Theoretical analysis of the magnetocardiographic pattern for reentry wave propagation in a three-dimensional human heart model

Abstract

We present a computational study of reentry wave propagation using electrophysiological models of human cardiac cells and the associated magnetic field map of a human heart. We examined the details of magnetic field variation and related physiological parameters for reentry waves in two-dimensional (2-D) human atrial tissue and a three-dimensional (3-D) human ventricle model. A 3-D mesh system representing the human ventricle was reconstructed from the surface geometry of a human heart. We used existing human cardiac cell models to simulate action potential (AP) propagation in atrial tissue and 3-D ventricular geometry, and a finite element method and the Galerkin approximation to discretize the 3-D domain spatially. The reentry wave was generated using an S1-S2 protocol. The calculations of the magnetic field pattern assumed a horizontally layered conductor for reentry wave propagation in the 3-D ventricle. We also compared the AP and magnetocardiograph (MCG) magnitudes during reentry wave propagation to those during normal wave propagation. The temporal changes in the reentry wave motion and magnetic field map patterns were also analyzed using two well-known MCG parameters: the current dipole direction and strength. The current vector in a reentry wave forms a rotating spiral. We delineated the magnetic field using the changes in the vector angle during a reentry wave, demonstrating that the MCG pattern can be helpful for theoretical analysis of reentry waves.

Toward cardiac electrophysiological mapping based on micro-Tesla NMR: a novel modality for localizing the cardiac reentry

“…MCG or MEG is not sensitive to the normal component of myocardial current but only sensitive to the tangential current to the thorax surface. 6 Presumably, the local current strength was underestimated because MCG omitted the normal component of myocardial currents. This factor will give a stronger signal in a practical measurement as the normal component of myocardial currents can generate the tipping magnetic field, too.…”

“…6,16 First, I simulated heart magnetic fields generated from a cyclic excitation of transmembrane potential on the myocardial surface. 16 In biomagnetism, they generally utilize equivalent current dipoles (ECD) as its sources.…”

“…Emerging studies dealing with electrophysiology (EP) in cardiology, [1][2][3][4][5] biology 6,7 and nonlinear dynamics 8,9 are reporting theoretical and experimental evidences that most of pathological cardiac conduction disorders originate from generation of reentrant sources either in ventricles or in atria. Especially, the surgical treatments for atrial fibrillation (AF) and atrial flutter are mainly based on blocking all the possible abnormal reentrant circuits on the myocardium.…”

“…Three-dimensional tissue excitation cannot be investigated by such two-dimensional measurements. 6 Non-invasively, body surface potential mapping or magnetocardiography (MCG) 16 can be applied, but the ill-posedness in inverse problems limits the accuracy of the source localization, especially for deep sources.…”

The Relationship among Complex Fractionated Electrograms, Wavebreak, Phase Singularity, and Local Dominant Frequency in Fibrillation Wave-Dynamics: a Modeling Comparison Study

“…7.13 (MathWorks Co., Natick, MA, USA). The source code of the cell model was from the CellML version and already implemented in our previous computational studies (6-8). The solution algorithm for the bidomain method was from Ashihara et al (9).…”