Ventricular anatomical complexity and gender differences impact predictions from computational models

Abstract

The aim of this work was to analyze the influence of the gender and anatomical details (trabeculations and false tendons) on the electrophysiology of healthy and infarcted myocardium and their relation to the ventricular tachycardia (VT) inducibility. To this end, four anatomically normal, human, biventricular geometries (two male, two female), with identifiable trabeculations, were obtained from high-resolution, ex-vivo MRI and represented by detailed and smoothed geometrical models (with and without the trabeculations). Additionally one model was augmented by a scar. The electrophysiology finite element model (FEM) simulations were carried out, using O’Hara-Rudy human myocyte model, and the comparison of detailed vs smooth, male vs female, as well as normal vs infarcted anatomy was carried out. Finally, the infarcted case was subjected to standard clinical programmed stimulus S1-S4 protocol to identify geometry- and gender-specific VT inducibility. All female hearts presented action potential prolongation and QRS interval lengthening. Smooth geometries showed different QRS pattern and T wave magnitude in comparison to the corresponding trabeculated geometries. A variety of sustained VTs were obtained in the detailed and smoothed male geometries at different pacing locations, which provide evidence of the geometry-dependent differences regarding the prediction of the locations of reentry channels. In the female phenotype, sustained VTs were induced in both detailed and smooth geometries with RV apex pacing, however no consistent reentry channels were identified. Anatomical and physiological cardiac features play an important role defining risk in cardiac disease. These are often excluded from electrophysiological simulations. The assumption that the cardiac endocardium is smooth may inaccurately predict different reentry channel locations in tachycardia inducibility studies.