Microstructural remodelling and mechanics of hypertensive heart disease

Abstract

Changes in heart geometry and microstructural remodelling of myocardium are pathological processes that occur in heart failure (HF). The combination of effects often leads to compromised mechanical function of the left ventricle (LV). We have developed an image-driven constitutive modelling framework, which integrates subject-specific geometric data and microstructural organisation of the myocardial tissue, in order to investigate the mechanisms of heart function in health and disease. In this study, we investigated the effect of myocardial microstructural remodelling on passive mechanical function of the LV during the progression of hypertension-induced HF. We constructed finite element models of the LV using geometric data derived from in vivo magnetic resonance images of healthy and failing rat hearts at both 14-months and 24-months of age. By incorporating subject-specific LV geometries and parameters that directly reflect the tissue microstructure, we demonstrated that a single set of fitted constitutive parameters could reproduce the observed LV chamber compliance curves in all four cases (healthy and diseased hearts at 14-months and 24-months). This study highlights the important role that remodelling of myocardial microstructure plays in the mechanics of the failing heart.