Is Ablation to Termination the Best Strategy for Ablation of Persistent Atrial Fibrillation?

Abstract

A lthough effective results are attained with paroxysmal atrial fibrillation (AF) ablation based on pulmonary vein isolation (PVI), catheter ablation of persistent AF remains a challenging task. Current ablation approaches in persistent AF ablation are markedly diverse, and there is a considerable variation in the reported clinical outcomes.1 Moreover, the lack of a distinct procedural end point makes comparison between the studies difficult. Response by Latchamsetty and Oral on p 971Recently, significant advances have been made with the development of novel technologies, such as computational mapping and panoramic noninvasive mapping to map drivers (rotors and focal discharges) during AF. The advent of these newer technologies and strategies for persistent AF ablation further raise the question as to whether AF termination should be the procedural end point, and whether it confers additional long-term clinical benefit.In this article, we review the current evidence on AF termination and long-term clinical outcome, procedural AF termination as a predictor of freedom from recurrent atrial arrhythmias, AF termination rates with various ablation strategies, and potential underlying mechanisms conferring clinical benefit and future directions. AF Termination and Clinical Outcome Search StrategyThe English scientific literature in the PubMed database was searched using the terms catheter ablation, persistent AF, and termination in any region of the PubMed record until October 2014. Studies that described procedural AF termination rates during ablation together with clinical outcomes after ablation for patients with persistent AF or long-standing persistent AF were included. References from the relevant articles were reviewed to identify further related articles. Definition of AF termination included direct conversion to sinus rhythm (SR) and organization to atrial tachycardia (AT) during ablation.

2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation

“…Although termination of AF has been shown by some to be predictive of longer-term outcome, other studies have not confirmed this finding. 399 , 400 , 401 , 515 , 621 , 641 , 642 It is unclear whether acute, intraprocedural termination is a true indication of procedural success, or simply might indicate patients with less persistent AF who are destined to do better regardless of the approach used. A substudy of the STAR AF II trial has suggested this latter point.…”

Hierarchical analysis of electrograms to guide termination of persistent atrial fibrillation

“…In this report, we successfully applied our FS detection algorithm in real time and demonstrated persistent AF termination during FS ablation at the base of the LAA after PV antral ablation. Although AF termination has been associated with improved AF-free survival postablation, 2 this end point is not yet a reproducible benchmark of long-term success. Therefore, we intend to complete 1-year clinical follow-up to assess the efficacy of our adjuvant ablation strategy.…”

“…Ablation strategies beyond pulmonary vein (PV) isolation (PVI) have not been shown to provide incremental benefit in terms of maintaining sinus rhythm 1 . However, there are data suggesting that acute termination of AF during ablation of extra-PV sources could lead to improved freedom from AF recurrence 2 . As such, there is intense interest to better characterize and identify such potential “drivers” of AF, which may be amenable to ablation and improve outcomes.…”

In silico Comparison of Left Atrial Ablation Techniques That Target the Anatomical, Structural, and Electrical Substrates of Atrial Fibrillation

“…For example, PVI ablation alone was sufficient for an acute response -and hence the optimal ablation approach -for 20% of the virtual patient models. Lim et al (2015) reported a higher acute AF termination rate with PVI of 30-60% across multiple clinical trials. This value may be lower in our study because we only studied the ability of the atria to sustain rather than initiate AF; the significant impact of trigger removal on outcome is therefore not captured by our current model.…”

“…We only included 50 patient-specific models which are insufficient to predict optimal ablation pattern for the six approaches simulated. We simulated and predicted acute outcome, which while correlated with, is not equivalent to long term outcome (Lim et al, 2015). We joined ablated regions to their closest region with additional ablation lines to avoid islands of ablated tissue causing re-entry; however, how best to do this requires further investigation.…”