Abstract
Background: Data directly comparing the atrioventricular (AV)-synchronous leadless pacemaker (MicraAV) with a dual-chamber transvenous pacemaker (DDD) after transcatheter aortic valve replacement (TAVR) remain limited. Methods: We retrospectively studied patients undergoing pacemaker implantation for advanced or complete AV block within one month after TAVR at a single Japanese center between 2016 and 2025. After exclusions, the primary cohort comprised 74 patients (MicraAV, n = 29; DDD, n = 45). Clinical outcomes were assessed through 12 months, with death treated as a competing event for nonfatal outcomes. Device and echocardiographic parameters were evaluated longitudinally. Results: MicraAV recipients were less frequently female than DDD recipients (48.3% vs. 75.6%, p = 0.025). In the MicraAV and DDD groups, respectively, all-cause mortality was 6.9% and 6.7% (unadjusted HR, 1.12; 95% CI, 0.19–6.68; p = 0.904), heart failure rehospitalization occurred in 17.2% and 4.4% (subdistribution HR, 4.44; 95% CI, 0.86–22.92; p = 0.075), and device-related complications occurred in 6.9% and 4.4% (subdistribution HR, 1.60; 95% CI, 0.23–11.40; p = 0.636). The median MicraAV tracking index was 88.4% [IQR, 66.4–95.1]. No significant group-by-time interactions were observed for device electrical performance or echocardiographic left ventricular parameters. Tricuspid regurgitation worsened over time in the MicraAV group. Conclusions: All-cause mortality and device-related complications were infrequent in both groups, whereas heart failure rehospitalization occurred more frequently in the MicraAV group. Given the small number of events and wide confidence intervals, these findings should be considered exploratory and require confirmation in larger contemporary cohorts.