Electrohydraulic ventricular assist device development.

A 64 ml (effective stroke volume) in vitro electrohydraulic ventricular assist device (VAD) prototype has been built. The energy converter is an axial flow pump driven by a brushless direct current (DC) motor. Systole begins as silicone oil is pumped from the volume displacement chamber (VDC) into the ventricle, displacing the flexing diaphragm separating the oil and the blood. In diastole, the motor reverses, providing active filling by pumping oil from the ventricle into the VDC. The surface mount electronic internal controller provides motor commutator, energy management, telemetry, and physiologic control functions. Energy is supplied externally by either a 12 V DC power supply or a 12 V DC rechargeable battery and is transmitted through the skin by a transcutaneous energy transformer (TET). Energy can also be supplied by a 12 V DC rechargeable internal battery. Bidirectional infrared telemetry is used to transmit information between the internal and external controllers.