Atrial High‑rate Episodes and Risk of Major Adverse Cardiovascular Events in Patients with Dual Chamber Permanent Pacemakers: a Retrospective Study

Patients with atrial high-rate episodes (AHRE) are at higher risk of major adverse cardiovascular events (MACE). The cutoff threshold for AHRE duration for MACE, with/without history of atrial fibrillation (AF) or myocardial infarction (MI), is unknown. A total of 481 consecutive patients with/without history of AF or MI receiving dual-chamber pacemaker implantation were included. The primary outcome was a composite endpoint of MACE after AHRE ≥ 5 min, ≥ 6 h, and ≥ 24 h. AHRE was defined as > 175 bpm (MEDTRONIC) or > 200 bpm (BIOTRONIK) lasting ≥ 5 min. Cox regression analysis with time-dependent covariates was conducted. Patients' mean age was 75.3 ± 10.7 years and 188 (39.1%) developed AHRE ≥ 5 min, 115 (23.9%) ≥ 6 h, and 83 (17.3%) ≥ 24 h. During follow-up (median 39.9 ± 29.8 months), 92 MACE occurred (IR 5.749%/year, 95% CI 3.88-5.85). AHRE ≥ 5 min (HR 5.252, 95% CI 2.575-10.715, P < 0.001) and ≥ 6 h (HR 2.548, 95% CI 1.284-5.058, P = 0.007) was independently associated with MACE, but not AHRE ≥ 24 h. Patients with history of MI (IR 17.80%/year) had higher MACE incidence than those without (IR 3.77%/year, p = 0.001). Significant differences were found between MACE patients with/without history of AF in AHRE ≥ 5 min but not AHRE ≥ 6 h or ≥ 24 h. Patients with dual-chamber pacemakers who develop AHRE have increased risk of MACE, particularly after history of AF or MI.