What is the clinical evidence from this study?

Study design: Other. Population: Cardiac wave propagation (computational model). Intervention: Fiber rotation and electrical anisotropy vs. Isotropic model and varying degrees of anisotropy. Primary outcome: Wave propagation speed and scroll wave dynamics.

May 9, 2014Open Access

Electrical Wave Propagation in an Anisotropic Model of the Left Ventricle Based on Analytical Description of Cardiac Architecture

SPSergei F. PravdinUral Federal University HDHans DierckxElectrophysiology LKLeonid B. KatsnelsonInstitute of Immunology and Physiology

Key Result

In a computational model of the human left ventricle, increasing the fiber rotation angle accelerated the spread of electrical excitation and decreased the period of scroll wave rotation.

Structured PICO

Population

Computational modeling study of electrical wave propagation in an anisotropic model of the human left ventricle.

Exposure

Variation of fiber rotation angle and electrical anisotropy (ratio of conductivity coefficients along and across myocardial fibers)

Comparator

Isotropic model (D1=D2) and models with varying degrees of fiber rotation/anisotropy

Outcome

Wave propagation speed, arrival time, and scroll wave dynamics (drift velocity and rotation period)surrogate

Computational modeling shows that myocardial fiber rotation accelerates cardiac electrical activation and modulates scroll wave dynamics, providing insights into mechanisms of ventricular fibrillation.

Limitations

The model does not include the Purkinje conduction system.
The study uses a mono-domain rather than bi-domain representation of cardiac tissue, limiting its application to defibrillation studies.

Abstract

We develop a numerical approach based on our recent analytical model of fiber structure in the left ventricle of the human heart. A special curvilinear coordinate system is proposed to analytically include realistic ventricular shape and myofiber directions. With this anatomical model, electrophysiological simulations can be performed on a rectangular coordinate grid. We apply our method to study the effect of fiber rotation and electrical anisotropy of cardiac tissue (i.e., the ratio of the conductivity coefficients along and across the myocardial fibers) on wave propagation using the ten Tusscher-Panfilov (2006) ionic model for human ventricular cells. We show that fiber rotation increases the speed of cardiac activation and attenuates the effects of anisotropy. Our results show that the fiber rotation in the heart is an important factor underlying cardiac excitation. We also study scroll wave dynamics in our model and show the drift of a scroll wave filament whose velocity depends non-monotonically on the fiber rotation angle; the period of scroll wave rotation decreases with an increase of the fiber rotation angle; an increase in anisotropy may cause the breakup of a scroll wave, similar to the mother rotor mechanism of ventricular fibrillation.

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