Natural history of asymptomatic mitral valve prolapse in the community

The outcome of mitral valve prolapse (MVP) is controversial, with marked discrepancies in reported complication rates. We conducted a community study of all Olmsted County, Minn, residents first diagnosed with asymptomatic MVP between 1989 and 1998 (N=833). Diagnosis, motivated by auscultatory findings (n=557) or incidental (n=276), was always confirmed by echocardiography with the use of current criteria. End points analyzed during 4581 person-years of follow-up were mortality (n=96, 19+/-2% at 10 years), cardiovascular morbidity (n=171), and MVP-related events (n=109, 20+/-2% at 10 years). The most frequent primary risk factors for cardiovascular mortality were mitral regurgitation from moderate to severe (P=0.002, n=131) and, less frequently, ejection fraction or =40 mm, flail leaflet, atrial fibrillation, and age > or =50 years (all P or =2 secondary risk factors (n=250) had mortality similar to expected (P=0.20) but high cardiovascular morbidity (6.2%/y, P