Go AS, et al. - In adults with paroxysmal atrial fibrillation, researchers investigated whether the burden of atrial fibrillation described using noninvasive, continuous ambulatory monitoring is associated with ischemic stroke or arterial thromboembolism risk. Findings demonstrated a higher risk of ischemic stroke in relation to a greater burden of atrial fibrillation. This association was independent of known stroke risk factors.

Methods

• Researchers performed this retrospective cohort study from October 2011 to October 2016 at two large integrated health care delivery systems.
• They used an extended continuous cardiac monitoring system to find adults who had paroxysmal atrial fibrillation on 14-day continuous ambulatory electrocardiographic monitoring.
• The definition of burden of atrial fibrillation was the percentage of analyzable wear time in atrial fibrillation or flutter during the up to 14-day monitoring period.
• They used electronic medical records to identify ischemic stroke and other arterial thromboembolic events occurring while patients were not taking anticoagulation through November 2016 and used manual review for validation.
• After adjusting for the Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) or CHA₂DS₂-VASc stroke risk scores, they assessed the association of the burden of atrial fibrillation with thromboembolism while not taking anticoagulation.

Results

• This study included a total of 1,965 adults with paroxysmal atrial fibrillation, with a mean (SD) age of 69 (11.8) years.
• In this population, 880 (45%) were women, 496 (25%) were persons of color, the median ATRIA stroke risk score was 4 (interquartile range [IQR], 2-7), and the median CHA₂DS₂-VASc score was 3 (IQR, 1-4).
• As per data, the median burden of atrial fibrillation was 4.4% (IQR, 1.1%-17.23%).
• Patients with a higher burden of atrial fibrillation vs those who had a lower burden were less likely to be women or of Hispanic ethnicity, but had more prior cardioversion attempts.
• Findings demonstrated the association of the highest tertile of atrial fibrillation burden (≥ 11.4%) vs the combined lower two tertiles with a more than 3-fold higher adjusted rate of thromboembolism while not taking anticoagulants (adjusted hazard ratios, 3.13 [95% CI, 1.50-6.56] and 3.16 [95% CI, 1.51-6.62], respectively) after adjusting for either ATRIA or CHA₂DS₂-VASc stroke risk scores.
• Consistent results were observed across demographic and clinical subgroups.