Background — The risk of stroke from atrial flutter and its relationship with progression to atrial fibrillation (AF) is unclear. This study describes the incidence of AF and stroke in patients with atrial flutter, and whether atrial flutter ablation attenuates the incidence of AF and stroke.
Methods — We performed a population-based retrospective cohort study of adults with typical atrial flutter with no AF history. Using linked health administrative databases we defined three cohorts: 1. adult patients diagnosed with new isolated atrial flutter; 2. a contemporary, one-to-one matched, cohort from the Ontario population; 3. patients with isolated atrial flutter who underwent atrial flutter ablation.
Results — A total of 9,339 new typical atrial flutter patients were identified and 7,248 were matched to general population subjects. Over the three-year follow-up, AF occurred in 40.4% of patients with atrial flutter, and 3.3% of the matched general population (rate ratio 12.2; p<0.001). Stroke occurred in 4.1% of patients with atrial flutter and 1.2% of the general population cohort (rate ratio 3.4; p<0.001). Among 218 patients who had an atrial flutter ablation, atrial fibrillation occurred in 47 (21.6%) over the following 3 years, and incidence of stroke was between 0 and 2.3%.
Conclusions — Patients with isolated atrial flutter develop atrial fibrillation and stroke at a higher rate than the general population. Catheter ablation reduces but does not eliminate future AF incidence and stroke risk and continued anticoagulation after successful atrial flutter ablation may therefore be warranted.