Estimation of a physiologic strategy based on a mathematical model for assisting and substituting cardiac functions by a robotic artificial heart

In order to assist and substitute diseased cardiac functions, it is important to develop a robotic artificial heart capable of adapting to physiologic changes in the same way the natural heart does. In this paper, we propose a method of estimating a physiologic strategy based on the systemic circulation model in order enable the effective medical care and therapeutic control using an artificial heart. The physiologic strategy is estimated by the internal physiologic parameters identified from a mathematical model using online parameter identification with the δ operator and the resonant frequency is calculated from the identified physiologic parameters. In the computer simulation study, the physiologic parameters and the resonant frequency could be identified precisely. During the animal experiment, the estimated physiologic parameters and resonant frequency corresponded to the physiologic changes. In the terminal stage of the animal experiment, the physiologic parameters were changed — mean peripheral resistance was increased from 0.4 to 1.0 mmHg s/ml and mean aortic compliance was decreased from 0.50 to 0.20 mmHg/ml. The resonant frequency was synchronized with the heart rate. As a result, we estimated the physiologic strategy as the changes in the identified physiologic parameters online to assist and substitute diseased cardiac function by a robotic artificial heart.