Six-month Electrical Performance of the First Dual-Chamber Leadless Pacemaker

Background The first dual-chamber leadless pacemaker (DC-LP) system consists of two separate atrial and ventricular devices that communicate to maintain synchronous atrioventricular pacing and sensing. The initial safety and efficacy were previously reported. Objective Evaluate the chronic electrical performance of the DC-LP system. Methods Patients meeting standard dual-chamber pacing indications were enrolled and implanted with the DC-LP system (Aveir DR, Abbott), including right atrial and ventricular helix-fixation LPs (ALP, VLP). Pacing capture threshold, sensed amplitude, and pacing impedance were collected using the device programmer at prespecified time points from 0-6 months post-implant. Results De novo devices were successfully implanted in 381 patients with complete 6M data (62% male; age 69±14 years; weight 82±20 kg; 65% sinus node dysfunction, 30% AV block). ALPs were implanted predominantly in the right atrial appendage anterior base; VLPs primarily at the mid-to-apical right ventricular septum. From implant to 1 month, pacing capture thresholds (0.4 ms pulse width) improved in both ALPs (2.4±1.5 to 0.8±0.8 V, P<0.001) and VLPs (0.8±0.6 to 0.6±0.4 V, P<0.001). Sensed amplitudes improved in both ALPs (1.8±1.3 to 3.4±1.9 mV, P<0.001) and VLPs (8.8±4.0 to 11.7±4.2 mV, P<0.001). Impedances were stable in ALPs (334±68 to 329±52 Ω, P=0.17) and reduced in VLPs (789±351 to 646±190 Ω, P<0.001). Electrical measurements remained relatively stable from 1-6 months post-implant. No differences in electrical metrics were observed among ALP or VLP implant locations. Conclusion This first in-human evaluation of the new dual-chamber leadless pacemaker system demonstrated reliable electrical performance throughout the initial 6-month evaluation period.