Between November 1989 and September 1990, a cardiomyoplasty procedure was performed in 12 male patients with a mean age of 59 years. All patients were in New York Heart Association class III. Reinforcement cardiomyoplasty was isolated in 4 patients and associated with a cardiac procedure in 8. There were no perioperative deaths. Failure of cardiomyoplasty occurred in 5 patients because of recurrence of disabling congestive heart failure: 3 patients died late, and 2 had heart transplantation. The actuarial survival rate was 83% at 1 year and 73% at 2 years. Hemodynamic studies were done preoperatively in all patients, at 6 months postoperatively in 11 patients, at 1 year in 8, and at 2 years in 7. At the 2-year follow-up, 6 of the 7 survivors who did not have transplantation were functionally improved with reduced medical treatment. The following indices improved significantly at the 2-year evaluation compared with baseline: exercise capacity (63 +/- 13 W versus 83 +/- 17 W); left ventricular (LV) end-diastolic pressure (20 +/- 7 mm Hg versus 11 +/- 5 mm Hg); and angiographic LV ejection fraction (0.25 +/- 0.09 versus 0.40 +/- 0.15). Pulmonary artery pressure, pulmonary capillary wedge pressure, and cardiac index remained unchanged. Four patients underwent beat-to-beat analysis of LV function at 2 years; during skeletal muscle stimulation, stroke volume increased by 7% to 35% and LV end-systolic pressure, by 5% to 9%. In the 5 patients with failed cardiomyoplasty, mean pulmonary artery pressure and LV end-diastolic volume were higher preoperatively than in the 7 survivors.(ABSTRACT TRUNCATED AT 250 WORDS)