Randomized evaluation of redo ablation procedures of atrial fibrillation with focal impulse and rotor modulation-guided procedures: the REDO-FIRM study.

Aims: REDO-FIRM evaluated safety and effectiveness of conventional vs. focal impulse and rotor modulation (FIRM)-guided ablation of recurrent persistent or paroxysmal atrial fibrillation (AF) after an initial AF ablation procedure.
Methods and Results: This prospective, multicentre, randomized study included patients with a single prior AF ablation, but with recurrent AF and reconnected pulmonary veins (PVs). Conventional ablation generally included PV re-isolation; however, additional ablation was permitted per physician discretion. In the FIRM arm, beyond PV re-isolation, basket catheter-based FIRM mapping created dynamic animations of putative rotors, which were targeted for ablation. Between May 2016 and July 2019, 269 subjects were randomized, with 243 subjects completing 12-month follow-up. Ablation beyond re-pulmonary vein isolation, the FIRM vs. Conventional arms did not differ significantly: cavo-tricuspid isthmus -9.0% vs. 15.3%, caval vein isolation -1.5% vs. 0.8%, non-PV trigger -2.2% vs. 3.8%, other -11.9% vs. 13.0%. Single procedure 12-month freedom from AF/atrial tachycardia/atrial flutter-recurrence was 63.3% (76/120) vs. 59.0% (72/122) in the FIRM and Conventional arms (P = 0.3503). Efficacy was similar in the paroxysmal and persistent AF subgroups (P = 0.22 and P = 0.48). The 10-day and 12-month safety endpoints were achieved in 93.3% vs. 93.8% (P = 0.89) and 88.4% vs. 93.4% (P = 0.22) in the FIRM and Conventional arms, respectively.
Conclusions: In REDO-FIRM, as compared to standard ablation, FIRM-guided ablation did not provide additional efficacy in redo ablation procedures, but FIRM-guided ablation was equally safe. Additional studies are necessary to identify any potential population able to benefit from FIRM-guided ablation.
Competing Interests: Conflict of interest: S.G.S. received speaker’s honoraria and or honoraria for advisory board activities from Medtronic, Abbott, Daiichi Sankyo, Edwards, AstraZeneca, BayerVital, Bristol Myer Sqibb and Boeringer Ingelheim, and participated in clinical trials with Abbott, Medtronic and Ablacon. J.M.M. received speaker’s honoraria and honoraria for training support from Medtronic, Boston Scientific, Biotronik and Biosense Webster, is consultant of Biosense-Webster and MediLynx, and received speaker’s honoraria from Abbott as well as Royalties vom Elsevier, Inc. P.S. is member of advisora board of Abbott, Biosense-Webster, Boston Scientific and Medtronic. V.Y.R. reports being an unpaid consultant to Abbott Inc; in addition, he has disclosures unrelated to this manuscript, which are detailed in the Supplementary material online, appendix. D.W. stated the following disclosures: Abbott: Research (modest), ACC Foundation: consulting (modest), Atricure: Research (modest), Biosense Webster: Research (modest), consulting (modest), Boston Scientific: Research (modest), consulting (modest). The other authors report no conflicts of interest.
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