Shorter interlesion distance is associated with a longer procedure time but not with poorer acute results of pulmonary vein isolation: results from a prospective ablation index registry
Authors: Gasimova N , Kropotkin EB , Ivanitsky EA , Kolunin GV , Nechepurenko AA , Shavshin DA , Antolic B , Kovalev KS , Lebedev DS , Mikhaylov EN 
Published: May 2021

Abstract

Funding Acknowledgements
Type of funding sources: Other. Main funding source(s): This work was supported by the Ministry of Science and Higher Education grant (Russian Federation President Grant) #MD-2314.2020.7.
Background/Introduction. Radiofrequency ablation (RFA) is the mainstay of invasive management of atrial fibrillation (AF). Amongst a variety of performance indicators, interlesion distance (ILD) has a potential to become a guiding one. Uptodate clinical AF RFA protocols suggest that ILD has to be less than 6 mm, however the research is still lacking in regard to its actual targeted value.
Purpose. The aim of the research is to study a relationship between ILD and first-pass isolation (FPI) in ablation-index guided AF ablation procedures.
Methods. This was a prospective observational multicenter study. Data were derived from the web-based system. Pulmonary veins (PV) isolation procedures were performed according to the local practice, and RFA settings depended on operators’ preferences. A total of 446 patients were enrolled, 407 of them underwent first-time AF ablation, data on ILD available in 322 subjects (177 (55%) males, mean age 62 ± 9 years old, 259 (80%) with paroxysmal AF). A mean ILD was calculated manually in each case as a sum of all ILDs divided by number of ablation tag points. FPI was considered in cases when no additional applications were required for bidirectional PV block following creation of a one circle around ipsilateral PVs and after a 20-min waiting period. Patients were divided into two groups according to ILD (Group 1 ILD≤ 4 mm, 163 patients and Group 2 ILD &gt; 4m, 159 patients) post-procedurally.
Results. The mean procedure time was 102 ± 52 min, the median fluoro time was 9 min [IQR 6; 15]. The following VisiTag parameters were used: the median target ablation index 400 [IQR 400; 500] on the left atrial anterior wall and 380 [IQR 380; 400] on the posterior segments, the median minimal contact force 3g [IQR 3; 4], median minimal time per a point - 4 sec [IQR 3; 15], mean catheter stability 3 mm (ranged between 2.5 and 3 mm). In 261 (81%) cases operators used 3 mm ablation tag size, and in 19% - 2 mm. The mean ILD was 4,1 ± 1,0 mm (3,2 ± 0,5 mm in Group 1 vs 4,6 ± 0,5 mm Group 2). FPI was achieved in 189 (59%) cases. In the "ILD ≤ 4 mm" group FPI was achieved in 93 (49,2%) cases and there were 96 (50,8%) cases of durable FPI in the "ILD &gt;4 mm" group (χ2 = 2,4, p = 0,124). The mean procedure time was 111 ± 46 min and 100 ± 35 min in Group 1 and 2 (p = 0,01), respectively. The mean fluoro time was 13 ± 4 min and 11 ± 4 min in Group 1 and 2 (p = 0,08), respectively
Conclusion(s). The results of our multicenter study suggest that shortening of the distance ≤4 mm has no effect on the achievement of first-pass PV isolation, but required more procedure and relatively more X-ray exposure time.