Use of the ventricular propagated excitation model in the magnetocardiographic inverse problem for reconstruction of electrophysiological properties

Abstract

A novel magnetocardiographic inverse method for reconstructing the action potential amplitude (APA) and the activation time (AT) on the ventricular myocardium is proposed. This method is based on the propagated excitation model, in which the excitation is propagated through the ventricle with nonuniform height of action potential. Assumption of stepwise waveform on the transmembrane potential was introduced in the model. Spatial gradient of transmembrane potential, which is defined by APA and AT distributed in the ventricular wall, is used for the computation of a current source distribution. Based on this source model, the distributions of APA and AT are inversely reconstructed from the QRS interval of magnetocardiogram (MCG) utilizing a maximum a posteriori approach. The proposed reconstruction method was tested through computer simulations. Stability of the methods with respect to measurement noise was demonstrated. When reference APA was provided as a uniform distribution, root-mean-square errors of estimated APA were below 10 mV for MCG signal-to-noise ratios greater than, or equal to, 20 dB. Low-amplitude regions located at several sites in reference APA distributions were correctly reproduced in reconstructed APA distributions. The goal of our study is to develop a method for detecting myocardial ischemia through the depression of reconstructed APA distributions.

Noninvasive three-dimensional electrocardiographic imaging of ventricular activation sequence

“…We have proposed a 3-D electrocardiographic imaging technique (3-DEIT), based on a novel imaging technique utilizing body surface potential maps (BSPMs) in which a 3-D electrophysiological heart model is incorporated, that can noninvasively localize sites of origin of myocardial activation (14,20) and image ventricular activation sequence (13,16), distributions of transmembrane potentials (15), and infarction (21). Work by our group (13-16, 20, 21) and others (28,38) in computer simulations suggested the merits of the 3-DEIT approach in imaging and localizing cardiac electrical activity within the 3-D volume of myocardium. Although promising results have been obtained via computer simulation, there have been no in vivo experimental validation studies of the 3-DEIT approach.…”

Three-Dimensional Cardiac Electrical Imaging From Intracavity Recordings

“…In the past few decades, major efforts have been made to estimate epicardial potentials [21], [22], [25] and heart surface activation sequence [26]- [28]. Recent efforts have been made to image the 3-D cardiac electrical activities from the BSPMs [8]- [10], [17]- [20], [29], [30], and from MCG [31]. The present study, to our knowledge, represents the first effort in localizing and imaging cardiac electrical activity within the 3-D volume of the heart from intracavity electrical signals.…”

Modeling of realistic heart electrical excitation based on DTI scans and modi ed reaction diffusion equation

“…Modeling of the heart's electrical excitation (reaction part of the monodomain RDE) is presented on either the cellular scale [14,18,19] or for the whole tissue [10,11,15,33,34]. Some qualitative models have also been developed [20,35] [40], and represents the excitation part of the monodomain RDE with two variables representing the depolarization and the repolarization of the cell membrane.…”