In order to study the results of percutaneous mitral valvuloplasty (PMV), subvalvular mitral disease was classified using: 1) the transthoracic echo score (0-4), 2) an index derived from left ventricular angiography defined as the ratio of the distance from the extremity of the papillary muscle and the mitral valve in systole and the distance between the beginning of the aortic root and the apex of the left ventricle in diastole. This index of subvalvular fibrosis could be measured in 80 out of our first 103 PMV performed without complication; the mitral surface are a increased from 1.1 +/- 0.4 to 2.2 +/- 0.8 cm2 (p less than 0.0001). After PMV, mitral regurgitation was observed or was aggravated in 28 patients (35%), by one grade in 25 and by more than one grade in 3. The overall echo score was 8.3 +/- 1.5 and that of subvalvular fibrosis was 2 +/- 0.6. The angiographic index of subvalvular fibrosis was 0.18 +/- 0.04. No correlation was observed between echo and angiographic appreciation of subvalvular fibrosis. Multivariate analyses were selected: 1) the overall echocardiographic score (r = -0.45, p less than 0.0001), but not the angiographic index of subvalvular fibrosis or echocardiographic score of subvalvular fibrosis, was predictive of increase of valve surface area; 2) the absence of mitral regurgitation before PMV (p less than 0.01) and an angiographic index of subvalvular fibrosis less than or equal to 0.15 (p less than 0.03) were predictive of increased mitral regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)