VT could be induced in both even after surgery. The arrhythmias in the remaining three patients are controlled on antiarrhythmic drugs. We conclude that a selected subset of patients with MVP, malignant ventricular arrhythmias, and mild mitral regurgitation are at risk of sudden death. Syncope, inferolateral repolarization changes, complex ventricular ectopy, and a markedly myxomatous valve may be pointers to higher risk of sudden death and mitral valve surgery may not provide control of ventricular arrhythmias.