Efficacy, safety and very long term recurrences of cavo-tricuspid isthmus-dependent atrial flutter ablation: a large multicenter observational study

Background Transcatheter ablation of the cavo-tricuspid isthmus (CTI) is the first-line therapy for typical atrial flutter (AFL). However, multi-center data on very long-term outcomes, including recurrence rates, coexistence of atrial fibrillation (AF), and procedural safety in a real-world setting, remain limited. Methods We conducted a retrospective, multi-center registry analysis including all patients having undergone a first procedure of CTI ablation for a common typical AFL, with diagnosis based on 12-leads ECG, between 2001 and 2020. Data on baseline demographics, the prevalence of concomitant AF, and long-term outcomes were collected. Endpoints included typical AFL recurrence, time to recurrence, the need for re-do procedures, and procedural complications. Results The cohort (N=542) had a median age of 66.0 [58.0-72.0] years, was predominantly male (78.3%, n=593), and 31.6% (n=239) had concomitant AF. Procedural and fluoroscopy times had a median time of 60 [50-85] min and 12.5 [7.5-19.8] min, respectively. After a median follow-up of 82 [44.0-136.0] months, the recurrence of typical AFL was observed in 15.2% of patients. The median time to recurrence was 291 days [IQR 38-1030 days]. A redo procedure was performed in 65% of all patients with AFL recurrences and in 10% of all cases. The overall rate of procedural complications was 0.8% (n=6), primarily consisting of vascular access site issues. No significant differences were observed in efficacy (84.5% vs 81.3% respectively; p=0.42) between 8 mm non-irrigated ablation catheters (n=646) and irrigated ablation catheters (n=80). Conclusion In this large, real-world multi-center registry with a long-term follow-up, CTI-dependent AFL ablation show a high success rate (84.8%) and a favorable safety profile. The high prevalence of concomitant AF underscore the progressive nature of atrial myopathy in this population, highlighting the need of persistent long-term monitoring for both AFL recurrence and new-onset AF. Recurrences, while infrequent, can occur very late, highlighting the need for long-term surveillance.