The Biomedicus centrifugal pump was required to provide prolonged ventricular support to 13 patients with hemodynamic instability: 11 after cardiovascular surgical procedures, 1 after myocardial infarction and 1 after failure of a heart transplant. The duration of support ranged from 3.5 hours to 9 days (mean 72 hours). Complications included bleeding in six patients, renal insufficiency in three and central nervous system deficit in three. Six patients (46%) were successfully weaned from the pump. The patient with graft failure had hyperacute rejection of a second heart. Five patients were discharged from the hospital. There was one death 8 months postoperatively. Prolonged ventricular support with the centrifugal pump may allow recovery of potentially reversible ventricular dysfunction in selected patients after cardiac surgical procedures.