The authors studied the outcome of multi-organ failure in 29 patients with terminal cardiac failure and maintained with a Cardiotest total artificial heart whilst waiting for cardiac transplantation. Pre-implantation organ dysfunction was defined by the following criteria; assisted respiration of over 3 days, total billirubin and creatinine levels of over 2 mg/dL, a platelet count of less than 80,000/mL or a prothrombin ratio of less than 50% and central nervous system disturbances. Fourteen patients died during the period of circulatory assistance and 71% of deaths were due to multi-organ failure. Pre-implantation plasma total bilirubin levels were significantly higher in patients who died of multi-organ failure (p = 0.04). Eighty per cent of patients who died of multi-organ failure had at least 3 criteria of organ dysfunction before implantation of the artificial heart compared with only 37% in the other patients (p = 0.04). Finally, systemic vascular resistances before implantation were significantly lower in patients who died of multi-organ failure. The results of this study suggest that multi-organ failures does not develop during the period of circulatory assistance but represents an aggravation of a preexisting morbid condition. This observation should lead to a limitation of the indications of total circulatory assistance in some cases and, above all, to earlier intervention before multi-organ failure becomes irreversible.