Effect of Leadless Pacing on Heart Function

Ventricular Mechanical Impact, Contraction Efficiency and Heart Function With Right Ventricular Pacing by MICRATMTPS. Comparison With Conventional RV Pacing

This prospective, un-blinded, randomized, noninferiority, single centre study with 12 month follow-up included patients who were scheduled for a single-chamber PM implant. Patients were 1:1 randomized to undergo the implantation of a conventional VVI pacing system (Medtronic, Advisa ADSR03) with a ventricular pacing lead (Medtronic, 5076-58) in the right ventricle (called 'conventional group') or to be implanted with a leadless Micra TPS (called 'Micra group'). The primary objective was to assess and compare the mechanical impact of right ventricular pacing using the Micra TPS versus a conventional PM on the left ventricular function.

Our primary endpoint was to assess the mechanical impact of the Micra TPS on the left ventricular function. We measured the change of Global Longitudinal Strain over one year after pacemaker implantation. As secondary endpoint, we studied the effect of the Micra TPS on the right ventricle using speckle tracking for 2-D myocardial motion estimation. We also assesed conventionally the RV function using tricuspid annular plane systolic excursion (TAPSE) in accordance with the guidelines of the European Association of Cardiovascular Imaging and American Society of Echocardiography (6). Evolution of clinical and biological parameters as NYHA classification, '6 minutes 'walk distance and measurement of brain natriuretic peptide (NT-proBNP) test was also be performed at baseline and after one year follow-up. Design It was an interventional prospective not blinded randomized single center study. We will divide fifty patients into two groups (1:1 ratio) between May 2018 and December 2021: Group 1 : 25 patients underwent the implantation of a conventional VVI pacing system (Medtronic) with placement of a ventricular pacing lead Medtronic 5076-58 in the right ventricle. Group 2 : 25 patients underwent the implantation of a leadless pacing system MicraTM TPS. All implantation procedures were performed under local anaesthesia. To minimize the impact of the pacing site, we targeted as first position the RV mid septum. In the presence of inacceptable electrical measurements, an apical positioning was reached. All pacing positions were reviewed according to the Lieberman criteria. Patients follow-up We assured a minimal 1 year follow up post implantation. Patients were followed in the outpatient clinic at 1 month after implantation, 6 months and 12 months as in routine care. Two-dimensional echocardiography was performed 1 day before implantation and at each visit. A 6 minutes' walk distance will be performed at day 10 and at 1 year follow-up. As biological marker of the left ventricular function, brain natriuretic peptide (NT-proBNP) was also measured at baseline and at 1 year follow-up. Device data collections: We also recorded the implantation procedure times (from skin cut to closure) and the procedure fluoroscopy times. Follow-up of the electrical measurements was performed at the same time than the echocardiographic recording. All complications (implantation failure, device or lead dislodgements, implantation related infection, death) were also prospectively documented. Conventional 2D-Echocardiography: Transthoracic echocardiography was performed using a commercially available ultrasound machine (VividTM E95, GE Vingmed Ultrasound AS; Epiq, Philips Medical Systems). Baseline and follow-up echocardiographic examinations were performed using the same machine. Conventional echocardiographic data were analysed according to the recommendations of the European Association of Cardiovascular Imaging. Standard parasternal long- and short-axis and apical four and two-chamber and long axis view were acquired. Left ventricular end-diastolic volume (LVEDV), end-systolic volume (LVESV) and left ventricular ejection fraction were calculated using Simpson's rule in a four-chamber view. RV systolic function was evaluated by tricuspid annular plane systolic excursion (TAPSE) in a standard apical four-chamber view. Finally, valve function and particularly tricuspid function was assessed following the European recommendations. All echocardiographic values will be obtained from the average of measurements from six continuous normal cardiac beats. Ethical considerations: We followed the declaration of Helsinki regarding human experimentation. Moreover, the investigators respected national legislation regarding clinical research and confidentiality of the data obtained in this study. All the participants were informed about the aims and procedures of the study and signed an informed consent form before the inclusion in the study. The local ethical committees reviewed and approved this protocol.

24 patients underwent the implantation of a conventional VVI pacing system (Medtronic) with placement of a ventricular pacing lead Medtronic 5076-58 in the right ventricle.

Implantation of a leadless pacemaker type Micra TPS. Echocardiographic and clinical follow-up during 12 months

Implantation of a conventional monochamber pacemaker and right ventricular lead (Medtronic 5076-58)/ Echocardiographic and clinical follow-up during 12 months

Assessment and comparison of the mechanical impact of right ventricular pacing using the Micra TPS versus a conventional PM on the left ventricular function.

The primary endpoints were the change in left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS)

Measurment of electrical parameters: pacing thrshold, impedance and R-wave sensing. Measurment of percentage of ventricular pacing in both groups.

Inclusion Criteria: Patients with a Class I or II indication for single chamber pacemaker following international guidelines Exclusion Criteria: patients with previously implanted cardiac devices / mechanical valves that would interfere with the echocardiographic measurements patients with inadequate image quality at baseline that prohibited the assessment of myocardial mechanics using echocardiography patients with a left ventricular ejection fraction (LVEF) ≤40% at baseline patients considered to have a pre-existing condition challenging/precluding the implant of a conventional pacemaker patients who refused or were not able to provide written informed consent.