First-Time Catheter Ablation for Persistent AFib Not Benefited by Addition of PWI to PVI

Peter M. Kistler, MBBS, PhD

New research does not support the empirical inclusion of posterior wall isolation (PWI) to pulmonary vein isolation (PVI) for ablation of persistent atrial fibrillation (AF).

For patients who had undergone first-time catheter ablation for persistent AF, study data from the CAPLA trial suggest the addition of PWI to PVI alone did not significantly improve freedom from atrial arrhythmia at 12 months, compared with PVI alone.

“In the search for adjunctive strategies to improve ablation outcomes in patients with persistent AF beyond those achieved with PVI alone, the results of this study represent a further disappointment,” wrote study author Peter M. Kistler, MBBS, PhD, Heart Centre at the Alfred Hospital.

AF ablation in PVI is less effective in persistent AF compared with paroxysmal AF, cited Kistler and colleagues. As the left trial posterior wall may contribute to the maintenance of persistent AF, PWI is a common adjunct to PVI. However, successful PWI can be challenging and has not been subjected to randomized comparison.

Individuals in the CAPLA trial were recruited from 11 experienced centers in 3 countries (Australia, Canada, UK). Eligible patients were 18 years or older, had a symptomatic persistent AF refractory to at least 1 antiarrhythmic medication, and were undergoing a first-time ablation procedure for persistent AF. The study population was randomized in a 1:1 ratio to PVI with PWI or PVI alone between July 2018 and March 2021.

Primary study endpoints were identified at the freedom from any documented atrial arrhythmia (AF, atrial tachycardia, or atrial flutter) of more than 30 seconds at minimum of 12-month follow-up after a single ablation procedure without antiarrhythmic medication. Continuation of antiarrhythmic medication beyond 3 months, or a repeat ablation procedure at any time, were considered treatment failures for the primary outcome analysis.

A total of 23 prespecified secondary endpoints included freedom from atrial arrhythmia with/without antiarrhythmic medication after multiple procedures, freedom from symptomatic AF with/without antiarrhythmic medication after multiple procedures, AF burden between study groups at 12 months, procedural outcomes, and complications.

Among the 338 patients (mean age, 65.6 years; 76.9%) enrolled in the study, 330 (97.6%) completed the study. During the time of ablation, 206 patients (60.9%) were in AF/atrial tachycardia/atrial flutter, which included 108 (63.5%) in the PVI with PWI group, and 98 (58.3%) in the PVI-alone group.

Regarding the primary outcome, at 12 months, freedom from recurrent atrial arrhythmia after 1 ablation procedure without the use of antiarrhythmic medication, was present in 89 of 170 patients (52.4%) assigned to PVI with PWI, compared with 90 (53.6%) assigned to PVI alone (between-group difference, –1.2%; hazard ratio [HR], 0.99 [95% CI, 0.73 - 1.36]; P = .98).

Results from the secondary outcomes indicate the mean procedural times (142 for PVI with PWI group vs. 121 minutes for PVI-alone; mean difference, 21 minutes; P <.001) and radiofrequency abolition times (34 minutes vs. 28 minutes; mean difference, 6 minutes; P <.001) were significantly shorter for PVI alone.

With or without antiarrhythmic medication, the data suggest no significant differences between groups with regard to freedom from any atrial arrhythmia after multiple ablation procedures, freedom from atrial flutter/tachycardia after multiple procedures, and freedom from symptomatic atrial arrhythmia after multiple procedures. The adverse event results additionally show there were 6 complications for PVI with PWI and 4 for PVI alone.

“The present study did not support the empirical deployment of PWI for first-time AF ablation,” Kistler added. “However, further studies are needed to identify patient subgroups who may benefit.”

The study, “Effect of Catheter Ablation Using Pulmonary Vein Isolation With vs. Without Posterior Left Atrial Wall Isolation on Atrial Arrhythmia Recurrence in Patients With Persistent Atrial Fibrillation: The CAPLA Randomized Clinical Trial,” was published in JAMA.