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CA-530-03 TAILORED ABLATION INDEX BASED ON LEFT ATRIAL WALL THICKNESS ASSESSED BY COMPUTED TOMOGRAPHY FOR PULMONARY VEIN ISOLATION IN PATIENTS WITH ATRIAL FIBRILLATION

      Background

      Although left atrial wall thickness (LAWT) is known to be diverse, fixed target Ablation Index (AI) value has been recommended in radiofrequency catheter ablation (RFCA) of pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF).

      Objective

      To evaluate the efficacy of tailored ablation for PVI based on LAWT assessed by cardiac computed tomography (CT).

      Methods

      LAWT was evaluated by cardiac CT. The thick segment was defined as the segment including ≥LAWT grade 3 (≥1.5 mm) among 14 prespecified pulmonary vein (PV) segments (Figure A). Using SmartTouch SF catheter (Biosense Webster Inc., CA, US), point-by-point ablation was delivered at 40W on the anterior/roof segments and 25-35W on the posterior/inferior/carina segments. In the fixed AI group, AI targets were 450 on the anterior/roof segments and 350 on the posterior/inferior/carina segments regardless of LAWT. In the tailored AI group, AI targets were increased to 500 on the anterior/roof segments and 400 on the posterior/inferior/carina segments when ablating the thick segment. After PVI, acute reconnection defined by the composite of residual potential and early reconnection was evaluated.

      Results

      A total of 156 patients (mean age 60±9 years, men 73%, and paroxysmal AF 72%) undergone AF RFCA using AI-guided PVI were consecutively included (86 for fixed AI group and 70 for tailored AI group). There were no significant differences in the baseline characteristics of the two groups. In the tailored AI group, 57 patients (81.4%) had at least one thick segment (mean 2.7±2.1 segments among prespecified 14 PV segments). The prevalence of thick segments among 14 PV segments is presented in Figure B. Tailored AI group showed a significantly lower rate of segments with acute reconnection than the fixed AI group (8% vs. 5%, p=0.007). Tailored AI group showed a trend for shorter ablation time for PVI between the two groups (36±8 min for tailored AI group vs. 39±8 min for fixed AI group, p=0.051). There was no significant procedure-related complication in both groups.