| Left Ventricular (LV) aneurysm, a complication of myocardial infarction, is a subset of the single largest killer of residents in the United States, coronary heart disease. This thesis combines traditional mechanical testing techniques (biaxial material property testing), with state of the art computer simulations (Finite Element Method (FEM)) to analyze LV aneurysm. Specifically this thesis will show the effect of changing material properties on both the global and regional function of the left ventricle.; To obtain realistic material parameters for LV aneurysm tissue, an ovine model of LV aneurysm was used. Following harvest of the tissue, biaxial material property testing was preformed on the tissue. We found the aneurysm tissue to be stiffer than previously reported by other investigators.; The impact of these new LV aneurysm material properties was examined by creating a realistic finite element model of the left ventricle as a whole. The geometry for this model was obtained using a magnetic resonance imaging (MRI) scan of the ovine LV aneurysm model. The model predicted an increase in cardiac function as measured by the Starling relation, a global decrease in fiber stress, and a global increase in cross-fiber stress. The results have important implications to the structural changes that might be occurring not only in the aneurysm region of the left ventricle, but also in the border zone and remote regions of the heart.; In an attempt to isolate the impact of each material parameter upon cardiac function, a series of simulations was conducted. The stiffness of the aneurysm was modeled in a number of ways. With all of the methods, cardiac function was improved as stiffness was increased. However, each method yielded different results for stress and strain predictions. This has important implications to the cellular response to changing stress and strain patterns following LV aneurysm and highlights the importance of choosing accurate material parameters. |
