We have refined our existing model for myocardial and ventricular mechanics to include the effects of collagen on the elasticity of the myocardium, non-cylindrical geometry, pathological fiber organization, myocardial blood flow, myocardial oxygen demand, and effects of electrical activation patterns. The model was used in conjunction with ultrasonic kinematic data, gated radionuclide ventriculography, and left heart catheterization data to determine performance parameters. The physiological relationships between phasic coronary arterial and venous pressure and blood flow, aortic input impedance and ventricular dimensions will be determined. A mathematical and physical model of myocardial blood flow will be developed incorporating vessel collapse. Experimental techniques will be developed to measure vascular distensibility in man. RF backscatter from the myocardium will be investigated both experimentally and mathematically with the idea of determining the stress field.
