Ablation of rotor and focal sources reduces late recurrence of atrial fibrillation compared with trigger ablation alone: extended follow-up of the CONFIRM trial (Conventional Ablation for Atrial Fibrillation With or Without Focal Impulse and Rotor Modulation)

Abstract

Objectives: The aim of this study was to determine if ablation that targets patient-specific atrial fibrillation (AF)-sustaining substrates (rotors or focal sources) is more durable than trigger ablation alone at preventing late AF recurrence.

Background: Late recurrence substantially limits the efficacy of pulmonary vein isolation for AF and is associated with pulmonary vein reconnection and the emergence of new triggers.

Methods: Three-year follow-up was performed of the CONFIRM (Conventional Ablation for Atrial Fibrillation With or Without Focal Impulse and Rotor Modulation) trial, in which 92 consecutive patients with AF (70.7% persistent) underwent novel computational mapping. Ablation comprised source (focal impulse and rotor modulation [FIRM]) and then conventional ablation in 27 patients (FIRM guided) and conventional ablation alone in 65 patients (FIRM blinded). Patients were followed with implanted electrocardiographic monitors when possible (85.2% of FIRM-guided patients, 23.1% of FIRM-blinded patients).

Results: FIRM mapping revealed a median of 2 (interquartile range: 1 to 2) rotors or focal sources in 97.7% of patients during AF. During a median follow-up period of 890 days (interquartile range: 224 to 1,563 days), compared to FIRM-blinded therapy, patients receiving FIRM-guided ablation maintained higher freedom from AF after 1.2 ± 0.4 procedures (median 1; interquartile range: 1 to 1) (77.8% vs. 38.5%, p = 0.001) and a single procedure (p < 0.001) and higher freedom from all atrial arrhythmias (p = 0.003). Freedom from AF was higher when ablation directly or coincidentally passed through sources than when it missed sources (p < 0.001).

Conclusions: FIRM-guided ablation is more durable than conventional trigger-based ablation in preventing 3-year AF recurrence. Future studies should investigate how ablation of patient-specific AF-sustaining rotors and focal sources alters the natural history of arrhythmia recurrence. (The Dynamics of Human Atrial Fibrillation; NCT01008722).

Keywords: FIRM; ablation; atrial fibrillation; clinical trial; electrical rotors.

Conflict of interest statement

Disclosures: Clopton report no conflicts.

Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1. Patient Tailored Mapping. (A) Persistent Atrial Fibrillation Despite Extensive WACA and Roof line ablation

FIRM mapping proceeded as shown fluoroscopically, using bi-atrial baskets, coronary sinus and ablation catheters, an implantable loop recorder and an esophageal temperature probe; (B) Detection of Right Atrial AF rotor, where FIRM eliminated AF with no other ablation; (C) At 852 days, Incessant Atrial Tachycardia Recurred, and was ablated at original roof line site. RA1,2=right atrial recordings; post LA=posterior left atrial recordings, CS =coronary sinus recordings; Abl=ablation catheter recordings.

Figure 2. Freedom from the Primary End Point (atrial fibrillation)

Freedom from the Primary End Point (atrial fibrillation) for FIRM-guided ablation (blue) and conventional ablation (red; p=0.003).

Figure 3. Freedom from the Secondary End Point (all Atrial Arrhythmias)

Freedom from the Secondary End Point (all Atrial Arrhythmias) for FIRM-guided ablation (blue) and conventional ablation (red; p=0.01).

Figure 4. Single-Procedure freedom from the Primary End Point (atrial fibrillation) for FIRM-guided ablation (blue) and conventional ablation (red)

Data shows all cases (solid lines, p=0.002) and those undergoing their first ablation (dashed lines, p=0.002).

Figure 5. Cumulative freedom from the Primary End Point (atrial fibrillation) in patients based on whether the procedure directly or coincidentally ablated rotors or focal sources (red) or missed rotors/sources (blue)

Data shows all cases (solid lines, p