Atrial fibrillation and antithrombotic therapy in a 75-year-old population

Aims: To find the true prevalence of diagnosed and undiagnosed atrial fibrillation (AF) in a population aged 75 years in 2 municipalities in Norway, and to study the use of antithrombotic therapy in this group. Methods: All 1,117 citizens in Asker and Baerum municipalities in eastern Norway born in 1930 were invited to participate in a prevalence study of AF. Nine hundred and sixteen subjects (82%) were examined by electrocardiogram, and blood pressure and pulse rate were measured. Comorbidity and current medication were recorded. Results: AF was present in 92 subjects (10%; 95% CI 8.2-12.1%), including 33 with ECG-documented, paroxysmal AF. In addition, 8 subjects had a history of a single, transient episode of AF. AF was previously undiagnosed in 10 out of 916 (1.1%). In 77 of 82 patients with previously diagnosed AF (93.9%), antithrombotic therapy was compliant with international guidelines. Conclusion: Ten percent (95% CI 8.2-12.2%) in this 75-year-old population had AF. Compliance with international guidelines regarding antithrombotic therapy was high. Previously undiagnosed AF was found in only 10 out of 916 (1.1%).