[When should mitral valve prolapse be considered a real disease?].

Mitral valve prolapse should be considered as a disease when superior displacement of the mitral leaflets during systole is more than 2 mm with a maximal leaflet thickness of at least 5 mm. Using these criteria, the prevalence of mitral valve prolapse is 1.3% in the general population, nearly the same in men and women. Serious complications may occur during follow-up with a 1 to 3% patient-year risk. The most important complication is mitral regurgitation, mainly due to rupture of the chordae tendineae, which must be quickly corrected by surgical repair. Second is infective endocarditis, a complication which may occur particularly in men older than 45 years of age with systolic murmur. Arrhythmias are not infrequent but ischemic neurologic events are unusual, especially in young patients. Cases of sudden death have occasionally been reported.