Long-term site-related differences in the progression and regression of the idiopathic mitral valve prolapse syndrome

The natural history of uncomplicated mitral valve prolapse (MVP) is not cle arly understood. To determine the site-related differences in regression an d progression of MVP, 112 patients with idiopathic MVP were enrolled in thi s echocardiographic follow-up study. Cardiovascular complications, includin g dysarrhythmias (n = 3, 2.7%), overt congestive heart failure (n = 4, 3.6% ), progression of mitral regurgitation over one grade (n = 28, 25.0%), newl y confirmed chordal rupture (n = 1,0.9%), and surgical repair (n = 2, 1.8%) , were observed in these patients during a follow-up period of 1-13 years ( mean, 4.0 +/- 2.8 years). Multivariate analysis and Kaplan-Meier analysis r evealed that posterior leaflet prolapse and significant mitral regurgitatio n (grade greater than or equal to 2) were considerable risks for cardiovasc ular complications. Regression of MVP was seen in 17 (18.7%) of the anterio r prolapse patients; however, new prolapse was observed in 40 (35.7%) patie nts, mainly in posterior prolapse patients. These results suggest that site -related differences exist in uncomplicated MVP prognosis and that MVP in t he posterior leaflet has a poor outcome compared to that in the anterior le aflet.