 It has been used in over thirty patients to date.Pierce's artificial-organs group subsequently focused on a completely implantable electromechanical artificial heart consisting of two prosthetic blood pumps actuated by pusher plates driven by a compact DC motor.This biventricular heart pump, with its microprocessor-based digital control system, transcutaneous energy transfer system, and implanted compliance sac, has been successfully used in numerous calf implant studies.