Mechanics of the septal wall may be affected by the presence of fibrotic infarct in the free wall at end-systole

The relationship between infarct mechanics and ventricular function of the septal wall in the presence of fibrotic infarct in the free wall remains poorly understood. This study compares the mechanics of the septal wall in the healthy and fibrotic infarcted rat heart models during active ejection. To simulate active contraction, three dimensional constitutive Fung model was implemented in Abaqus® commercial software. The endocardial pressures of LV and RV were applied such that the required end-systolic volumes were obtained. To simulate active contraction in the bi-ventricular rat heart model, the pressures of 14.6 kPa and 2.92 kPa were applied on the left ventricle and right ventricle chambers. It was observed in the presence of infarct in the free wall, the stress in the septal wall decreased when compared to the healthy heart. The increase in strain in the septal wall has serious practical implications in global and regional functioning of the heart.