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Highlights • Ablation Index-guided ablation allows for ablation lesions of consistent depth. • Ablation Index-guided ablation is limited by ignoring local wall thickness. • Local atrial wall thickness is associated with acute pulmonary vein reconnection. • Wall thickness adjusted Ablation Index targets may improve ablation outcomes., Background Although Ablation Index (AI)-guided ablation facilitates creation of lesions of consistent depth, pulmonary vein (PV) reconnection is still commonly observed after AI-guided pulmonary vein isolation (PVI). The present study aimed to investigate the impact of local left atrial wall thickness on the incidence of acute PV reconnection after AI-guided atrial fibrillation (AF) ablation. Methods and results Seventy patients (63% paroxysmal AF, 67% male, mean age 63 ± 8 years) who underwent preprocedural CT imaging and AI-guided AF ablation were studied. Occurrence of acute PV reconnection after initial PVI was assessed after a 30-minute waiting period. Ablation procedures were retrospectively analyzed and each ablation circle was subdivided into 8 segments. Minimum AI, force-time integral, contact force, ablation duration, power, impedance drop and maximum interlesion distance were determined for each segment. PV antrum wall thickness was assessed for each segment on reconstructed CT images based on patient-specific thresholds in Hounsfield Units. Acute reconnection occurred in 27/1120 segments (2%, 15 anterior/roof, 12 posterior/inferior) in 19/140 ablation circles (14%). Reconnected segments were characterized by a greater local atrial wall thickness, both in anterior/roof (1.87 ± 0.42 vs. 1.54 ± 0.42 mm; p

Background Cryoballoon ( CB ) ablation is widely performed for pulmonary vein isolation ( PVI ) in patients with atrial fibrillation ( AF ). Anatomic variations in patient pulmonary vein ( PV) anatomy are believed to impact short‐ and long‐term procedural success of CB PVI . Methods and Results We hypothesized that failure of initial PV isolation with a standard technique (ie, requiring >2 freeze cycles per PV and/or radiofrequency ablation [RFA] to achieve PV isolation) during index CB PVI procedures would be associated with decreased freedom from AF . We examined a cohort of 177 consecutive patients with drug‐refractory AF who underwent CB PVI with a 28‐mm balloon second‐generation CB device. Mean follow‐up time was 19±9 months. Forty‐three patients had AF recurrence after the 90‐day blanking period after ablation. In 40 patients, acute isolation of one or more PV s could not be achieved by CB ablation with the standard technique (single freeze with or without bonus freeze). To obtain complete acute PVI , 15 patients received extra freeze applications, 20 required supplemental RFA , and 5 received both extra freeze applications and supplemental RFA . Multivariate regression analysis revealed supplemental RFA use during index CB PVI procedures was independently associated with a threefold increased risk of AF recurrence (adjusted hazard ratio, 3.01; 1.45–10.87; P =0.003). Conclusions Use of supplemental RFA during CB PVI procedures to assist with isolation of one or more PV s was independently associated with increased risk of AF recurrence. Use of additional freezes to achieve PVI did not increase the risk for recurrent AF .