Editorial
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Cardiol. Mar 26, 2015; 7(3): 111-118
Published online Mar 26, 2015. doi: 10.4330/wjc.v7.i3.111
Catheter ablation of persistent atrial fibrillation: The importance of substrate modification
Konstantinos P Letsas, Michael Efremidis, Nikolaos P Sgouros, Konstantinos Vlachos, Dimitrios Asvestas, Antonios Sideris
Konstantinos P Letsas, Michael Efremidis, Nikolaos P Sgouros, Konstantinos Vlachos, Dimitrios Asvestas, Antonios Sideris, Second Department of Cardiology, Laboratory of Cardiac Electrophysiology, Evangelismos General Hospital of Athens, 10676 Athens, Greece
Author contributions: Efremidis M and Sgouros NP performed research; Letsas KP and Vlachos K performed research and drafted article; Asvestas D and Sideris A contributed to the critical revision of article.
Conflict-of-interest: None to declare.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Konstantinos P Letsas, MD, FESC, Second Department of Cardiology, Laboratory of Cardiac Electrophysiology, Evangelismos General Hospital of Athens, Ipsilantou 45-47, 10676 Athens, Greece. k.letsas@mail.gr
Telephone: +30-213-2041467 Fax: +30-213-2041344
Received: October 25, 2014
Peer-review started: October 26, 2014
First decision: November 27, 2014
Revised: December 26, 2014
Accepted: January 18, 2015
Article in press: January 20, 2015
Published online: March 26, 2015
Processing time: 138 Days and 24 Hours
Abstract

Accumulating data have shown that elimination of atrial fibrillation (AF) sources should be the goal in persistent AF ablation. Pulmonary vein isolation, linear lesions and complex fractionated atrial electrograms (CFAEs) ablation have shown limited efficacy in patients with persistent AF. A combined approach using voltage, CFAEs and dominant frequency (DF) mapping may be helpful for the identification of AF sources and subsequent focal substrate modification. The fibrillatory activity is maintained by intramural reentry centered on fibrotic patches. Voltage mapping may assist in the identification of fibrotic areas. Stable rotors display the higher DF and possibly drive AF. Furthermore, the single rotor is usually consistent with organized AF electrograms without fractionation. It is therefore quite possible that rotors are located at relatively “healthy islands” within the patchy fibrosis. This is supported by the fact that high DF sites have been negatively correlated to the amount of fibrosis. CFAEs are located in areas adjacent to high DF. In conclusion, patchy fibrotic areas displaying the maximum DF along with high organization index and the lower fractionation index are potential targets of ablation. Prospective studies are required to validate the efficacy of substrate modification in left atrial ablation outcomes.

Keywords: Ablation; Atrial fibrillation; Persistent; Substrate; Dominant frequency

Core tip: A combined approach using voltage, complex fractionated atrial electrograms and dominant frequency mapping may be helpful for the identification of atrial fibrillation sources, and therefore for sufficient substrate modification in patients with persistent atrial fibrillation undergoing left atrial ablation.