Stimulated skeletal muscle grafts have been proposed as a means to reinforce ventricular wall in the treatment of severe myocardial failure. Latissimus dorsi cardiomyoplasty was performed in 11 patients with advanced heart failure due to cardiomyopathy who were in New York Heart Association (NYHA) class III or IV despite maximal medical therapy. There were no operative deaths. Eight patients were followed for a mean of 10.8 months. Two patients remain in muscle conditioning protocol. One patient died with latissimus dorsi ischemia and congestive heart failure. Four of the eight patients in long-term follow-up are in NYHA class I, three in class II, and one in class III. At 3 months of follow-up, rest radioisotopic left ventricular ejection fraction increased from 20.5 +/- 3.6% to 26.8 +/- 8.1% (p less than 0.01). Doppler-echocardiography demonstrated that left ventricular segmental wall shortening improved from 11.3 +/- 2.5% to 16.5 +/- 3.9% (p less than 0.01) and left ventricular stroke volume from 22.9 +/- 4.6 to 33.1 +/- 10 ml (p less than 0.01). Cardiopulmonary exercise test showed that maximal oxygen consumption during treadmill test increased from 14.8 +/- 3.7 to 18.2 +/- 3.3 ml/kg.min (p less than 0.05). At 6 months of follow-up, all the above values remained essentially unchanged. Furthermore, nonsustained ventricular tachycardia was abolished without specific medical therapy in four patients. Thus, cardiomyoplasty improves left ventricular function, reverses congestive heart failure, and may improve long-term survival in severe cardiomyopathies.