Introduction: Single atrial stimulation (AAI) has been commonly used for permanent pacing in sick sinus syndrome and significant bradycardia.
Objective: The study aimed to evaluate long‑term AAI pacing and to identify timing and reasons for pacing mode change.
Patients and methods: Retrospectively, we included 207 patients (60% women) with initial AAI pacing, who were followed‑up for an average of 12 years.
Results: At the time of death or loss to follow‑up, 71 patients (34.3%) had unchanged AAI pacing mode. The reason for an upgrade of the pacing system was development of atrial fibrillation (AF) in 43 patients (20.78%) and atrioventricular block (AVB) in 34 patients (16.4%). The cumulative ratio for a pacemaker upgrade reoperation reached 2.77 per 100 patient‑years of the follow‑up. Cumulative ventricular pacing below 10% after an upgrade to dual‑chamber pacemaker was observed in 28.6% of the patients. Younger age at implant was the leading independent predictor of the change to dual‑chamber simulation (hazard ratio, 1.98; 95% CI, 1.976-1.988; P = 0.001). There were 11 (5%) lead malfunctions that required reoperation. Subclavian vein occlusion was noted in 9 upgrade procedures (11%). One cardiac device-related infection was observed.
Conclusions: The reliability of AAI pacing decreases with each year of observation due to development of AF and AVB. However, in the current era of effective AF treatment, the advantages of AAI pacemakers, such as lower incidence of lead malfunction, venous occlusion, and infection, as compared with dual-chamber pacemakers, may make AAI pacemakers a viable option.