Results of atypical flutter ablation in the era of high density electroanatomical mapping (the RAFAELA study)

Introduction Atypical flutter (AFL) ablation is a technically challenging procedure with limited long-term efficacy according to prior studies and not exempt from risks. Purpose The aim of this study was to describe the efficacy, in terms of acute and long-term rhythm management, and safety of AFL ablation guided by high-density electroanatomical mapping in a population of contemporary patients. We aimed also to compare results between different patient populations. Methods From june 2015 to November 2021, all consecutive AFL ablation procedures guided by high-density electroanatomical mapping were included in the study. Patients were classified in 4 groups according to history of atrial catheter ablation, cardiac surgery, congenital heart disease or none of the above (considered as primary disease). Activation and voltage mapping were used to define AFL circuits and substrate. After AFL characterization, radiofrequency lesions were performed to operator’s discretion until AFL termination. Programmed atrial stimulation was repeated to test AFL inducibility, and any sustained induced atrial arrhythmia was ablated. Procedural success was defined as termination of every induced AFL and no-inducibility. A 3-month blanking period was considered. Follow-up included visits with ECG and/or 24h Holter-ECG at 3, 6, 12, 24 months, and from there on according to physician’s discretion. Results 190 AFL procedures in 160 patients were included. Patient and procedural characteristics of the global cohort as well as different patient populations (27% primary, 37.9% post-ablation, 15.3% post-surgery, 20% congenital heart disease (CHD)) can be found in figure 1 (table). Survival free from atrial arrhythmias in pre-specified groups is shown in figure 2 (left). Overall, a 2-year ∼50% recurrence rate was observed, with a tendency to better outcome in patients with congenital heart disease (∼70%), over the rest of the groups, which behaved similarly (p=0.281). Progression to permanent atrial arrhythmia was lower in this subgroup (2.7% vs 23.5%, p=0.028), as shown in figure 2 (right), probably related to higher rhythm control efforts and stricter follow-ups. CONCLUSIONS In the era of high-density electroanatomical mapping, acute procedural success is achievable in the majority of patients, but recurrence rate remains high, with an approximate 50% 2-year recurrence rate except for congenital heart disease patients, which tend to show better survival free from atrial arrhythmias.Figure 1Figure 2