Background

Atypical flutter (AFL) is a rare macro-reentry tachycardia often arising from the left atrium, especially in patients with previous left atrial ablation. Due to rising number of patients undergoing left atrial ablation for the treatment of atrial fibrillation (AF), rising incidence of AFL is observed. Despite catheter ablation of AFL is long established there is low evidence regarding the long time outcome in the era of high density mapping systems and modern generation of RF ablation catheters.

Methods

In this prospective monocentric register-study (ATRIUM, DRKS-ID: DRKS00013013) patients undergoing AFL ablation between January 2015 and April 2021 were included. Procedural success was defined as acute termination of AFL during RF energy application for a substrate-based or an anatomical-based ablation line plus verification of a bidirectional line. Follow up was performed 6, 12, 24 and 36 months after ablation and in case of symptoms by (holter-)ECG. Recurrence was defined as every regular supraventricular tachycardia lasting longer than 30 seconds.

Results

The study cohort consists of 91 individuals (mean age: 70 ±9 years, male: 52 (57.1%), body mass index: 28.6 ± 4.4 kg/m2, CHA2DS2-Vasc-Score: 3.7 ±1.3, prior left-atrial ablation: 75 (82.4%)). In the index-procedure 100 AFL (perimitral: 56 (56%), roof-dependent: 36 (36%), other: 8 (8%)) had been deduced by the use of a 3D mapping-system (Carto: 57 (62.6%), EnSite Precision: 24 (26.4%), Rhythmia: 10 (11.0%)). Acute procedural success was achieved in 88.9% of AFL. Mean procedural duration was 205 ±84 minutes. Mean ablation time was 29 ±26 minutes. Mean follow-up time was 24 ±20 months. After 12, 24 respectively 36 months, 81.7%, 69.0% respectively 69.0 % of the patients remained free from any regular atrial arrhythmia.  

Conclusion

By the use of modern 3D mapping-systems acute termination of AFL during RF energy application is possible in the vast majority of patients. Remarkably, most of the patients remained free from any arrhythmia recurrence also during a long-term follow-up.