Relation of mitral valve prolapse to left ventricular size in Marfan's syndrome

Sporadic recent reports suggest that mitral valve prolapse (MVP) disappears with progressive left ventricular (LV) dilatation. To test this hypothesis, we sought to determine if an inverse relation exists between MVP and LV cavity size on M-mode echocardiograms in 83 patients with Marfan's syndrome. LV end-diastolic dimensions and presence or absence of MVP were determined. Forty-six patients had MVP. Of patients with an LV end-diastolic dimension ≤ 5 cm, 90% had MVP; only 19% of the 32 patients with abnormally large (>5.8 cm) end-diastolic dimension had MVP. The prevalence of MVP in patients with an LV end-diastolic dimension of 5.1 to 5.8 cm was 69%. Thus, the prevalence of MVP was inversely related to LV cavity size. To determine whether appearance or disappearance of MVP was associated with decrease or increase in LV cavity size, serial echocardiograms from 67 patients (mean follow-up 42 months, range 3 to 99) were examined. These patients were separated into 3 groups based on changes in the LV end-diastolic dimension of >1 cm over time. Group 1 consisted of 9 patients, all of whom had MVP and normal LV cavity size on their initial study. With subsequent increase in LV end-diastolic dimension (mean 1.42 ± 0.3), MVP disappeared in 6 of the 9. Conversely, group 2 consisted of 4 patients, all of whom had dilated left ventricles on their initial echocardiogram and no evidence of MVP. After aortic valve replacement, the LV cavity size decreased (mean 2.3 ± 0.7) and MVP appeared on follow-up studies. Group 3 consisted of 54 patients with little or no change in LV end-diastolic dimension (≤ 1 cm, mean 0.4 ± 0.2 cm). In this group, MVP status remained unchanged throughout the follow-up period. Thus, in patients with Marfan's syndrome, serial increase or decrease in LV size is associated, respectively, with disappearance or appearance of MVP.