A leadless ventricular pacemaker providing atrioventricular synchronous pacing in the real-world setting: results from the Micra AV post-approval registry

Abstract

Abstract Introduction Advances in leadless pacemaker technology have enabled accelerometer based atrioventricular synchronous (AVS) pacing by sensing atrial mechanical contraction. However, longer-term performance of these devices in real-world clinical practice has not been assessed. Objectives To report the performance of the Micra AV transcatheter pacemaker from the worldwide Micra AV post-approval registry (PAR) through 1-year post-implant. Methods The Micra AV PAR is an ongoing prospective single-arm observational study designed to assess the safety and effectiveness of the Micra AV system in the real-world setting. Patients enrolled in the Micra AV PAR will be followed for 3 years. For the present interim analysis, baseline characteristics, total AV synchrony index (sum of %AM-VP, %AM-VS, and AV conduction mode switch percentage), major complications, and system revisions through 12-months of implant were summarized and compared to a historical cohort of 2,667 transvenous dual chamber (TV-DC) pacing patients. Results The device was successfully implanted in 797 of 801 patients (99.4%) at 98 centers in 19 countries between February 2020 and April 2022. Mean age was 74.1±15.1 years, 42.2% were female, and 31.3% were precluded from transvenous device therapy. Micra AV patients were on average older (74.1 vs. 71.1 yrs, P<0.0001) and had a significantly higher incidence of renal disease (22.3% vs. 9.8%, P<0.0001) compared with TV-DC patients. Mean follow-up was 7.7±6.4 months. Through 12-months, the major complication rate was 4.2% in Micra AV patients compared to 8.8% TV-DC patients (HR: 0.48, P<0.001, Figure). At 12-months, the system revision rate was 1.9% in Micra AV patients compared to 5.5% for TV-DC patients (HR: 0.28, P<0.001). The reduction in system revisions was largely driven by the absence of lead dislodgements requiring revision. Of the 397 patients with device interrogation files available for analysis, 315 (79.4%) were programmed to VDD mode at last follow-up and had a median AV synchrony index of 86.4% (IQR: 68.8% - 97.4%). Conclusions The Micra AV leadless pacemaker was implanted with a high rate of success in patients with a high co-morbidity burden, with a significantly lower rate of complications and system revisions through 12-months compared to dual-chamber transvenous pacemakers despite patients being older and having a higher incidence of renal disease. Longer-term performance will continue to be assessed in this ongoing trial.Major Complications Through 12-months