Development of the physiological control scheme for an electrohydraulic total artificial heart

A totally implantable artificial heart actuated by an electrohydraulic energy converter is described, and the requirements for its physiological control scheme are listed. Based on these specifications and on previous work on control schemes for the electrohydraulic total artificial heart, preliminary experiments were conducted which confirmed the feasibility of the proposed control scheme for the current device configuration. Experiments were conducted by attaching an electrohydraulic ventricle to pump the right side, and a pneumatic U-100 ventricle along with its drive and monitoring unit to pump the left side of an instrumented Donovan mock circulation. Each ventricle was controlled by manually adjusting its heart rate, percent systole, and drive pressures/motor speeds until the left and right atrial pressures were within 4 mmHg of each other, i.e. until the two sides of the circulation were balanced. The pressure waveforms sensed in the base of the electrohydraulic ventricle were recorded for a range of cardiac outputs (4-8.5 l/min) and of left atrial pressures (4-11 mmHg)