Hemodynamic Modeling of the Cardiovascular System

Callie Maples
cm9@cec.wustl.edu

Under the Supervision of:
Dr. Ilker Tunay
Stereotaxis, St. Louis, MO


Abstract

A simulation model of the cardiovascular system has been developed that is easily adaptable for a variety of conditions and subjects. The model is a crucial piece in a larger project whose ultimate goal is to develop a localization signal for a medical device in a patientís heart that filters out interfering signals from respiration and the beating of the heart. This report includes a full derivation of the model as well as the logic behind a Simulink implementation. In addition, a variety of different scenarios were simulated for humans, including normal conditions, exercise, sleep, pulmonary embolism, systemic hypertension, myocardial infarction, and arrhythmia. In addition, a canine model was developed, and simulations were conducted for normal conditions and arrhythmia. The cardiovascular model yields results within normal ranges for the normal condition simulations, and the scenario modeling trends mirror those found in real subjects. This model should provide a solid basis for future development of the project.

Goal

Modeling Approach

The pressure-volume approach divides the cardiovascular system into a series of elastic chambers, each with its own resistance. This pressure volume approach was chosen for the relatively small number of parameters required and because these parameters can easily be adapted for a wide range of subjects.

Matlab and Simulink are used to implement this approach because of the convenience of Simulink for simulating such physical processes. In addition, Matlab is widely available and will probably be used for future work in this project.

Model Derivation

Several sub models were needed to create the full cardiovascular model:

Scenario Simulations

Once the cardiovascular model was completed, a variety of scenarios were simulated to determine the reliability and applicability of the model.

Summary of Results

Conclusion

The goal was to produce a model of the cardiovascular system that is easy to adapt to a wide range of conditions and subjects. This goal has clearly been demonstrated through the simulation of several different scenarios in humans and canines.