Electrocardiographic imaging in the atria

Abstract

The inverse problem of electrocardiography or electrocardiographic imaging (ECGI) is a technique for reconstructing electrical information about cardiac surfaces from noninvasive or non-contact recordings. ECGI has been used to characterize atrial and ventricular arrhythmias. Although it is a technology with years of progress, its development to characterize atrial arrhythmias is challenging. Complications can arise when trying to describe the atrial mechanisms that lead to abnormal propagation patterns, premature or tachycardic beats, and reentrant arrhythmias. This review addresses the various ECGI methodologies, regularization methods, and post-processing techniques used in the atria, as well as the context in which they are used. The current advantages and limitations of ECGI in the fields of research and clinical diagnosis of atrial arrhythmias are outlined. In addition, areas where ECGI efforts should be concentrated to address the associated unsatisfied needs from the atrial perspective are discussed.

Keywords: Atrial arrhythmias; Catheter ablation; Electrocardiographic imaging; Inverse solution; Treatment guidance.

Fig. 1

Summary of topics covered in the review

Fig. 2

Modalities of inverse problem resolutions in the atria. Reconstruction of epicardial potentials or activation times is accomplished through body surface measurements in the first two scenarios; reconstruction of surface potentials is accomplished in the third case through intracavitary potentials

Fig. 3

A Correlation coefficient of ECGI and simulations of 14 different inverse problem methodologies for sinus rhythm (SR) and simple and complex atrial fibrillation (SAF, CAF), extracted from [61]. B Phase singularity of intracardiac and ECGI phase maps and correlation of intracardiac and noninvasive atrial fibrillation sources [71]. C Dominant frequency of intracardiac and ECGI maps and correlation of intracardiac and noninvasive dominant frequencies [41]

Fig. 4

Linearity verification around a PS rotor candidate. Only those PSs with a linear progression of phase in their surrounding should be considered actual reentries [100]

Fig. 5

Comparison of reconstructions (epicardial potentials, dominant frequencies, phases, and phase singularities) between L0 Tikhonov and a new constrained Tikhonov regularization technique that combines noninvasive and invasive recordings, adapted from [82]