[Mitral valve prolapse in patients with myocarditis and collagen diseases]

The purpose of this study is to investigate mitral valve prolapse (MVP) in patients with suggested endomyocardial disorder. The study population consisted of 24 patients (group M) aged 41 +/- 17 years old, who were suspected or confirmed to have the history of myocarditis and 45 patients (group C) with collagen disease aged 42 +/- 14 years old. All patients had no left ventricular (LV) hypertrophy, no LV dilatation, and normal systolic function of the LV. Thirty normal subjects (group N) aged 43 +/- 17 years old were used for the control study. In both groups M and C, cardiac symptoms were observed in 54 and 53%, ECG abnormalities in 58 and 38%, and ventricular premature contractions of 3 or 4 degree by Lown's classification in 46%, respectively. M-mode measurements (LVDd, LVDs, %FS, LAD, IVST+PWT) were not different among three groups. MVP were detected in 54% of group M and in 49% of group C. Left ventricular peak filling velocity in the atrial contraction phase (A) divided by the peak filling velocity in the rapid filling phase (R) was significantly higher in groups M and C than in group N. There was no difference in clinical features and echo findings except for the frequency of mitral regurgitation between patients with and without MVP. Thus, MVP was frequently observed in patients with myocarditis and patients with collagen diseases, who were both suspected to have endomyocardial damages. It is suggested that in these patients, MVP might be caused by post-endomyocarditis lesion of the mitral apparatus.