Mechanics of the ischemic left ventricle during the cardiac cycle

The mechanics of the ischemic left ventricle (LV) is investigated using a finite element model. The model considers the varying muscle fiber orientation across the LV wall, the anisotropy of the passive myocardial tissue, the dependency of active stress on time, strain and strain rate, the activation sequence of the LV wall and the aortic afterload. The results of the simulation of the mechanics of the ischemic LV show that the global deformation pattern is asymmetric with respect to the ischemic region. In the ischemic region, the LV wall becomes relatively thin and fibers are stretched during the ejection phase. Muscle fiber shortening and active muscle fiber stress in the borderzone of the ischemic region are found to depend strongly on the relation between the orientation of the muscle fibers in the borderzone and the orientation of the borderzone with respect to the ischemic region. Epicardial deformation as calculated with the model agrees quite well with experimental data.