Optimizing first-pass isolation success in left pulmonary vein ablation: a randomized study on radiofrequency ablation line design at the left atrial ridge

Abstract Background/Introduction Catheter ablation with pulmonary vein isolation (PVI) is the standard treatment for atrial fibrillation (AF). Radiofrequency ablation (RFA) remains the most effective modality, with the CLOSE protocol used for successful PVI. However, anatomical challenges at the left atrial (LA) ridge between the left pulmonary veins (LPV) and left atrial appendage (LAA) can affect catheter stability and operator’s choice of ablation line construction, potentially lowering the isolation rate. This study aims to optimize ablation line design in this region to improve first attempt isolation of the LPV (FALPVI) and enhance AF ablation outcomes. Purpose The purpose of this randomised study is to investigate ablation line design effect in this region on FALPVI. Methods In this single-center, prospective, randomized study, we included patients treated for paroxysmal or persistent AF from August 2023 to August 2024. Patients were randomly assigned to undergo LPV ablation on either the venous or LAA side of the LA ridge using the CLOSE protocol. The primary outcome was FALPVI. The LA and pulmonary vein anatomy were constructed using a multipolar mapping catheter, and intracardiac echocardiography was used to ensure correct, group-specific positioning and stable contact before each ablation. Results Our study included 40 patients, with 20 patients in each randomization group (Figure 1). Among them, 17 (43%) had persistent AF, and the remainder had paroxysmal AF. The median CHA2DS2-VA score was 2 (IQR 1). Patient and procedural characteristics are summarized in Figure 2. First-attempt isolation of the left pulmonary veins was achieved in 16 (80%) patients in the venous side group, compared to 7 (35%) in the LAA side group (p = 0.001). In cases of non-FALPVI, the LA ridge and/or carina were the primary gap sites, with 1 patient in the venous side group (30%) and 7 patients in the LAA side group (100%) showing gaps (p < 0.001). The LAA side group experienced significantly longer LPV ablation times (Figure 2). One patient in the venous side group experienced tamponade, requiring pericardiocentesis during right pulmonary vein ablation. Conclusion Our study demonstrates that ablation on the venous side of the LA ridge during circumferential LPV ablation significantly improves FALPVI rates compared to the LAA side approach. These findings suggest that optimizing ablation line design on the venous side may enhance the efficacy and long-term success of PVI in AF ablation.Randomisation groups Patients' and procedural characteristics