Effects of fiber orientation and the anisotropic behavior of the cardiac tissue on the simulated electrocardiogram.

The anisotropic electrical nature of the cardiac tissue, dependent on the fiber orientations and corresponding conductivity tensor components, plays an important role in computational simulations of the electrophysiology of the heart. To date, no accurate technique is utilized to assess how these variations in fiber angles and conductivity change the electrical behavior of the heart. Herein, we make use of six-lead electrocardiograms to demonstrate how this variability affect electrical responses of the heart. To generate an electrocardiogram, consistent with the clinical outputs, the simulation of the Purkinje fibers is also crucial. Moreover, an action potential duration heterogeneity exists among different cells based on their position in the ventricles. In this regard, we simulate a transmural distribution for the action potential duration where the longest repolarization time belongs to the midmyocardial cells. It is demonstrated that variations in fiber angles, from the endocardium to the epicardium, have no significant effect not only on the computational results but also on the clinical response of the electrocardiograms. We also show that different conduction velocities have major effects on the six leads. All together, our results demonstrate that different bounds of fiber angles do not play an important role in electrical cardiac models; however, conduction velocities should be measured and taken into account precisely due to their significant electrophysiological effects. [ABSTRACT FROM AUTHOR]