Association between change in maximum daily atrial fibrillation duration and ischemic stroke among patients with cardiac implantable electronic devices

Abstract Background Atrial fibrillation (AF) burden may impact ischemic stroke risk. However, AF is a dynamic disease, and patients experience variable burden over time due to natural changes to physiology or rhythm control interventions. Objectives To assess the association between changes in maximum daily AF duration (MDAFD) and ischemic stroke among patients with cardiac implantable electronic devices (CIEDs) capable of continuous AF detection. Methods The Optum® de-identified electronic health record (EHR) (2007-2021) was linked with the Medtronic CareLink® heart rhythm database for this study. CIED patients with healthcare activity recorded in the EHR >12 months pre- and >6 months post-CIED implant were included, excluding those with oral anticoagulation (OAC) prescription. MDAFD was assessed during the first 30 days post-implant (baseline period) and the 30 days prior to censoring. Associations between changes in MDAFD and ischemic stroke were evaluated, adjusting for CHA2DS2-VASc and chronic kidney disease. Results Of 26,400 patients (68±13 years; 60% male) analyzed, 2,544 (9.6%) had AF during baseline, and 664 patients (2.5%) suffered an ischemic stroke through 2.6±1.6 years of follow-up. Increased (vs. stable) MDAFD in follow-up was associated with a higher adjusted risk of ischemic stroke among patients with no AF at baseline. Among those with a baseline daily AF duration of 6 minutes-<1 hour, 1 hour-<5.5 hours, or 5.5 hours-<23.5 hours, there was no association between change in MDAFD, compared to stable MDAFD, and ischemic stroke. However, of those with a baseline MDAFD >23.5 hours, decreased MDAFD in follow-up was associated with a lower risk of ischemic stroke (Figure). Conclusions Incident AF is associated with an increased risk of ischemic stroke. In patients with high baseline MDAFD (>23.5 hours), decreased, compared to stable, AF duration in follow-up is associated with a lower risk of ischemic stroke. Accordingly, there may be threshold effects of baseline AF duration that benefit from enhanced rhythm control to reduce the incidence of ischemic stroke.Figure