Control system for circulatory assist devices: determination of suitable control variables.

This paper studies the problem of identification of suitable biological variables for optimal effectiveness of a CAD. To identify suitable error signals, a closed loop simulation and analysis of the assisted circulation was carried out. Results show that the combination of heart rate and left atrial pressure is very effective as an input error signal for either series or parallel assisted circulation when simulated heart failure is severe (greater than 50% decrease in left ventricular elastance). During simulated exercise (50% reduction in peripheral resistance) such a combination is even more effective. In addition, simulation results show that aortic pressure and cardiac output are not suitable control variables for CAD.