Abstract
Introduction: Since beginning of cardiac pacing, implanters have been facing problems related to the weakest part of pacing system - pacing leads. Historically, there were problems with lead insulation or coating; another problem is lead or fixating helix fracture.1,2 Infection of cardiac implantable electronic devices (CIEDs) is also a significant issue.3,4 As a reaction to these challenges, the concept of leadless pacing was developed.
In this stimulation modality, miniature pacemaker is implanted directly into cavity of right ventricle, with fixation mechanism providing both stability and good electrode-myocardium contact.5,6 Originally, there were two systems designed, but only Micra (Medtronic, Inc.) is nowadays commercially available in the Czech Republic. Implantation is performed through femoral vein with long, steerable introducer.
Objective: To evaluate outcomes of implantation procedure of LP Micra (Medtronic, Inc.) in Institute of Clinical and Experimental Medicine, Prague, between 30th of March 2017 and 12th of November 2021. Methods: We implanted LP in 60 patients (mean age at implantation 73.7 years, SD +-9.9; 33.3% of patients were women).
Parameters of implantation procedure, such as implantation and fluoroscopy time, dose of x-ray radiation and occurrence of complications were evaluated. Stimulation parameters during implantation and after one month and one year were recorded.
Implantation procedure data were analyzed by Spear-man's test and bivariate analysis. Friedman's test was used for stimulation parameters analysis.
Results: Implantation procedure duration didn't change significantly (mean 63.5 min, SD +-27.5 min; Spear-man's p = -0.0575, p = 0.6624), but a significant decrease was observed in fluoroscopy time (mean 4.1 min, SD +-3.6 min; p = -0.4817, p <0.0001) and x-ray dose (mean 1 396.8 μGy/m2, SD +-3 248.6 μGy/m2; p = -0.6454, p <0.0001). During last 40 procedures, in 37 cases pacemaker implantation was successful in the first attempt and in three cases only one reposition of device was necessary.
Stimulation parameters (impedance, sensing, and pacing threshold) remained favorable after one month and one year after implant procedure. In total, 3 serious complications of procedure were observed (5%), all of them during the first 20 implantations.
In last 40 cases no serious complication was recorded. In the first year after LP Micra implantation 13 (21.7%) patients died.
Causal relation of any of deaths and implantation procedure wasn't demonstrated. Conclusion: Implantation of leadless pacemaker Micra is safe.
With increasing experience, procedure duration didn't change, but fluoroscopy time and x-ray radiation dose decreased. Stimulation parameters are favorable even after one year since implantation.
Mortality in the first year after implantation is relatively high, but is not related to the procedure.