Elsevier

Heart Rhythm

Volume 17, Issue 10, October 2020, Pages 1740-1744
Heart Rhythm

Clinical
Atrial Fibrillation
Durability of posterior wall isolation after catheter ablation among patients with recurrent atrial fibrillation

https://doi.org/10.1016/j.hrthm.2020.05.005Get rights and content

Background

Electrical posterior wall isolation (PWI) is increasingly being used for the treatment of patients with atrial fibrillation (AF). Few data exist on the durability of PWI using current technology.

Objective

The purpose of this study was to characterize the frequency and location of posterior wall reconnection at the time of repeat catheter ablation for AF.

Methods

We performed a single-center retrospective cohort study of 50 patients undergoing repeat AF ablation after previous PWI. Durability of PWI was assessed at the time of repeat ablation based on posterior wall entrance and exit block. Sites of posterior wall reconnection were characterized based on review of recorded electrical signals and electroanatomic maps.

Results

At the time of repeat ablation, mean age was 67 ± 10 years, 31 of 50 patients had persistent AF, and mean CHA2DS2-VASc score was 3.0 ± 1.8. Of the 50 patients, 30 had durable PWI at repeat ablation, 1.4 ± 1.6 years after the index procedure. Patients with posterior wall reconnection required repeat ablation earlier (0.9 ± 0.6 years vs1.8 ± 1.9 years from index PWI; P = .048) and were more likely to have atypical atrial flutter (55% vs 27%; P = .043). Among patients with posterior wall reconnection, the roof was the most common site of reconnection (14/20), and 12 patients had multiple regions of reconnection noted.

Conclusion

Posterior wall reconnection is noted in 40% of patients undergoing repeat ablation after an index PWI. The roof of the left atrium is the most common site of posterior wall reconnection.

Introduction

Catheter ablation of atrial fibrillation (AF) is an effective strategy for treatment of paroxysmal and persistent AF. Pulmonary vein isolation (PVI) is the foundation of all AF ablation strategies, although recurrence of AF after PVI alone remains frequent, particularly with persistent AF.1 Nonpulmonary vein triggers arising from the posterior wall of the left atrium (LA), which may be particularly prone to conduction delay due to fibrosis and complex tissue architecture, frequently initiate AF.2,3 Thus, posterior wall isolation (PWI) is of theoretical benefit to prevent recurrent AF in addition to PVI. However, results regarding the efficacy of routine PWI are conflicting, as is the evidence that it may impair LA function or predispose to the development of LA flutter.4, 5, 6

Beyond determining the ideal patient population that would benefit from PWI, there are technical challenges in performing successful PWI. The posterior wall is a thin-walled structure in immediate proximity to the esophagus, and aggressive lesion creation may increase the risk of atrioesophageal fistula formation. Limited in part by this concern as well as by frequent direct epicardial connections, PWI can be challenging with endocardial ablation, and epicardial connections may be overlooked or only transiently interrupted.7,8 Incomplete PWI, either at the time of the procedure or with subsequent reconnection as edema resolves, may provide the substrate for atypical LA flutters.8

Reconnection across ablation lesions from PVI is a common reason for AF recurrence after ablation, and reconnection after PWI may also be a cause of recurrence or proarrhythmia.9,10 Given the growing interest in PWI as an ablation strategy for AF, we aimed to investigate its durability among patients with recurrent AF after a single index PVI and PWI, who were undergoing redo ablation.

Section snippets

Methods

We performed a retrospective cohort study at the Hospital of the University of Pennsylvania. All patients provided written informed consent for both their ablation procedure and use of their anonymized medical information for research. This research was approved by the Institutional Review Board. All patients referred to the Hospital of the University of Pennsylvania for catheter ablation of AF between 2009 and 2018 were eligible for inclusion. Reports from ablation procedures were screened to

Results

From among 8944 catheter ablation procedures for AF between 2009 and 2018, we identified 50 patients who underwent repeat catheter ablation for AF after a single index PVI and PWI at our institution (Table 1). At the time of the repeat ablation, patient age was 67 ± 10 years old, 19 (38%) had paroxysmal AF, and mean CHA2DS2-VASc score was 3.0 ± 1.8. All patients were taking oral anticoagulation at the time of ablation. The index PVI and PWI had been performed a mean of 1.4 ± 1.6 years before

Discussion

Although the role of electrical isolation of the posterior wall of the LA and the optimal patient population have not yet been definitively established, PWI is increasingly used to treat medically refractory AF. The most common technique for PWI is the creation of roof and floor lines connecting bilateral isolated superior and inferior pulmonary veins, respectively. Alternative strategies to achieve PWI have been suggested, and the scattered technique is increasingly advocated. With this

Conclusion

Posterior wall reconnection is present in 2 of every 5 patients at the time of redo ablation after previous PWI. The roof of the LA is the most common site of posterior wall reconnection, although multiple areas of connection, including epicardial connections, can be observed. It is critical not only that the role of PWI in patients with AF be clarified but also that the durability of isolation and significance of posterior wall reconnection be further evaluated.

References (14)

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    Endocardial posterior wall isolation is not a routine procedure and may pose additional safety risks, which should be weighed against mixed clinical outcomes reported in the clinical literature.16 Posterior wall reconnection rates have been reported to be approximately 40% after endocardial posterior wall isolation with RF,17,18 and endocardial cryoballoon posterior wall isolation often requires adjunctive RF for completion.19 A recent retrospective observational study reported a propensity score-matched comparison of Catheter Ablation versus Hybrid Convergent ablation for LSPAF, with mean duration of AF from 2.5 to 3 years.20

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Dr Nazarian is a consultant to Siemens, CardioSolv, and Circle Software; has given lectures for Circle Software; and has been a principal investigator for research funding to the University of Pennsylvania from Biosense Webster, Siemens, Imricor, and the National Institutes of Health. Dr Callans is a consultant to Biosense Webster and Abbott. All other authors have reported that they have no conflicts relevant to the contents of this paper to disclose.

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