Focal Impulse and Rotor Modulation Ablation vs. Pulmonary Vein isolation for the treatment of paroxysmal Atrial Fibrillation: results from the FIRMAP AF study

Aims: Pulmonary vein isolation (PVI) is the gold standard for atrial fibrillation (AF) ablation. Recently, catheter ablation targeting rotors or focal sources has been developed for treatment of AF. This study sought to compare the safety and effectiveness of Focal Impulse and Rotor Modulation (FIRM)-guided ablation as the sole ablative strategy with PVI in patients with paroxysmal AF.

Methods and results: We conducted a multicentre, randomized trial to determine whether FIRM-guided radiofrequency ablation without PVI (FIRM group) was non-inferior to PVI (PVI group) for treatment of paroxysmal AF. The two primary efficacy end points were (i) acute success defined as elimination of AF rotors (FIRM group) or isolation of all pulmonary veins (PVI group) and (ii) long-term success defined as single-procedure freedom from AF/atrial tachycardia (AT) recurrence 12 months after ablation. The study was closed early by the sponsor. At the time of study closure, any pending follow-up visits were waived. A total of 51 patients (mean age 63 ± 10.6 years, 57% male) were enrolled. All PVs were successfully isolated in the PVI group and all rotors were successfully eliminated in the FIRM group. Single-procedure effectiveness was 31.3% (5/16) in the FIRM group and 80% (8/10) in the PVI group at 12 months. Three vascular access complications occurred in the FIRM group.

Conclusion: These partial study effectiveness results reinforce the importance of PVI in paroxysmal AF patients and indicate that FIRM-guided ablation alone (without PVI) is not an effective strategy for treatment of paroxysmal AF in most patients.