Cardiac pacemaker (PM) implantation is the established treatment for relevant bradyarrhythmias. Conventional PMs require 1-3 pacing leads to register the heart's intrinsic activity ("sensing") and to deliver the electrical stimuli to the heart ("pacing"). These leads are responsible for the vast majority of morbidity after implantation and PM failures. Therefore, a leadless PM system (Micra TPS™, Medtronic, United States) has been introduced a few years ago. This system overcomes the limitations of leads, however, the first generation of the Micra TPS™ only allowed sensing and pacing in the right ventricle. More recently, an upgraded version has been introduced and gained market approval (Micra AV, Medtronic, United States). According to published results from several clinical trials, this device allows sensing the atrial activity and, thus, timing the delivery of the ventricular pacing impulse in a physiological manner similar to a conventional dual-chamber PM with two leads. Clinical feasibility and safety for this concept have been established already. However, it is unclear if this translates into a direct clinical benefit for patients in comparison to conventional PM systems. The aim of this trial is to compare the therapeutic efficacy of the Micra AV™ PM and conventional dual-chamber PM systems in patients with intermittent or permanent atrioventricular conduction block and a PM indication according to the latest European guidelines. Thus, patients will be randomized to either a conventional dual-chamber PM implantation or the implantation of a leadless Micra AV™ system. Patients will be stratified for gender (female/male) and a priori estimated physical exercise capacity ("fit"/"unfit"). The primary outcome will be the physical exercise capacity of the patients. The null hypothesis with regards to the primary endpoint is that the leadless pacemaker arm shows an inferior VO2 anaerobic threshold than the conventional pacemaker arm. Hence the alternative hypothesis postulates that the leadless pacemaker arm shows a non-inferior VO2 anaerobic threshold compared to the conventional pacemaker arm. Rejection of the null hypothesis is needed to conclude non-inferiority.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
100
Implantation of a conventional cardiac pacemaker
Implantation of a leadless cardiac pacemaker
Inselspital, Bern University Hospital
Bern, Switzerland
RECRUITINGExercise capacity
Exercise capacity (VO2 at anaerobic threshold) as assessed by spiroergometry
Time frame: Month 3 post implantation
Total implantation time
Total implantation time
Time frame: During implantation on day 0
Total fluoroscopy time
Total fluoroscopy time during implantation
Time frame: During implantation on day 0
Total fluoroscopy dosage
Total fluoroscopy dosage during implantation
Time frame: During implantation on day 0
Pacing thresholds
Pacing thresholds of the implanted pacemaker
Time frame: Days 0,1 and months 1,3,12 and 24 post implantation
Sensing values
Sensing values of the implanted pacemaker
Time frame: Days 0,1 and months 1,3,12 and 24 post implantation
Impedance values
Impedance values of the implanted pacemaker
Time frame: Days 0,1 and months 1,3,12 and 24 post implantation
Duration of exercise
Duration of exercise until exhaustion assessed by spiroergometry
Time frame: Month 3 post implantation
VO2max
VO2max assessed by spiroergometry
Time frame: Month 3 post implantation
VE/VCO2
VE/VCO2 assessed by spiroergometry
Time frame: Month 3 post implantation
VE/VO2
VE/VO2 assessed by spiroergometry
Time frame: Month 3 post implantation
Maximum atrial heart rate
Maximum atrial heart rate as assessed by spiroergometry
Time frame: Month 3 post implantation
Left ventricular ejection fraction (LVEF)
LVEF as assessed by echocardiography
Time frame: Day 0 and months 3, 12 and 24 post implantation
Degree of tricuspid valve regurgitation
Degree of tricuspid valve regurgitation assessed by trans-thoracic echocardiogram. The degree of tricuspid valve regurgitation will be classified as "none", "mild", "moderate" or "severe"
Time frame: Day 0 and months 3, 12 and 24 post implantation
Degree of mitral valve regurgitation
Degree of mitral valve regurgitation assessed by trans-thoracic echocardiogram. The degree of mitral valve regurgitation will be classified as "none", "mild", "moderate" or "severe"
Time frame: Day 0 and months 3, 12 and 24 post implantation
Quality of Life scores measured with the EQ-5D-5L Questionnaire
Quality of Life scores measured with the EQ-5D-5L Questionnaire Scores: mobility, self-care, usual activities, pain/discomfort and anxiety/depression, each with a 5-scale response option; current health state assessed with a number between 0 and 100
Time frame: Days 0,1 and months 1,3,12 and 24 post implantation
AV synchrony
Time frame: Day 1 and months 1,3,12 and 24 post implantation
Laboratory
NT-proBNP
Time frame: Day 0 and month 3 post implantation
Safety outcomes
Major adverse events (death, cardiac tamponade, any surgical reintervention, pocket/groin problems, lead/device dislocations; electrode noise, pacing impedance out of range (\<200 or \>2000Ω), failure to capture at maximum output, infections and thrombosis/embolism); rate of pacemaker syndrome developed by patients; rate of device upgrades/revisions required
Time frame: Days 0,1 and months 1,3,12 and 24 post implantation
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