One-year outcomes of the first 1000 patients implanted with MICra AV Leadless Pacemaker in France: Findings from the AV-CESAR Cohort Study.

The Micra AV leadless pacemaker offers atrioventricular (AV) synchronous pacing by sensing atrial mechanical contraction. However, outcomes have only been reported through 6 months from experienced centers in a limited number of patients. Real-world data are needed. The main outcomes were the overall and major complications rate, as well as the incidence of upgrade for transvenous dual-chamber pacemaker. Major complications were defined as death, requirement of intervention, pacemaker syndrome, system revision, loss of device function, or failure to achieve AV synchrony leading to a shift to VVI mode pacing. The AV-CESAR is a retrospective, multicenter nationwide single-arm observational study, designed to assess the Micra AV in the first 1000 patients in France (NCT05953558). The device was successfully implanted in 830 out of 837 patients included (99.2%). The mean age was 72.3 ± 14.9 years, with 37.3% females. A significant proportion of patients presented with multiple severe comorbidities, including congestive heart failure (50%), cancer (30%), and conditions precluding transvenous pacing (50%). The most common indication (79.3%) was complete AV block with preserved sinus node function. The mean ventricular pacing percentage was 55 ± 12%. The mean follow-up was 13.8 ± 5.2 months. The Kaplan–Meier estimate of the 12-month freedom from major complications was 89.0% (95% CI: 86.5–91.4%) (Fig. 1), with a 2.5% of early (pre-hospital discharge) major complications (1% of cardiac injuries, 0.8% of vascular issues, and 2 deaths related to the device) and 11.5% of late (post hospital discharge) major complications. Among them, 24 (2.9%) patients developed pacemaker syndrome, 11 (1.3%) experienced a delayed pacing threshold rise (>2 V @ 0.24 ms), 2 patients (0.2%) had early battery depletion (< 24 months), and 50 patients (6.1%) failed to achieve AV synchrony leading to a switch into VVI mode. A total of 18 (2.2%) patients received an alternative pacing system: 5 patients (0.6%) underwent dual-chamber pacemaker upgrade for pacemaker syndrome, 7 patients (1%) were upgraded for pacing-induced cardiomyopathy, and 6 patients (0.7%) underwent conventional pacemaker implant for device dysfunction. This first real-world large registry on AV Micra demonstrates good results of mid-term follow-up in patients with a high level of pacing requirement, especially in individuals with medical conditions precluding traditional dual chamber pacing. [ABSTRACT FROM AUTHOR]