Mitral balloon valvuloplasty was performed in 14 patients with recurrent mitral stenosis 16.9 +/- 1.8 years (range 6 to 30) after surgical commissurotomy. There were 13 women and 1 man with a mean age of 55 +/- 4 years (range 23 to 73). Mitral balloon valvuloplasty resulted in an increase in mitral valve area from 0.8 +/- 0.1 to 1.7 +/- 0.2 cm2 (p = 0.001), a decrease in mean mitral diastolic pressure gradient from 15 +/- 2 to 7 +/- 1 mm Hg (p = 0.001) and an increase in cardiac output from 3.4 +/- 0.3 to 3.9 +/- 0.3 liters/min (p = 0.03). No deaths, strokes, vascular complications or conduction abnormalities were observed. Mitral regurgitation developed or increased in severity in seven patients (50%). There was no evidence of significant left to right shunt through the atrial septal puncture site after mitral balloon valvuloplasty. A good result (defined as a mitral valve area greater than 1.0 cm2, an increase in mitral valve area greater than 25% and a mean gradient less than 10 mm Hg) was achieved in 9 (64%) of the 14 patients. A subgroup of four patients who had a superior result (increase in mitral valve area of 1.7 +/- 0.2 versus 0.5 +/- 0.1 cm2 in the other 10 patients, p = 0.004) was identified. These patients had less echocardiographic evidence of rheumatic mitral valve damage and were the only patients who had sinus rhythm. They were also younger, less debilitated and had a lower grade of fluoroscopic valve calcification compared with the other patients. Thus, mitral balloon valvuloplasty is a safe and effective procedure for patients with recurrent mitral stenosis after surgical commissurotomy.(ABSTRACT TRUNCATED AT 250 WORDS)