Modeling of the human circulatory system with an axial flow ventricular assist device

This paper presents an integrated state space model of human circulatory system with a brushless DC axial flow left ventricular assist device (VAD). The developed integrated model combines a network type hybrid model of the circulatory system with the nonlinear dynamic model of the brushless DC pump. The model, though simple, preserves essential characteristics such as non-linearity, pulsativity and discontinuity due to the effects of the heart valves and the pump dynamics. Computer simulations of the circulatory system for different pathological conditions ranging from the normal heart to left heart asystole and physical scenarios ranging from rest to exercise were used to validate the accuracy and adaptability of the model. A simple PI controller was designed for the VAD, that adequately increased the cardiac demand for widely varying pathological conditions.