Date of Award

Spring 1996

Document Type

Thesis

Degree Name

Master of Science in Biomedical Engineering - (M.S.)

Department

Biomedical Engineering Committee

First Advisor

Arthur B. Ritter

Second Advisor

David S. Kristol

Third Advisor

Kamalesh K. Sirkar

Abstract

A mathematical model of human cardiovascular system is presented in this study. The closed-loop model is composed of twenty compartments which includes the left and right ventricles, and the systemic and pulmonary circulations. Two physiologic feedback control mechanisms, autoregulation of blood flow and baroreceptor reflex regulation of arterial pressure, are incorporated in the model. Autoregulation acts by changing local resistance to blood flow through metabolic and myogenic mechanisms, thereby insuring a match between oxygen supply and demand for any tissue or organ. Baroreceptors act through neural pathways to alter heart rate, contractility and peripheral resistance in order to return sudden changes in blood pressure to a normal "set point". Pressure and volume waves in a simulated normal human at rest throughout the systemic circulation were generated. Parameters of the model were set to simulate heart failure in two stages. The effects of autoregulation on the coronary circulation with the changes in ventricular contractility, heart rate and peripheral resistance were studied. The results suggest that the oxygen consumption rate of the coronary circulation is mainly affected by afterload. Maximizing ventricular contractility and peripheral resistance, and minimizing heart rate were shown to improve ventricular coronary vascular reserve.

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