The AbioCor is a revolutionary device. It is the only device of its kind in the clinical world. The role of the AbioCor is to provide permanent replacement of the failing heart for patients who are not transplant candidates. The clinical trial has been successful in the majority (four of seven) of patients implanted thus far. Eight more patients are required to complete the initial feasibility phase of the trial, afterwhich it remains to be seen if the trial will expand to additional patient populations. The powerful features of the pump have been demonstrated in the extremely sick group of candidates that enrolled in the study. The TET system has worked extremely well. Lastly, the milestone of discharging a patient to home on a completely internal artificial heart has been realized. The profile of CardioWest is very different from AbioCor. Although both were initially designed as permanent replacement therapies, the CardioWest has been extremely useful as a bridging device, and it may have a broader application in the future. For the CardioWest, the most favorable groups are patients with cardiomyopathy who decompensate while awaiting transplantation. On the other hand, the AbioCor is indicated in nontransplant candidates with biventricular failure who have a less than 30-day predicted survival. Proper patient selection is critical to achieving success with either device.