During the last 5 years, a new pneumatically driven left ventricular assist device has been implanted in 18 heart transplantation candidates who required advanced mechanical circulatory support. The mean duration of support was 80 +/- 74 days, and the cumulative support time was 1400 days. Fifteen patients were successfully supported until the time of heart transplantation. As a result of early experience, in which three of four patients died after heart transplantation because their end-organ function failed to recover, subsequent efforts were made to institute support early, before irreversible organ damage occurred. Eleven of the 12 patients in the later experience are currently alive and well at a mean follow-up of 12.6 +/- 7.5 months. No thromboembolic episodes occurred, and minimal anticoagulation was required. Furthermore, patients were able to participate in rehabilitative exercise programs, thus optimizing their transplantation status. Finally, the findings in these patients have shown the feasibility of providing long-term, or even permanent, cardiac assistance.