The aim of this study was to evaluate the impact of the size of the isolated surface area and non-ablated left atrial posterior area after extensive encircling pulmonary vein isolation (EEPVI) for non-paroxysmal atrial fibrillation (AF) on arrhythmia recurrence. This study included 132 consecutive persistent AF patients who underwent EEPVI guided by Ablation Index (AI). The isolated antral surface area (IASA) excluding the pulmonary veins, the non-ablated left atrial (LA) posterior wall surface area (PWSA), the ratio of IASA to LA surface area (IASA/LA ratio), and the ratio of PWSA to LA surface area (PWSA/LA ratio) were assessed using CARTO3 and the association with AF and atrial tachycardia (AT) recurrence was examined. At a mean follow-up of 13.2 ± 7.3 months, sinus rhythm was maintained in 115 (87%) patients. In the univariate Cox regression analysis, the factors that significantly predicted AT/AF recurrence were a history of heart failure, a higher CHADS-VASc score, a larger LA diameter, and a larger PWSA/LA ratio. Multivariate Cox regression analysis revealed that the independent predictors of AT/AF recurrence were LA diameter [hazard ratio (HR) 1.120 per 1 mm increase; 95% confidence interval (CI) 1.006-1.247; P = 0.039] and PWSA/LA ratio (HR 1.218 per 1% increase; 95% CI 1.041-1.425; P = 0.014). Receiver operating characteristics curve analysis yielded an optimal cut-off value of 8% for the PWSA/LA ratio. The Kaplan-Meier survival curve showed that patients with a larger PWSA/LA ratio had poorer clinical outcomes (Log-rank P = 0.001). A larger PWSA/LA ratio was associated with a high AT/AF recurrence rate in patients with non-paroxysmal atrial fibrillation.

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