Pacemaker-detected atrial fibrillation burden and risk of ischemic stroke or thromboembolic events-A cohort study

Background: Atrial fibrillation (AF) burden might link to increased risk of systemic embolism. Current scoring systems for evaluating stroke risks such as CHA(2)DS(2)-VASc do not incorporate AF burden partly because of the difficulty to assess these data. Patients with dual-chamber pacemakers implanted have opportunities to acquire incidence and duration of AF. Objectives: We aimed to evaluate the AF burden and its association with thromboembolism in patients with dual-chamber pacemakers. Methods: This retrospective cohort study enrolled patients who underwent dual-chamber pacemaker implantation at our center between October 2003 and May 2017. We excluded patients with prior thromboembolism or receiving anticoagulants. The incidence and duration of pacemaker-detected AF were compared between patients with and without thromboembolic outcomes. Propensity score matching (1:1) was conducted based on clinical characteristics. Multivariate regressions were performed to determine the predictors of thromboembolic outcomes. Survival free from stroke and thromboembolism was assessed using Kaplan-Meier analysis in groups with different AF burden. Results: Among the 152 patients enrolled (43.4% women; age 73.2 +/- 13.3 years), ten experienced thromboembolic events within a median follow-up of 67 months. Patients with thromboembolisms had higher CHA(2)DS(2)-VASc scores but not higher AF burden. Higher CHA(2)DS(2)-VASc score was associated with increased risk for systemic thromboembolism [hazard ratio (HR), 1.87; 95% confidence interval (CI), 1.07-3.24; P = 0.027). In the propensity score-matched cohort with comparable CHA(2)DS(2)-VASc score, patients with thromboembolism had higher AF burden. Pacemaker-detected AF was associated with increased risk for thromboembolism (propensity-adjusted HR, 9.33; 95% Cl, 1.19-72.99; P = 0.033). Experiencing AF episodes lasting >6 min was a predictor of significantly higher risk of future stroke or thromboembolism (propensity-adjusted HR, 6.75; 95% CI, 1.30-35.11; P = 0.023). Conclusion: In patients with dual-chamber pacemakers and comparable CHA(2)DS(2)-VASc score, pacemaker-detected AF burden is associated with elevated risk for thromboembolism. Further research is needed to clarify how pacemaker-detected AF burden could incorporate with CHA(2)DS(2)-VASc score variables and help to guide anticoagulation. (C) 2019 Elsevier Inc. All rights reserved.