Causes for recurrence after personalized radiofrequency catheter ablation for paroxysmal atrial fibrillation and pulmonary vein reconnection site characteristics

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND: Personalized pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (PAF), tailoring the ablation index (AI) to the left atrial wall thickness (LAWT), has proven to be a highly efficient method with excellent arrhythmia free survival rates. However, the number and location of pulmonary vein (PV) reconnection sites in patients with arrhythmic recurrences after personalized PVI is not known. PURPOSE: We aimed to analyze the PV reconnection sites and the probable causes responsible for these PV reconnections during REDO procedures after personalized atrial fibrillation (AF) ablation. METHODS: Consecutive patients referred for a REDO procedure, after a personalized ablation protocol for PAF, were included in the analysis. During the index procedure and using ADAS 3DTM imaging platform for segmentation, the LAWT maps were obtained from multidetector computerized tomography (MDCT) and, thereafter, imported into CARTO 3 navigation system. If reconnection of a PV was confirmed, the LAWT of the reconnection site was analyzed. Patients who lost follow-up were excluded. RESULTS: Among 251 consecutive patients who underwent personalized PVI from April 2019 to July 2021, 45 (17,9%) had recurrence of atrial tachyarrhythmias after a mean follow-up of 1,4 ± 0,8 years. Of them, 28 underwent a REDO AF ablation procedure. 26 patients (93%) had PV reconnections [17 (60%) had both right and left reconnected PVs, 5 (18%) isolated right PV reconnection and 4 (14%) isolated left PV reconnection]. Overall, there were 76 reconnection points (40 in right PVs and 36 in left PVs). Mean LAWT in right and left PV reconnection sites was 2 ± 0,8 mm and 3,1 ± 1,2 mm, respectively. Most frequent sites of PV reconnections were anterosuperior and anterior carina for RPV (accounting for 55% of reconnection points) and anterosuperior, anterior ridge and anteroinferior for LPV (75%). Only 2 PV reconnections (3%) occurred in areas with LAWT < 1 mm. Analyzing the possible causes for PV reconnections, we found a causal relationship in 20 reconnected points (26%): gaps in the ablation line (distance between two adjacent VISITAG™ > 6 mm) in 5, lower ablation index than pre-specified in the personalized ablation protocol at a given point in 15, and absence of right carina ablation line in 5 cases. Catheter instability and misinterpretation of the color-coded LAWT were the main causes of these suboptimal (under target RF dosing) ablation lesions. Conversely, among 6 patients with no gaps and optimal ablation lesions according to the pre-specified protocol, only 1 had PVs isolated during the REDO procedure. CONCLUSION: Most of the patients with AF recurrence after a personalized AF ablation had PV reconnections. Reconnection points were more frequently present in thicker segments of both PVs. GAPS in the ablation line, suboptimal ablation lesions and catheter instability are associated with PV reconnections. [Figure: see text]