Outcomes were poor among patients with atrial fibrillation who underwent rotor-only ablation, according to the results from the OASIS (Outcome of Different Ablation Strategies in Persistent and Long-Standing Persistent Atrial Fibrillation) trial.

The results, published in the Journal of the American College of Cardiology, also showed that pulmonary vein antrum isolation (PVAI) with rotor ablation had longer procedure times and lower efficacy than PVAI with posterior wall and non-PV trigger-ablation.

Sanghamitra Mohanty, MD, from the Department of Electrophysiology at the Texas Cardiac Arrhythmia Institute, St. David’s Medical Center in Austin, and colleagues conducted the OASIS trial, which sought to compare the efficacy of focal impulse and rotator modulation (FIRM) with or without PVAI vs PVAI with non-PV ablation.


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A total of 113 patients with nonparoxysmal atrial fibrillation undergoing first ablation were included in the study. Twenty-nine patients were randomly assigned to receive FIRM only (group 1), 42 patients to FIRM with PVAI (group 2), and 42 patients to PVAI with posterior wall and non-PV trigger ablation (group 3).

The primary end point was freedom from atrial tachycardia or atrial fibrillation, and the secondary end point was acute procedural success, which was defined as atrial fibrillation termination, ≥10% slowing or organization into atrial tachycardia.

“Our main findings were the following: acute procedural success after targeting the FIRM-identified rotors was achieved in a small number of patients—41% and 26% in group 1 and 2, respectively; rotor-only ablation had very poor outcome in terms of arrhythmia recurrence for which that arm was terminated prematurely; and PVAI plus rotor ablation had significantly longer procedure time and lower efficacy than PVAI + PW [posterior wall] + non-PV trigger ablation,” the authors wrote.

They also found that the procedure time was significantly shorter among patients in group 3 compared with those in groups 1 and 2 (P<.001). Acute success after rotor-only ablation was achieved in 41% of patients in group 1 and 26% of patients in group 2.

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After a follow-up period of 12 ± 7 months, only 14% of patients in group 1 were free of atrial fibrillation and atrial tachycardia without antiarrhythmic drugs. After the same time period, 52.4% of patients in group 2 achieved the primary end point, and 76% of patients in group 3 achieved the primary end point (log-rank P<.0001). Overall, patients in group 3 experienced higher success rates compared with group 1 (P<.001) and group 2 (P=.02).

“Further studies are needed to define systematic approaches for identification and ablation of arrhythmogenic loci in patients with nonparoxysmal atrial fibrillation and to compare the efficacy and safety of alternative strategies in adequately powered randomized trials,” the authors noted.

Reference

Mohanty S, Gianni C, Mohanty P, et al. Impact of rotor ablation in nonparoxysmal atrial fibrillation patients: results from the randomized OASIS trial. J Am Coll Cardiol. 2016;68(3):274-282. doi: 10.1016/j.jacc.2016.04.015.