Efficacy of a Novel Ablation Index Algorithm for Cavotricuspid Isthmus Ablation Using a Flexible‐Tip Ablation Catheter

ABSTRACT Introduction AutoMark Index (AI) is a novel ablation algorithm integrating contact force (CF), radiofrequency (RF) current, and application duration to provide real‐time lesion formation feedback. Data of AI using a flexible‐tip RF ablation catheter for cavotricuspid isthmus (CTI) ablation remain limited. The objective was to evaluate the efficacy and safety of AI‐guided CTI ablation. Methods Consecutive 148 patients undergoing CTI ablation with a CF‐sensing flexible‐tip ablation catheter were included. Outcomes using an AI‐guided protocol (50 W, targeting AI of 50; AI‐50 group, 62 patients) were compared with a conventional protocol (40 W for 20 s; 40‐W group, 86 patients). Results The first‐line success rate showed no difference between the two groups (40‐W group: 72/86 [84.7%] vs. AI‐50 group: 51/62 [82.2%], p = 0.81). The total RF application showed no difference (40‐W group: 12 [9.5–15] vs. AI‐50 group: 12 [9.7–16], p = 0.50); however, significant differences were observed in the total RF duration (40‐W group: 274 [211–372] s vs. AI‐50 group: 180 [138–249] s, p < 0.001), the RF duration for initial block (40‐W group: 225 [163–323] s vs. AI‐50 group: 149 [109–221] s, p < 0.001), and CTI procedural time (40‐W group: 9.2 [6.0–14.6] min vs. AI‐50 group: 6.3 [4.5–9.7] min, p = 0.007). No significant differences were observed in the mean CF, average temperature, and CTI length between the two groups. No major complications were observed in either of the groups. Conclusion AI‐guided CTI ablation protocol is efficient in shortening RF duration for acute bidirectional CTI block and CTI procedure time compared to the conventional 40 W ablation protocol.