Follow-up observations in patients with mitral valve prolapse.

The discrepancies reported in various studies with respect to long-term prognosis in mitral valve prolapse can be attributed to the criteria employed for diagnosis and to the differing patient populations studied. Furthermore, mitral valve prolapse is not a single, well-defined disease but reflects rather a broad spectrum of a disease process. Echocardiographically, patients can be identified with redundant, thickened leaflets with excessive mitral valve motion and prolapse as well as those with normal appearing leaflets but systolic prolapse representative of differing disease processes with differing prognosis. The incidence of sudden cardiac death is estimated at a low value of 1.9/10,000 patients per year. In the presence of a normal resting ECG, with no hemodynamically-meaningful mitral regurgitation and no evidence of redundant mitral leaflets the risk is even less. Cerebral embolic events occur with an estimated incidence of 1/6000 patients per year, similarly low; it can be assumed that patients with very myxomatous, redundant mitral leaflets have the highest risk. The incidence of infective endocarditis is also low, estimated at 1/5725 patients per year (0.175%). Risk factors for complications include: a systolic murmur, advanced age, male sex and leaflet redundancy. The most important complication is mitral regurgitation for which the incidence is highest in older men and in the presence of left ventricular, dilatation.