This article was originally published here

Annu Int Conf IEEE Eng Med Biol Soc. November 2021; 2021: 730-733. doi: 10.1109/EMBC46164.2021.9629911.

Catheter ablation for atrial fibrillation (AF) is one of the most commonly used electrophysiological procedures. Although our understanding of AF mechanisms has made significant progress in the past few years, the results of ablation are still not ideal for many patients, especially those with persistent or long-term AF. One possible reason is that the ablation technique focuses on the anatomy, rather than the patient's functional goal of ablation. The identification of such ablation targets is still challenging. The purpose of this study is to study a new method based on a directed network that allows automatic detection of important arrhythmia mechanisms and is convenient for guiding ablation strategies. These networks are generated by processing unipolar electrograms (EGM) collected by catheters located in different areas of the atrium. The vertex of the network represents the location of the record, and the edge is determined using the cross-covariance time delay estimation method. The algorithm recognizes rotation activity and propagates from one vertex to another, forming a loop. This work is a simulation study that uses a highly detailed computational 3D model of the human atrium, which achieves continuous rotor activation of the atrium. Virtual electrodes are placed on the surface of the endocardium, and the EGM is calculated on each electrode. The propagation of the electric wave front in the atrial myocardium during AF is very complicated, so in order to correctly capture the wave propagation pattern, we divide the EGM into multiple short time frames. Then, a specific network is generated for each of these time frames, and the repeated loops in the continuous network point us to the position of the stable rotor. The respective atrial voltage graph is used as a reference. By detecting the loops between the same 3 nodes in 19 of 58 networks, 10 of which are in a continuous time range, a stable rotor is successfully located.