Mechanical circulatory support systems are currently in clinical use to keep patients alive with the aim of either cardiac recovery after open heart surgery, myocardial infarction and after heart transplantation with acute graft failure, or as a bridge to transplantation in heart transplant candidates. At the German Heart Institute the "Berlin Heart" mechanical circulatory support system has been used invariably since 1987. Up to 1991 there were 22 patients in the "recovery" group. Four patients could be weaned from the system, but only one patient was discharged from the hospital. In 65 patients mechanical circulatory support systems were implanted as a bridge to transplantation, 39 patients had transplants, and 22 patients left the hospital. Risk factor analysis in the bridging group revealed that previous heart surgery, infective pneumonia, shock-related coagulation disorders, and an age greater than 50 years had an unfavorable influence on patient survival. It is concluded that patients may be kept alive for weeks and months after any kind of cardiogenic shock. Complete cardiac recovery may be achieved in the case of early posttransplant graft failure. Reliable prediction of outcome in the bridge to transplantation group requires further experience.