Association between left atrial wall thickness and residual potential after pulmonary vein antral isolation in patients with atrial fibrillation receiving Ablation Index-guided ablation
Abstract Background For the improvement of efficacy in radiofrequency catheter ablation (RFCA) of pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF), fixed target Ablation Index (AI) value has been recommended regardless of individual and regional differences of left atrial wall thickness (LAWT). Objective To evaluate the association between LAWT and residual potential (RP) after first pass encirclement of PVI in AF patients receiving AI-guided PVI. Method A total of 116 patients (29% persistent AF) undergone AF RFCA using AI-guided PVI were included. Using SmartTouch catheter or SmartTouch SF catheter (Biosense Webster Inc., CA, US), point-by-point ablation was delivered at 30–40W on the anterior/roof segments and 25–30W on the posterior/inferior/carina segments. AI targets were 450 on the anterior/roof segments and 350 on the posterior/inferior/carina segments. After first encirclement of PVI was performed, RP was evaluated. LAWT was evaluated by 3-dimensional wall thickness map using computed tomographic images. LAWT values of ablation regions were graded by LAWT in each segment of PV antrum (Figure). Results Among a total of 1564 PV segments, RP was observed in 106 segments (6.8%). Left superior, inferior PV ridges and right superior PV roof segments were the most, second, and third thickest area among 14 PV segments (mean LAWT grade 5.09±1.08, 3.34±1.70, and 2.32±1.11, respectively). Mean LAWT grade was lower in segments with RP than those in without RP (2.74±1.80 vs. 2.07±1.28, p<0.001, Figure). In segments applied AI 450 (anterior/roof), segments with RP showed significantly thicker LAWT than those without RP (mean LAWT grade 3.65±2.01 vs. 2.57±1.56, p<0.001). In posterior/inferior/carina segments applied AI 350, there was no significant difference in mean LAWT between segments with and without RP (1.80±0.77 vs. 1.75±0.83, p=0.744). Conclusion Delivering same AI during PVI, thicker LAWT was associated with higher incidence of RP after first pass encirclement of PV in anterior/roof area. Tailored AI should be considered by LAWT to improve acute outcome of PVI. LAWP RP Funding Acknowledgement Type of funding source: None