Critical review of automatic control of total artificial heart

Abstract

Essential requirements for automatic control system of total artificial heart are to balance the 2 pumps and to increase cardiac output when required by the body. Intrinsic control system balances 2 pumps and increases outflow as a function of filling pressure without sophiciticated control device. However, cardiac output by this method is inadequate because outflow increases only by onetenth as much as the natural heart. Extrinsic control system via aortic pressure, atrial pressure, mixed venous oxygen tension or p-wave in the remnant atrium provides more adequate cardiac output. However, the obstacle of this method is lack of a stable, reliable and implantable pressure or blood gas transducer. To overcome the current problems the following control systems are proposed: (1) Intrinsic control system for an implantable pump and external drive unit. Intrinsic control system only is enough for the patient with restricted activity by a drive line. (2) Extrinsic control system via p-wave or blood volume in the pump for an implantable pump, drive system and sensor. Extrinsic control policy should be included to meet patient's greater activities enabled by totally implantable system. P-wave and blood volume in the pump can be measured by the current technique.