Evaluation of ablation index-guided linear lesions formation for left atrial arrhythmia treatment

Background Catheter based left atrial linear lesion ablation is commonly performed in patients with atrial fibrillation (AF) and complex left atrial substrate or in patients presenting with macro-reentrant left atrial tachycardia (LAT). Aims To assess acute and long-term effectiveness, procedural viability and safety of ablation index (AI)-guided compared to contact force (CF)-guided ablation of left atrial linear lesions. Methods Consecutive patients undergoing left atrial ablation for AF or LAT including left atrial linear lesions ablation either guided by AI or CF without AI were prospectively enrolled. Characteristics of anterior lines (AL), mitral isthmus lines (MIL), roof lines (RFL) and posterior wall isolation (PWI) were systematically analyzed in both cohorts. Procedural feasibility, safety, acute and long-term block of linear lesions as well as clinical outcome in terms of arrhythmia recurrence were assessed. Results A total of 313 patients were included. 260 patients (83.1%) underwent AI-guided ablation and 53 patients (16.9%) CF-guided ablation. Complete conduction block was comparable between study groups (94 vs. 95% for AL, 94 vs. 95% for AL100 vs. 99% for RFL and 100 vs. 100% for PWI). Acute block of MIL was significantly more often achieved in AI-guided ablation (100 vs. 67%, p = 0.0004). No significant difference in persistence of conduction block for AL (p = 0.47), MIL (p = 0.57), RFL (p = 0.18) or PWI (p = 1) could be observed between AI-guided or CF-guided ablation during repeat ablation. Survival analysis showed no significant differences in estimated arrhythmia free survival (p = 0.45). Periprocedural complications occurred in 22 patients (7%) with equal distribution in CF-guided and AI-guided ablation (p = 0.31). Conclusion AI-guided ablation is associated with significantly higher rates of acute conduction block across MIL, shorter RF times and lower FTI for AL and RFL while complication rates and long-term clinical outcome are comparable to non-AI-guided ablation.