In the course of the studies in total heart replacement systems the authors took up the problem of output flow control of artificial hearts from the angle of control engineering and systems engineering. Here, they tentatively regarded the cardiovascular system, which was assumed to be the control object, as a closed multiport system. Then they analyzed the characteristics of the cardiovascular system as a circulatory system with bond graph designation method. On the basis of bond graph designation, mathematical and mechanical models similar to the cardiovascular system were developed. To test whether dynamic behaviors of the mechanical model were similar to those of living dog or not, the data on the model were compared with the hemodynamics of the experimental dog, whose heart was totally replaced by the authors' blood pumps. Under the same output flow condition, the hemodynamics data from the simulator and experimental dog showed high resemblance to each another. Though there remain several issues in their present models, theirs would as such be available to fundamental researches on the cardiovascular system, especially on artificial heart control systems.
