AUTHOR=Cai Chi , Wang Jing , Niu Hong-Xia , Chu Jian-Min , Hua Wei , Zhang Shu , Yao Yan 

TITLE=Optimal Lesion Size Index for Pulmonary Vein Isolation in High-Power Radiofrequency Catheter Ablation of Atrial Fibrillation

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2022.869254

DOI=10.3389/fcvm.2022.869254

ISSN=2297-055X

ABSTRACT=Background: Although both of high-power (HP) ablation and lesion size index (LSI) are the novel approach to make effective lesions during pulmonary vein isolation (PVI) for atrial fibrillation (AF), the optimal LSI in HP ablation for PVI is still unclear. Our study sought to explore the association between LSI and conduction gap formation, and investigate the optimal LSI in HP ablation for PVI.
Methods：One hundred five consecutive AF patients who underwent HP ablation guided by LSI (LSI-guided HP) for PVI were retrospectively enrolled. Each ipsilateral PV circle was subdivided into 4 segments and ablation power was set to 50 W with target LSI values at 5.0 and 4.0 for anterior and posterior walls, respectively. We compared the LSI values with and without conduction gaps after the initial first-pass PVI.
Results: PVI was achieved in all patients and the incidence of first-pass PVI was 78.1% (82/105). A total of 6842 lesion sites were analyzed, and the acute conduction gaps were observed in 23 patients (21.9%) with 45 (0.7%) lesion points. The gap formation was significantly associated with lower LSI (3.9 ± 0.4 vs. 4.6 ± 0.4, P <0.001), lower force-time integral (82.6 ± 24.6 vs. 120.9 ± 40.4 gs, P <0.001), lower contact force (5.7 ± 2.4 vs. 8.5 ± 2.8 g, P <0.001), shorter ablation duration (10.5 ± 3.6 vs. 15.4 ± 6.4 s, P <0.001) and lower temperature (34.4 ± 1.4 vs. 35.6 ± 2.6 ℃, P <0.001). By receiver operating characteristic analysis, the LSI had the highest predictive value for gap formation in all PVs segments, with a cutoff of 4.35 for effective ablation (sensitivity 80.0%; specificity 75.4.0%, areas under the curve: 0.87). The LSI of 4.55 and 3.95 had the highest predictive value for gap formation for the anterior and posterior wall, respectively.
Conclusion: Using LSI-guided HP ablation for PVI, more than 4.35 of LSI for all PVs segments showed the best predictive value to avoid gap formation for achieving effective first-pass PVI. The LSI of 4.55 for the anterior wall and 3.95 for the posterior wall were the best cutoff values for predicting gap formation, respectively.