Successful mitral valvuloplasty using the Inoue balloon in a patient with mitral stenosis associated with subvalvular fibrosis and reduced left ventricular inflow cavity: a case report. Percutaneous transvenous mitral valvuloplasty (PTMV) was performed with two cylindric pigtail balloon catheters in a 52-year-old woman with symptomatic mitral stenosis. The subvalvular apparatus was fibrous with welded chordae and the subvalvular left ventricular space was markedly reduced. As a result of this distorted anatomy, during the inflations, the two balloons constantly slipped back into the left atrium before full inflation was obtained. After the procedure, the mitral valve area (MVA), as estimated by echo-doppler (ED), increased from 1.00 to 1.34 cm2. After 2 months of mild clinical improvement, the patient again became symptomatic and ED examination showed a MVA of 1.25 cm2. A second PTMV was performed with an Inoue balloon, the entire procedure taking less than 1 hour. A stable position of the Inoue balloon and complete dilatation were achieved. ED examination showed a mitral valve area of 2.30 cm2. There was no mitral regurgitation nor atrial septal defect. After 3 months, she has only N.Y.H.A. class I symptoms and MVA, as estimated by ED, was 2.40 cm2. 