Improvement in congestive heart failure and left ventricular function after dynamic cardiomyoplasty has been reported in patients with severe cardiomyopathies, but the long-term effects of this procedure remain unclear. In this investigation 31 patients undergoing cardiomyoplasty for treatment of idiopathic dilated cardiomyopathy were annually investigated with radionuclide scintigraphy, Doppler echocardiography, and right-sided heart catheterization. They were in New York Heart Association functional class III or IV before the operation. No hospital deaths occurred, but one patient with progressive heart failure required urgent heart transplantation 42 days after cardiomyoplasty. The other patients were followed up from 6 to 70 months (mean 25.6 months) and 12 patients died at late follow-up. Actuarial survivals were 86% at 1 year, 61.4% at 2 years, and 42.5% at 3 to 5 years of follow-up. Multivariate analysis of factors influencing outcome showed that long-term survival was significantly affected by preoperative functional class and pulmonary vascular resistance. Functional class improved from 3.2 +/- 0.4 to 1.7 +/- 0.7 in the surviving patients (p < 0.01). Furthermore, left ventricular ejection fraction improved from 19.8% +/- 3% to 23.9% +/- 7.2% (p < 0.01), and significant changes in stroke index, arterial pressure, pulmonary wedge pressure, and left ventricular stroke work index were also found at 6 months of follow-up. In the late postoperative period, the left ventricular ejection fraction tended to decrease and returned to preoperative levels at 5 years, whereas hemodynamic variables did not change significantly. Thus, despite the tendency of the left ventricular ejection fraction to decrease at late follow-up, the long-term course of these patients seems to be characterized by the maintenance of hemodynamic improvement. However, long-term survival after cardiomyoplasty is limited by the severity of the patient's condition before the operation.