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Front. Physiol. | doi: 10.3389/fphys.2018.01251

A computational framework to benchmark basket catheter guided ablation in atrial fibrillation

  • 1Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, Università degli Studi di Bologna, Italy
  • 2Institute of Biomedical Engineering, Karlsruher Institut für Technologie (KIT), Germany

Catheter ablation is a curative therapeutic approach for atrial fibrillation (AF). Ablation of rotational sources based on basket catheter measurements has been proposed as a promising approach in patients with persistent AF to complement pulmonary vein isolation. However, clinically reported success rates are equivocal calling for a mechanistic investigation under controlled conditions. We present a computational framework to benchmark ablation strategies considering the whole cycle from excitation propagation to electrogram acquisition and processing to virtual therapy. Fibrillation was induced in a patient-specific 3D volumetric model of the left atrium, which was homogeneously remodelled to sustain reentry. The resulting extracellular potential field was sampled using models of grid catheters as well as realistically deformed basket catheters considering the specific atrial anatomy. Virtual electrograms were processed to compute phase singularity density maps to target rotor tips with up to three circular ablations. Stable rotors were successfully induced in different regions of the homogeneously remodelled atrium showing that rotors are not constrained to unique anatomical structures or locations. Phase singularity density maps correctly identified and located the rotors (deviation < 10 mm) based on catheter recordings only for sufficient resolution (inter-electrode distance = 3 mm) and proximity to the wall (< 10 mm). Targeting rotor sites with ablation did not stop reentries in the homogeneously remodelled atria independent from lesion size (1-7 mm radius), from linearly connecting lesions with anatomical obstacles, and from the number of rotors targeted sequentially (up to 3). Our results show that phase maps derived from intracardiac electrograms can be a powerful tool to map atrial activation patterns, yet they can also be misleading due to inaccurate localization of rotor tips depending on electrode resolution and distance to the wall. This should be considered to avoid ablating regions that are in fact free of rotor sources of AF. In our experience, ablation of rotor sites was not successful to stop fibrillation. Our comprehensive simulation framework provides the means to holistically benchmark ablation strategies in silico under consideration of all steps involved in electrogram-based therapy and, in future, could be used to study more heterogeneously remodelled disease states as well.

Keywords: Atrial Fibrillation, ablation, Basket catheter, Computational modelling, rotor

Received: 31 May 2018; Accepted: 20 Aug 2018.

Edited by:

Jichao Zhao, University of Auckland, New Zealand

Reviewed by:

Sanjay R. Kharche, University of Western Ontario, Canada
Rheeda Ali, Johns Hopkins University, United States  

Copyright: © 2018 Alessandrini, Valinoti, Unger, Oesterlein, Doessel, Corsi, Loewe and Severi. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: PhD. Axel Loewe, Karlsruher Institut für Technologie (KIT), Institute of Biomedical Engineering, Karlsruhe, Germany, axel.loewe@kit.edu