[Progression of idiopathic mitral valve prolapse estimated by echocardiography].

To evaluate the progression of idiopathic mitral valve prolapse (MVP), a long time follow-up study (mean 7.1 years) was performed using echocardiography in 27 cases (11 males, 16 females, mean age: 50.4 years). Morphological changes, the degree of prolapse of the mitral valve, left atrial dimension (LAD) and left ventricular end-diastolic dimension (LVDd) were estimated at the first and last examinations. The degree of prolapse was assessed by measuring the distance of the dislocation between the anterior and posterior leaflets at the area of coaptation (degree I:5 mm or less, degree II: 6 to 10 mm, degree III: 11 mm or greater). The results were as follows: 1. The degree of prolapse did not progress in all 27 cases. 2. LAD increased with an advance of age. A remarkable increase of LAD was recorded in cases older than 45 years with atrial fibrillation or prolapse of degree II and III or with ruptured chordae tendineae. 3. The mitral ring was enlarged over 5 mm in six of 15 cases with prolapse of degree II and III. 4. Mitral regurgitation evaluated by Doppler echocardiography in patients with posterior leaflet prolapse was more severe than that in patients with anterior leaflet prolapse in the last examination. 5. LVDd increased gradually. In the present study, LAD was increased in most cases of MVP and it seemed to depend on complications (atrial fibrillation and ruptured chordae tendineae) or severity of regurgitation rather than the degree of prolapse.