Introduction: Left atrial (LA) ablation procedures using radiofrequency (RF) have been associated with a significant number of endoscopic detected thermal esophageal lesions (EDEL). Recently ablation index (AI) was introduced in CARTO3 LA procedures allowing ablation with stable lesion size and depth. The aim of the study was to compare complications including EDEL occurring after conventional contact force guided AF ablation (CFG) and ablation using AI.

Methods: Extracting data from our institutional AF ablation registry we analyzed the last consecutive 100 AF ablation procedures with CFG with the first 100 procedures using AI. Redo procedures were excluded. Circumferential PVI and voltage guided ablation was performed. In the CFG group lines were dragged (CF targets 8 to 20 g), in the AI group point-by-point ablation was performed (inter-lesion distance ≤6 mm, AI of 500 anteriorly and 360 posteriorly. Esophageal erosions or ulcers ≤ 5mm were classified as type 1 lesions, ulcers > 5 mm as class 2 lesions. Follow up included 72h Holter ECG 3 and 12 months after ablation.

Results: Mean age of CFG group was 68.4 ±8.9 years and 57% men, AI group patients were 68.2±8.9 year old  and  in 56% men. Procedure duration was similar (CFG: 205 ± 60 minutes vs. AI: 193 ±58,  P = 0.14). Endoscopy performed within 1 to 3 days after ablation revealed pathological findings not related to ablation in 31.5 % of patients, including reflux esophagitis (7%), Barrett esophagus (6%), hiatal hernia (4.5%), gastral erosions (15.5%). EDEL occurred in 6% (4% type 2) and 5% (2% type 2) in CFG and AI group (n.s.). All EDEL healed under high dose PPI therapy within 2-3 weeks without developing fistula. No predictors could be identified for occurrence of EDEL, neither under patient characteristics nor under procedural data. Intraprocedural complications were described in 5% vs. 4% of the patients in the CFG and the AI group, respectively. One-year outcome data will be presented at DGK 2021.

Conclusions: Both ablative methods were comparable with respect to complications, in particular the number of EDEL. One-year outcome will be presented at DGK 2021.