Assessment of the Variability in the QRS Complex due to the Heterogeneity in Conduction Velocity in the Ventricles of the Heart: In-Silico Study

Personalized mathematical models of the heart in recent years have become a useful tool for studying the progress of various types of cardiac diseases. In many studies the researchers use the assumption that the local conduction velocity is homogeneous in different regions of the heart.This article is devoted to the analysis of the effect of conduction velocity heterogeneity in different regions of the heart on the QRS complex. To build an anatomical model of the heart, lungs and torso, we used computer tomography data. Then, on the constructed grid, five regions were selected: the endocardium of the right ventricle, the endocardium of the left ventricle, the septum wall, the left ventricle and the right ventricle (middle layer and epicardium). We randomly generated 200 sets of conductivity parameters in these segments. Then we solved the ECG problem using a model based on the eikonal equation, with three different stimulation protocols: normal activation, LBBB activation, and activation from CRT leads.Using the simulation results, we show that heterogeneity can lead to completely different QRS patterns in CRT cases, which indicates the importance of cardiac heterogeneity in ECG modeling. At the same time, we show that for the case of normal and LBBB activation, the QRS variability is small, and the heterogeneity can be neglected.