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.