From July 1989 to May 1992 16 patients received circulatory support with a Hemopump assist device in the Department of Cardiac Surgery of the Katholieke Universiteit Leuven. The mean age of those patients was 56 +/- 13 years (ranging from 23 to 72 years). The mean time of assisted circulation was 60 +/- 46 h (ranging from 2 to 168 h). Group I consists of 13 patients who received the device after postcardiotomy cardiac failure (survival 38%). Group II includes 1 patient who received the pump prior to repair of a large postinfarction ventricular septal defect (survival 10%). Group III consists of 2 patients for whom the Hemopump was used as a bridge to cardiac retransplantation. Both are still alive (survival 100%). If the 21-F Hemopump is implanted following a critical indication it can be used rather successfully for mechanical circulatory support.