Between April 1988 and October 1989, 22 adult patients with isolated or predominant severe mitral stenosis underwent Percutaneous Transvenous Mitral Valvuloplasty (PTMV). In 20 patients, a transseptal double balloon technique was used; in the last 2 patients, dilatation was performed using the Inoué balloon. Immediately after the procedure, the mitral valve area (MVA) rose from 1.2 +/- 0.3 to 2.2 +/- 0.8 cm2 (p less than 0.0001) using the hemodynamic method and from 1.1 +/- 0.4 to 1.9 +/- 0.4 cm2 (p less than 0.0001) using a Doppler technique. The mean left atrial pressure decreased from 20.3 +/- 6.0 to 10.5 +/- 5.0 mm Hg (p less than 0.0001). After the procedure, severe mitral regurgitation or significant iatrogenic interatrial septum defect did not occur. Two cerebral accidents were observed. One patient had a severe stroke with aphasia and hemiplegia but recovered within 3 months. The other patient had a minor dysarthric event, which resolved completely after 24 hours. Three months follow-up data in 16 patients revealed that they all were in NYHA class I or II. Restenosis occurred in 1 case. In the whole group of patients the MVA calculated by Doppler examination was similar to immediately after PTMV (1.9 +/- 0.4 versus 1.9 +/- 0.7 cm2).