Implantable left ventricular assist device systems (LVAS) are increasingly being used to bridge patients to heart transplantation because of the limited number of available donor hearts. This prospective, multicenter trial was designed to evaluate the usefulness of the HeartMate vented electric (VE) LVAS as a bridge to transplantation in Japan. Between November 2001 and June 2003, six patients with end-stage heart failure [New York Heart Association (NYHA) class IV] were supported with the LVAS and five of the six were able to implement the evaluation (one dropped out). The five were men with an average age of 38.6 years and were supported for 2390 cumulative days (6.6 years). Average preimplant cardiac index improved from 1.93 l/min/m(2) to a 3.79 l/min/m(2) VAD flow index at the end of the clinical trial. All five patients improved to NYHA class I or II, survived more than 1 year, and one patient was discharged from the hospital. Mean LVAS support duration was 478 days (range 390-575 days) and four patients remain supported. One patient died from cardiac failure and sepsis. Device-related complications included: infections (four patients), thromboembolism (one patient), hemolysis (two patients), and repeat operation for bleeding (two patients). There was one case of inflow valve incompetence and two pump motor malfunctions. We conclude that the LVAS can effectively support patients as they await cardiac transplantation and offers improvement to the patient's quality of life.