Percutaneous balloon valvotomy for patients with mitral stenosis: initial and follow-up results. Percutaneous double balloon mitral valvotomy (PMV) was performed in 25 patients with severe mitral stenosis who were followed for at least 6 months after the procedure. There were 22 women and 3 men, with a mean age of 51 +/- 14 years (range, 27 to 74). Hemodynamic and angiographic findings were evaluated before and after PMV and clinical status was assessed at follow-up. There was a significant decrease in mitral gradient following PMV, from 15.4 +/- 5.1 to 5.0 +/- 2.6 mm Hg (p less than .0001); an increase in cardiac output, from 4.6 +/- 1.1 to 5.2 +/- 1.1 L/min (p less than .01); and an increase in calculated mitral valve area, from 0.9 +/- 0.2 to 2.2 +/- 0.6 cm2 (p less than 0.0001). Mitral regurgitation developed or increased in severity in six patients (24%). At the time of follow-up (mean, 12 +/- 5 months), three patients required elective mitral valve replacement for symptomatic mitral regurgitation and 91% (20 of 22) of the remaining patients had continued improvement in functional class. PMV can safely be performed in properly selected patients with symptomatic mitral stenosis with good immediate and follow-up results. 