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 clearly understood. To determine the site-related differences in regression and progression of MVP, 112 patients with idiopathic MVP were enrolled in this echocardiographic follow-up study. Cardiovascular complications, including dysarrhythmias (n = 3, 2.7%), overt congestive heart failure (n = 4, 3.6%), progression of mitral regurgitation over one grade (n = 28, 25.0%), newly 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 revealed that posterior leaflet prolapse and significant mitral regurgitation (grade >/=2) were considerable risks for cardiovascular complications. Regression of MVP was seen in 17 (18.7%) of the anterior prolapse patients; however, new prolapse was observed in 40 (35.7%) patients, mainly in posterior prolapse patients. These results suggest that site-related differences exist in uncomplicated MVP prognosis and that MVP in the posterior leaflet has a poor outcome compared to that in the anterior leaflet.