Prevalence of atrial fibrillation in the 65 or over Polish population. Report of cross-sectional NOMED-AF study.

BACKGROUND: Atrial fibrillation (AF) is the most common cardiac arrhythmia, characterized by an increased risk of thromboembolic complications that can be markedly reduced with anticoagulation. There is a paucity of studies assessing the total prevalence of AF in national populations. AIMS: To assess the nationwide prevalence of AF in a population of adults ≥65 old and to determine the impact of duration of electrocardiogram (ECG) monitoring on the number of newly detected AF episodes. METHODS: The NOMED-AF study (ClinicalTrials.gov; NCT: 0324347) was a cross-sectional study performed on a nationally representative random sample of 3014 Polish citizens 65 years or older. Final estimates were adjusted to the national population. All participants underwent up to 30 days of continuous ECG monitoring. Total AF prevalence was diagnosed based on the patient's medical records or the presence of AF in ECG monitoring. RESULTS: The prevalence of AF in the Polish population ≥65 years was estimated as 19.2% (95% confidence interval [CI], 17.9%-20.6%). This included 4.1% (95% CI, 3.5%-4.8%) newly diagnosed cases and 15.1% (95% CI, 13.9%-16.3%) previously diagnosed cases and consisted of 10.8% (95% CI, 9.8%-11.9%) paroxysmal AF and 8.4% (95% CI, 7.5%-9.4%) persistent/permanent AF. The incidence of all paroxysmal AF events as a function of ECG monitoring duration increased from 1.9% (95% CI, 1.4%-2.6%) at 24 hours to 6.2% (95% CI, 5.3%-7.2%) at 4 weeks. CONCLUSIONS: The prevalence of AF in elderly adults is higher than estimated based on medical records only. Four weeks of monitoring compared to 24-hour ECG Holter allow detection of 7-fold more cases of previously undiagnosed paroxysmal AF.