Detection of new atrial fibrillation in patients with cardiac implanted electronic devices and factors associated with transition to higher device-detected atrial fibrillation burden

Background: In patients with cardiac implanted electronic devices, detection of new atrial fibrillation (AF) is associated with an increased risk of stroke. Objective: To characterize daily AF burden at first detection and the rate of temporal transition to higher device-detected AF burden. Methods: A pooled analysis of data from 3 prospective projects was analyzed, and 6580 patients (mean age 68 ± 12 years, 72% male) with no history of AF and no use of anticoagulants at baseline were identified. Various thresholds of daily AF burden (5 minutes and 1, 6, 12, and 23 hours) were analyzed. Results: Among the study population of 6580 patients, a new AF, with an AF burden of ≥5 minutes, was detected in 2244 patients (34%) during a follow-up period of 2.4 ± 1.7 years. Among these patients, 1091 (49.8%) transitioned to a higher AF-burden threshold during follow-up. A higher duration of daily AF burden manifest at first detection and CHADS2 score ≥2 were associated with faster transition to a subsequent higher burden. Approximately 24% of patients transitioned from a lower threshold to a daily AF burden of ≥23 hours during follow-up. Conclusion: More than one-third of patients with no history of AF developed device-detected AF, with attainment of different thresholds of daily AF burden over time. Continuous long-term monitoring, especially when the initial detection corresponds to a higher daily AF burden and the CHADS2 score is ≥2, could support timely clinical decisions on anticoagulation by capturing transitions to higher AF-burden thresholds.