Simulation Of The Cardiovascular Hemodynamics Using Coupled Linear Models

Abstract

The purpose of this paper is to model the main hemodynamic variables and parameters using the MATLAB environment. The SIMULINK simulation schema is based on the analogy between the blood flow dynamics end the defining elements of the electric circuits. The adopted nonlinear, lumped parameter model comprises: a four-element modified windkessel model to represent the systemic circulation; a time-varying capacitor used to represent the left ventricle; a single constant capacitance to represent the pulmonary circulation and left atrium; two diodes in series with resistors to model the heart valves.
The proximal aortic pressure represents the input signal of the model. The simulation was made after dividing the cardiac cycle in four time intervals; each of them has a linear subsystem representation of the blood flow. Successive coupling of these models covered the entire cardiac dynamics.
The simulated variables were compared to physiological counterpart in order to validate the model. Finally it was made a brief analysis concerning the utility of the model for the identification purpose