In Vitro Development of Automatic Control for the Moving-Actuator Type Total Artificial Heart (TAH)

The in vitro development of an automatic control method for the moving-actuator type total artificial heart (TAH) was the goal of this study. The control strategy was set up with two principles: no compliance chamber and no transducer. Without any transducer, motor current provides information to be used as an input to the automatic control system. Based on the analysis of motor current waveforms, the automatic control method developed maintains the optimal heart rate in terms of maximal cardiac output delivery under given venous return. Also, in the moving-actuator mechanism, the stroke volume of one ventricle can be less or more than that of the other through adjustment of the asymmetry of the actuator stroke angle. The automatic control method developed was tested on a mock circulatory system. Over a physiological range of preload (0 to 15 mmHg right atrial pressure [RAP]) and afterload (80 to 120 mmHg aortic pressure [AoP]) the cardiac output response varied from 5 to 91/min with the left atrial pressure (LAP) maintained within levels approximately 5 mmHg higher than the RAP.