Focal impulse and rotor modulation as a stand-alone procedure for the treatment of paroxysmal atrial fibrillation: A within-patient controlled study with implanted cardiac monitoring

Background: Focal impulse and rotor modulation (FIRM) has been proposed as a novel approach for the treatment of atrial fibrillation (AF).

Objective: This study aimed to investigate the efficacy of FIRM as a stand-alone procedure for the treatment of paroxysmal AF.

Methods: A total of 27 patients with paroxysmal AF underwent sequential biatrial computational mapping. Sites with repetitive centrifugal or spiral reentry-like activity were considered to be AF-sustaining sources and targeted by irrigated radiofrequency (RF) ablation. All patients were seen in the outpatient clinic after 1, 3, and 6 months and thereafter every 6 months. Cardiac monitors were implanted 3 months before ablation in 17 patients (63%).

Results: Repetitive activity interpreted as sustained AF sources was found in all patients, with an average of 3.0 ± 1.1 sources located in the left atrium and 0.6 ± 0.6 sources in the right atrium. The majority of sources were rotors (95%). The total source-ablation radiofrequency time was 20.0 ± 9.0 minutes. At 15.2 ± 3.9 months of follow-up, the prespecified end point of <1% AF burden (outside a 3-month blanking period) was achieved in 2 of the 17 continuously monitored patients (12%). Of all the 27 patients who underwent FIRM, AF episodes of ≥30 minutes were recorded in 23 (85%), while AF episodes ≥60 minutes were recorded in 21 patients (78%).

Conclusion: This study suggest that biatrial ablation of localized patient-specific sources alone, as detected by this method, is not sufficient to reduce paroxysmal AF burden in the majority of patients.