First European experience with a leadless atrial pacemaker.

Background: Leadless pacemakers (LPs) can reduce long-term complications compared with conventional devices. However, previous studies have primarily focused on single chamber right ventricular LPs. Objective: This study aimed to evaluate the implantation, safety, and device performance characteristics in a first real-world European use of an active fixation atrial LP for either dual chamber or single chamber pacing. Methods: For this prospective, single-center, single-operator analysis, we included consecutive patients undergoing implantation of an active fixation atrial LP either as a standalone therapy or as part of a dual chamber LP system. Results: Of the 45 included patients, 22 (48.9%) underwent de novo dual chamber, 9 (20%) an upgrade from ventricular single chamber to dual chamber, and 14 (31.1%) an atrial single chamber LP implantation. All implantations were successful and without the need for device repositioning. The median procedure time was 35 minutes (interquartile range 30-40), and complications occurred in 2 patients (4.4%) who developed pericardial effusions. Sensing, impedance, and stimulation thresholds of the atrial and ventricular device remained stable or improved over a median follow-up of 21 days. Median implant-to-implant throughput was 88% for atrial-to-ventricular and 87% for ventricular-to-atrial. The estimated median battery life of the atrial device was significantly higher in single chamber vs dual chamber settings (11.9 years vs 5.8 years, Conclusion: Our first real-world European experience demonstrates that leadless atrial pacemaker implantation can be performed efficiently and safely, with satisfactory device measurements during the early follow-up period.