The natural history of lone atrial flutter

Background: The natural history of atrial flutter is not well defined. Objective: To report the risk for stroke, conversion to atrial fibrillation, and anticoagulation for lone atrial flutter. Design: Retrospective cohort analysis. Setting: A clinically based longitudinal study of inpatients and outpatients with atrial flutter. Patients: The authors compared the stroke rate in 59 patients with atrial flutter with rates in a sample in which age- and sex-specific ischemic cerebrovascular event rates were determined and in a sample of nonhypertensive patients with lone atrial fibrillation. The risk for developing atrial fibrillation after presenting with atrial flutter is also reported. Measurements: Electrocardiograms and clinical data were collected and reviewed for each study participant. Results: After adjustment for age and sex, patients with atrial flutter had a higher incidence of thromboembolic events than the sample control patients and patients with atrial fibrillation. Atrial fibrillation developed in 56% of patients with atrial flutter. Conclusions: Lone atrial flutter has a stroke risk at least as high as lone atrial fibrillation and carries a higher risk for subsequent development of atrial fibrillation than in the general population. Anticoagulation should be considered for all patients with atria[ flutter who are older than 65 years of age.