Clinical- and Device-Related Factors Associated With Atrial High Rate Episodes in Patients With Dual-Chamber Pacemakers.

Introduction Atrial high-rate episodes (AHREs) detected by dual-chamber pacemakers may represent subclinical precursors of atrial fibrillation and thromboembolic events. However, the clinical-, electrocardiographic-, and device-related characteristics distinguishing patients with and without AHREs are not fully defined. This study aimed to compare these variables between both groups to identify those independently associated with the presence of AHREs. Methods This retrospective, single-center observational study included ambulatory patients with dual-chamber pacemakers evaluated between June and December 2024. Clinical, electrocardiographic, and device-related variables were compared between patients with and without AHREs. Bivariate analyses were conducted to identify significant differences, and multivariable logistic regression was used to determine variables independently associated with the presence of AHREs. Results A total of 450 individuals were included, of whom 185 (41.1%) exhibited AHREs, compared to 265 (58.9%) without AHREs, those affected were more frequently female, 116 (62.7%) versus 140 (52.8%), p = 0.037, and had a higher prevalence of prior atrial fibrillation or atrial tachycardia, 98 (53.0%) versus 68 (25.7%), p < 0.001. Ventricular pacing was slightly lower in the AHRE group (median 98% vs. 99%; p = 0.016), and atrial pacing mode with switch to dual-chamber (AAI-DDD) pacing mode was more common, 44 (23.8%) versus 32 (12.1%), p = 0.001. In multivariable analysis, prior atrial arrhythmias (OR 2.95; p < 0.001), follow-up ≥ 90 days (OR 4.14; p = 0.012), female sex (OR 1.63; p = 0.020), and AAI-DDD pacing (OR 1.92; p = 0.027) were independently associated with AHREs. The model demonstrated acceptable discrimination (area under the curve (AUC) = 0.70). Conclusion In this cohort, AHREs were observed in 41.1% of participants. Their occurrence was significantly associated with female sex, a prior history of atrial fibrillation or atrial tachycardia, a follow-up duration of 90 days or more, reduced ventricular pacing, and the use of the AAI-DDD pacing mode.