Date of Award

Fall 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

Stanley S. Reisman

Abstract

The hemodynamics of the ventricular septa] defect is studied using a mathematical modeling technique. A twelve-compartment windkessel model of cardiovascular system is used to study the hemodynamics of the ventricular septal defect. The VSD is incorporated into the model via a parallel flow from the left to right ventricles (left-to-right shunt). The resistance to flow through the shunt is used to characterize the severity of the defect. Changes in the severity of the shunt flow produces changes in the ratio of pulmonary to systemic flow in the circulation. When the pulmonary to systemic flow ratio is more than 2:1, the defect is considered large based on current clinical guidelines. A safe-limit shunt hemodynamic resistance corresponding to a ratio of 2:1 was found to be 0.33 mmHg/ml/sec. This is high compared with the normal resistance of the pulmonary valve (0.0333 mmHg/ml/sec), mitral valve (0.0334 mmHg/ml/sec) and aortic valve (0.02 mmHg/ml/sec). The model also predicted that increasing pulmonary artery resistance reduces the work load on the heart.

Despite the simplicity of the model, the results showed good agreement with available clinical and experimental data. This model provides a useful basis for analyzing the hemodynamics of ventricular septal defects.

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