To identify factors affecting the successful bridge to transplantation, experience with 32 recipients of the Jarvik-7 artificial heart was reviewed. Between patients with and without a successful bridge, there were no significant differences in preoperative hepatorenal function or postoperative hemodynamics, but there were significant differences in body size. When recipients were divided according to body surface areas of less than or greater than 1.8 m2, the smaller patients more frequently developed respirator dependence (73% vs. 18%, p less than 0.01), renal failure (53% vs. 18%, p less than 0.05), and hepatic failure and sepsis, resulting in less frequent qualification for transplantation (20% vs. 65%, p less than 0.05). There were no successful bridge operations in seven patients with body surface areas of less than 1.7 m2, and only one success in nine patients who were less than 170 cm in height, despite use of a smaller stroke volume model. The smaller patients had poorer ventricular filling, which was largely compensated for by the drive controls set for significantly longer diastole and higher vacuum, resulting in similar hemodynamics between the groups. The results suggest that device fitting as manifested by body size is an important factor affecting major organ recovery and subsequent transplantation in recipients of the Jarvik-7 artificial heart. A paracorporeal device may be advisable for patients with body surface areas of less than 1.8 m2 or who were less than 175 cm in height until an even smaller model with a better fit in the thorax becomes available.