Effect of aspect ratios on stress and strain of a multilayer model for the left ventricle

Abstract

A basic understanding of the heart behavior assists in the accurate diagnosis of heart disease, which is the leading cause of death in Thailand. The mechanical behaviors of the heart can be ideally explained by strain and stress. This work numerically and analytically described three layers of the heart wall in a computational model, while previous studies only considered the myocardium, which is a muscular layer. Moreover, the shape of the left ventricle (LV) varies among individuals. The influence of the LV shape, as assumed to be a truncated ellipse, was considered by varying the short-to-long-axis and wall-to-cavity-volume ratios to investigate strain and stress in the radial, circumferential and longitudinal directions during a passive filling with blood using a continuum approach. For verification, the model was compared to other research work by defining the wall-to-cavity-volume and short-to-long-axis ratios as well by as fiber distribution. The results showed that an increasing short-to-long-axis ratio obviously resulted in decreased overall strains and stresses. Whereas, increasing the wall-to-cavity-volume ratio slightly decreased radial contraction as well as circumferential and longitudinal expansion. The fiber strains of the linear fiber distribution corresponded well with previous work at a high longitudinal curvature.