Assessing safety of leadless pacemaker (MICRA) at various implantation sites and its impact on paced QRS in Indian population.

Background: In this study we report our experience in implanting MICRA TPS (transcatheter pacing system) at various RV sites; observing its safety, and impact on paced QRS in Indian population.

Material & Methods: 35 patients with MICRA TPS deployed from March 2017 to December 2019 at Army Hospital Research and Referral, New Delhi, at RVOT, apical septum and mid septum of RV were enrolled in the study. These patents were followed up and impact of implantation site, procedure related complications, change in pacing parameters, left ventricular ejection fraction and duration of paced QRS were monitored.

Results: Sick sinus syndrome was the commonest indication of pacing in this study (51.5%), followed by high degree AV block (34.2%). Mean follow up of 1.4 years showed no change in left ventricular ejection fraction, electrical parameters or change in pacing thresholds after implantation. Mean pQRS was broadest (166.60 ms) in apically implanted MICRA TPS and narrowest in mid septum group 139.33 ms. Among 35 cases, in our study one patient developed pericardial effusion, and other had intermittent diaphragmatic pacing.

Conclusion: Among these three implantation sites mid septum deployment is associated with narrowest paced QRS in Indian population.