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.

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<0.001) and those at first ablation (dashed lines, p<0.001).