Outcome after catheter ablation for left atrial flutter.

Objectives. Left atrial flutter has been reported in up to 10% of patients following pulmonary vein isolation or cardiac surgery. Left atrial flutter is typically highly symptomatic, responds poorly to medical antiarrhythmic treatment, and is often treated by catheter ablation. We aimed to investigate midterm freedom from recurrent arrhythmia after catheter ablation for left atrial flutter. Design . In the National Danish Ablation Registry, we identified consecutive patients, who had undergone catheter ablation for left atrial flutter between 1 January 2014 and 1 April 2017 at our centre. Results. A total of 53 patients (median age 68 years (IQR 60-71) 37 (70%) male) were included. Forty-two patients had prior left atrial catheter ablation procedures (79%), one patient prior ablation for classic atrial flutter (2%), four patients had prior surgery for congenital heart disease (8%), and six patients (11%) had no previous cardiac intervention. Acute procedural success, defined as non-inducibility of any atrial arrhythmia, was achieved in 45 of 53 patients (85%). During midterm follow-up (mean 20 ± 12 months), 26 patients experienced an episode of recurrent atrial arrhythmia. Median EHRA-score was 3 (range 2-4) before catheter ablation and reduced to median 1 (range 1-3) evaluated at follow-up visits after three and twelve months (both p  < .001, Wilcoxon rank test). Conclusion. Left atrial flutter is preceded by catheter ablation or cardiac surgery in 89% of patients. Acute procedural success is achieved in majority of patients and ablation reduces symptoms effectively. During midterm follow-up, almost half the patients experience recurrent atrial arrhythmia.