Initial independent outcomes from focal impulse and rotor modulation ablation for atrial fibrillation: multicenter FIRM registry

Abstract

Introduction: The success of pulmonary vein isolation (PVI) for atrial fibrillation (AF) may be improved if stable AF sources identified by Focal Impulse and Rotor Mapping (FIRM) are also eliminated. The long-term results of this approach are unclear outside the centers where FIRM was developed; thus, we assessed outcomes of FIRM-guided AF ablation in the first cases at 10 experienced centers.

Methods: We prospectively enrolled n = 78 consecutive patients (61 ± 10 years) undergoing FIRM guided ablation for persistent (n = 48), longstanding persistent (n = 7), or paroxysmal (n = 23) AF. AF recordings from both atria with a 64-pole basket catheter were analyzed using a novel mapping system (Rhythm View(TM) ; Topera Inc., CA, USA). Identified rotors/focal sources were ablated, followed by PVI.

Results: Each institution recruited a median of 6 patients, each of whom showed 2.3 ± 0.9 AF rotors/focal sources in diverse locations. 25.3% of all sources were right atrial (RA), and 50.0% of patients had ≥1 RA source. Ablation of all sources required a total of 16.6 ± 11.7 minutes, followed by PVI. On >1 year follow-up with a 3-month blanking period, 1 patient lost to follow-up (median time to 1st recurrence: 245 days, IQR 145-354), single-procedure freedom from AF was 87.5% (patients without prior ablation; 35/40) and 80.5% (all patients; 62/77) and similar for persistent and paroxysmal AF (P = 0.89).

Conclusions: Elimination of patient-specific AF rotors/focal sources produced freedom-from-AF of ≈80% at 1 year at centers new to FIRM. FIRM-guided ablation has a rapid learning curve, yielding similar results to original FIRM reports in each center's first cases.

Keywords: FIRM-guided ablation; atrial fibrillation; catheter ablation; focal impulse; rotors.

© 2014 Wiley Periodicals, Inc.

Figures

Figure 1

(A) Workflow for FIRM-guided ablation of AF. (B) Typical basket placement and results from FIRM-guided ablation. Basket placed in left atrium, with resulting FIRM map showing AF rotor at roof with surrounding spiral arms disorganizing and fusing with the fibrillatory milieu (blocked arrows) and rotor precession within a limited area on successive cycles (not shown).

Figure 2

AF source locations in both atria for patients with (A) paroxysmal and (B) persistent AF.

Figure 3

Freedom from atrial fibrillation after single (index) FIRM + PVI procedure for all cases (green) and patients at their first ablation (blue).

Figure 4

Freedom from all atrial arrhythmias (atrial fibrillation and atrial tachycardia) after a single (index) FIRM + PVI procedure for all cases (green) and patients at their first ablation (blue).

Figure 5

Freedom from atrial fibrillation after a single index FIRM + PVI procedure for patients with paroxysmal AF in blue and persistent AF (including longstanding persistent AF) in green.