A Low Order Analogue Circuit to Simulate Cardiovascular System Hemodynamics

In this study a third-order electrical analogue of the cardiovascular system (CVS) is presented, where pressures, volumes and flows are represented by voltages, charges and currents, respectively. The left atrium and the elastic arteries and veins are modeled as capacitive elements (reservoirs) with constant compliance (C) while the left ventricle is modeled as a capacitive element with variable elastance (e = 1/C), and vascular resistances are modeled as resistive (R) elements. The circuit is simplified by lumping together systemic arteries, arterioles and capillaries in the aortic; systemic veins and capillaries, right atrium and ventricle, and pulmonary arteries in the venous; and pulmonary capillaries and veins into the left atrial compartments. The state variables are chosen as the pressures of the left atrium, left ventricle and aorta. Although the model does not include major physiological feedback mechanisms such as neuro-hormonal pathways or the coronary arterial system, cardiac hemodynamics are simulated with high accuracy. This model is intended to be taken as the template for a bench-top physical platform to test the pre-clinical performance of novel Left Ventricular Assist Devices placed parallel to the LV and AO in future studies.