Introduction: Cardiac tamponade complicating pulmonary vein isolation (PVI) for atrial fibrillation (AF) is a complication that can increase morbidity and mortality, with a reported incidence of 1-2%. Radiofrequency energy delivery is a known cause for tamponade. Ablation Index (AI) is a novel ablation quality marker that incorporates contact force, time, and power in a weighted formula.

Aim: We hypothesized that use of Ablation Index reduces the incidence of cardiac tamponades.

Methods: A total of 1073 consecutive drug-refractory AF patients (59% male, median age 67 years, 41% paroxysmal) underwent PVI. 686/1073 (64%) PVIs were performed without AI (236/686 (34%) with non-contact force catheter, 450/686 (66%) with contact force catheter) and 387/1073 (36%) PVIs were performed with AI. Non-AI PVIs were performed using a force-time integral 400 gr*sec for anterior and 300 gr*sec for roof/posterior/inferior antral segments. AI targets were 600 for anterior and 450 for roof/posterior/inferior antral segments.

Results: A total of 24/1073 (2,2%) hemodynamically relevant cardiac tamponades requiring pericardial drainage occurred, in the non-AI group 17/686 (2,4%) and in the AI group 7/387 (1,6%) (p=0,0015). In the non-AI group, there were 4/236 (1,7%) tamponades in the non-contact force catheter group and 13/450(2,9%) tamponades in the contact force catheter group (p=0,0025). Mean procedure time (±SD) in the AI group and non-AI group was 164 ± 51 and 186 ± 53 minutes (p<0,0001), respectively. Mean ablation time (±SD) in the AI group and non-AI group was 44 ± 20 and 56 ± 25 minutes (p<0,0001), respectively. Mean fluoroscopy time (±SD) in the AI group and non-AI group was 5 ± 3 and 7 ± 5 minutes (p<0,0001), respectively.

Conclusions: Use of Ablation Index significantly reduces the incidence of cardiac tamponades complicating pulmonary vein isolation by 33%. This reduction is not caused by use of contact force catheters. Possibly, the shorter procedure and ablation times contributed to the reduction of cardiac tamponades.