LAUSR

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by a grant [HI21C0011] from the Ministry of Health and Welfare, a grant [NRF-2020R1A2B5B01001695] from the Basic Science Research Program run by the National Research Foundation of Korea (NRF) which is funded by the Ministry of Science, ICT & Future Planning (MSIP), and a grant [RS-2022-00141473] from Cross-ministerial tasks. Background High-power short-duration (HPSD) ablation generates wide and contiguous but shallow lesions by radiofrequency (RF) resistive heating. It is unknown whether RF energy titration has additional benefits depending on the atrial wall thickness. Purpose We aimed to compare the efficacy and safety of HPSD energy titration depending on left atrial wall thickness (LAWT) during circumferential pulmonary vein isolation (CPVI) in patients with paroxysmal atrial fibrillation (PAF). Methods We prospectively randomized 224 patients with PAF (69.2% males, 59.3±12.0-years-old) into either the LAWT-guided CPVI group (WT, n=113) or the conventional CPVI group (Control, n=111). We delivered 15s of constant RF (contiguous lesion 2mm dots, FlexAbility) at 60W in the Control group but titrated the RF duration in the WT group (15 s at LAWT>2.1mm, 13s at 1.4–2.1mm, and 11s at <1.4mm) referencing the computed tomogram-myocardial thickness color map. The primary endpoints were safety and AF recurrence after a single procedure; the secondary endpoints were the procedure time, cardioversion rate, and response to anti-arrhythmic drugs (AADs). Results After a mean follow-up of 13.4±7.0 months, the clinical recurrence rate (13.3% vs. 8.1%, log-rank p=0.302) and the complication rate (8.0% vs. 4.5%, p=0.427) did not differ between the two groups. The total procedure time (p=0.391) and cardioversion rate (p=1.000) did not significantly differ between the two groups. During the final follow-up, sinus rhythm was maintained without AADs in 72.6% of the WT group and 80.2% of the Control group (p=0.237). Conclusions LAWT-guided energy titration resulted in efficacy and safety equivalent to that of constant 15s 60W-HPSD CPVI in patients with PAF.