Background: The long-term result following heart transplantation appears very good despite complications of coronary atherosclerosis and cancer. Critically ill patients supported with mechanical devices remain a growing and difficult group in which longterm results need to be defined. The objective of this study was to review the 10-year follow-up of critically ill patients who underwent heart transplantation after support with mechanical devices. Methods: We retrospectively analyzed all patients who underwent heart transplantation from 1986 to 1999 at the Montreal Heart Institute. Results: Twenty-two patients (22/199, 11%) underwent heart transplantation after support with intra-aortic balloon pumps (n = 17) and total artificial hearts (n = 5). One hundred seventy-seven patients (177/199, 89%) underwent heart transplantation without pre-operative mechanical assistance. Patients with pre-operative mechanical assistance were younger (41 +/- 12 vs 48 +/- 10 years old, p = 0.002), underwent a shorter waiting time to transplantation (2 +/- 2 vs 19 +/- 27 weeks, p = 0.004), and donor hearts had longer ischemic time (166 +/- 63 vs 137 +/- 49 minutes, p = 0.002) compared with patients without pre-operative mechanical assistance. One-month, 1-, 5-, and 10-year survival averaged 86% +/- 7%, 67% +/- 10%, 67% +/- 10%, and 59% +/- 12%, respectively, in patients with pre-operative mechanical assistance compared with 95% +/- 2%, 88% +/- 2%, 81% +/- 3%, and 74% +/- 4%, respectively, in patients without assistance, a significant difference (p = 0.04) that is mainly related to higher operative mortality in the former group. Although, we found no difference between the 2 groups in the 10-year freedom rate from acute rejection, infection, cancer, and coronary atherosclerosis, sepsis was the cause of 4 early deaths among patients with preoperative mechanical assistance. Conclusion: Early and long-term survival was significantly decreased in critically ill patients with pre-operative mechanical assistance compared with other patients without pre-operative assistance. Sepsis is a dominant threat among patients who underwent heart transplantation with pre-operative mechanical assistance, and the lower survival is due mainly to the increased early mortality.