Simulation of biatrial conduction via different pathways during sinus rhythm with a detailed human atrial model

Abstract

In order to better understand biatrial conduction, investigate various conduction pathways, and compare the differences between isotropic and anisotropic conductions in human atria, we present a simulation study of biatrial conduction with known/assumed conduction pathways using a recently developed human atrial model. In addition to known pathways: (1) Bachmann's bundle (BB), (2) limbus of fossa ovalis (LFO), and (3) coronary sinus (CS), we also hypothesize that there exist two fast conduction bundles that connect the crista terminalis (CT), LFO, and CS. Our simulation demonstrates that use of these fast conduction bundles results in a conduction pattern consistent with experimental data. The comparison of isotropic and anisotropoic conductions in the BB case showed that the atrial working muscles had small effect on conduction time and conduction speed, although the conductivities assigned in anisotropic conduction were two to four times higher than the isotropic conduction. In conclusion, we suggest that the hypothesized intercaval bundles play a significant role in the biatrial conduction and that myofiber orientation has larger effects on the conduction system than the atrial working muscles. This study presents readers with new insights into human atrial conduction.

A Surface-Based Electrophysiology Model Relying on Asymptotic Analysis and Motivated by Cardiac Atria Modeling

“…The depolarization of the right and left atrium are complete at 101.8 ms and 109.6 ms, respectively. This is in good adequacy with the timings found in [6], namely, 99.3 ms and 108.2 ms, respectively, while [9] gives 115.0 ms for the left atrium, and [4] 119.0 ms.…”

“…The wave has encircled the mouth of the left atrial appendage at 72.8 ms. By t = 80 ms, the only part that remains unaffected by the wave in the right atrium is the isthmus, because of the reduced conductivity there. In the left atrium, at t = 90 ms we can see three separate wavefronts, also obtained in [6,4]. The depolarization of the left atrial appendage is complete at 95.8 ms. At 100 ms, only a small part of the left atrium in the shape of a parallelepiped is still inactive.…”

Surface-Based Electrophysiology Modeling and Assessment of Physiological Simulations in Atria

“…Activation is initiated at the sinus node with a stimulus of 2 ms in duration and sufficient strength to cause the initiation of a propagating wavefront. We compare our results to several 3D modeling studies [9,6,4].…”

An Image-Based Model of the Whole Human Heart with Detailed Anatomical Structure and Fiber Orientation

“…The time step was 0.01 ms, the anisotropy of the atrial working muscles was set as 1.3 : 1 [66], the conduction system was set as 9 : 1 [31], and the ventricular working muscles were set as 2 : 1 [55, 71]. …”