Safety and Performance of the Micra VR Leadless Pacemaker in a South Korean Cohort: A Comparison to Global Studies

Background and Objectives: The Micra leadless pacemaker demonstrated a favorable safety and efficacy profile in global trials, but its performance and safety in a South Korean-specific population are unknown. Methods: The prospective, single-arm Micra Acute Performance South Korean registry was designed to study the performance of the Micra VR leadless pacemaker in patients from South Korea. The primary objectives were to characterize the rate of acute (30 days) and longer-term (12 months) major complications. Electrical performance and quality of life at baseline and follow-up were also characterized. Results: A total of 100 enrolled patients underwent Micra VR implant at 8 centers in South Korea between July 2021 and February 2022 with 99% successfully implanted. Mean pacing capture threshold was 0.57±0.46 V at implant and remained stable through 12 months (0.65±0.44 V). Korean valuation of health status significantly increased from baseline (0.78±0.24) to 12 months (0.84±0.21) (p=0.016). Compared with global patients, South Korean patients were younger, had a lower body mass index, and fewer had a prior cardiovascular implantable electronic device (all p<0.01). During the follow-up period 1 major complication was reported (implant site hematoma) at 26 days post-implant. No pericardial effusion or tamponade events were observed. Through 12 months post-implant the major complication rate was 1.0% (95% confidence interval, 0.03%, 5.45%). Conclusions: In a South Korean cohort, the Micra VR leadless pacemaker was implanted with a high success rate and low major complication rate.