A novel electromechanical drive for a tether-free implantable ventricular assist device

A tether-free ventricular assist device (VAD) based on a novel electromechanical drive was prototyped and evaluated. The unit can be adapted for implantation. The device utilizes a bladder-type ventricle taken from a pneumatically driven VAD. In mock loop testing, the unit has met the design capacity of 6 L/min against a pressure head of 150 mm Hg. The efficiency of the device allows it to operate at design flow and pressure for periods of up to 8 h when powered by a single rechargeable battery pack weighing less than 5 kg. The mechanism consists of a seamless sac-type bladder situated between hinged plates actuated by a motor-driven bell-and-crank linkage. Cycle parameters are controlled by a microprocessor-based servomotor drive.