Immediate hemodynamic results of percutaneous mitral valvuloplasty were compared in two consecutive series of unselected patients from the same institution undergoing valvuloplasty with the double-balloon (161 patients) or the Inoue balloon (71 patients) technique. Before valvuloplasty, the patient series were comparable with regard to average age, gender repartition and most clinical, electrocardiographic, X-ray and hemodynamic variables. Poor anatomic forms of mitral stenosis were equally distributed in both series (41% vs. 45%, p = NS). The magnitude of mitral valve area increase and of mean mitral gradient decrease during percutaneous mitral valvuloplasty did not differ significantly in the Inoue balloon and double-balloon series (mean +/- SEM 1.1 +/- 0.2 to 1.95 +/- 0.5 and 1.0 +/- 0.2 to 1.97 +/- 0.5 cm2, respectively, for mitral valve area and 12 +/- 3 to 5 +/- 2 and 13 +/- 4 to 5 +/- 2 mm Hg, respectively, for mean mitral gradient). Four cases of 3+ mitral regurgitation occurred in the Inoue balloon series and 7 in the double-balloon series (p = NS). A good immediate result-defined as mitral valve areas greater-than-or-equal-to 1.5 cm2 with greater-than-or-equal-to 25% in mitral valve area gain and mitral regurgitation less-than-or-equal-to 2+ at the end of the procedure-was observed in 78% of patients in both series. Three cases of tamponade due to chamber perforation and 14 cases of transient air embolism in the right coronary system due to balloon rupture were observed in the double-balloon series. Procedure duration and fluoroscopy time were significantly shorter in the Inoue balloon series (104 +/- 13 vs. 123 +/- 23 min, p < 0.02 and 16 +/- 6 vs. 24 +/- 12 min, p < 0.02, respectively). In conclusion, the Inoue and double-balloon techniques produced equivalent results but the risk of complications and the time required for the procedure and for fluoroscopy were reduced with the Inoue balloon technique.