Stroke Risk Highest in Paroxysmal Afib With Greater Burden of Afib

Adult patients with paroxysmal atrial fibrillation (AF) were shown to have the highest risk for stroke with a greater burden of AF, according to the results of a recent study published by JAMA Cardiology.

An extended continuous ambulatory electrocardiographic monitoring system was used to identify adults with paroxysmal AF noninvasively during a 14-day period. The groups were then monitored retroactively using medical records for ischemic stroke and other arterial thromboembolic events. The association of the burden of AF with thromboembolism while not taking anticoagulation medications was evaluated among groups. The burden of AF was defined as the percentage of analyzable wear time in AF or atrial flutter during the 14-day monitoring period.

Of the 25,268 adults monitored, 1965 had paroxysmal AF. The median burden of AF was 4.4%, and the median duration of the longest continuous episode of AF was 171 minutes. There were 29 thromboembolic events during the course of the study. Patients in the first and second quartile of AF burden had a 215% increase in the unadjusted risk for thromboembolic events while not taking anticoagulants. A secondary outcome of AF burden — the duration of the longest observed episode — was not significantly associated with thromboembolism while not taking anticoagulants.

Compared with the lower 2 tertiles of AF burden combined, the highest tertile (≥11.4%) was associated with a >3-fold higher adjusted rate of thromboembolism while not taking anticoagulation, even after adjusting for ATRIA (Anticoagulation and Risk Factors in Atrial Fibrillation) or CHA₂DS₂-VASc risk scores (adjusted hazard ratios, 3.13 and 3.16).

The authors noted the importance of this study, stating, “Characterizing the burden of [AF] in patients with paroxysmal [AF] could assist patients and physicians in having a more informed, shared decision-making discussion about stroke prevention strategies.”

Reference

Go AS, Reynolds K, Yang J, et al. Association of burden of atrial fibrillation with risk of ischemic stroke in adults with paroxysmal atrial fibrillation. The KP-RHYTHM study [published online May 16, 2018]. JAMA Cardiol. doi:10.1001/jamacardio.2018.1176