Leadless Pacemakers - Implant, Explant and Long-Term Safety and Efficacy Data

Leadless Pacemaker Implantation in Patients With a Prior Conventional Pacing System

Background

Leadless pacing has been established as an alternative approach to transvenous devices for selected patients. Often, leadless pacemaker (LP) implantation is a de novo procedure, but in an increasing number of patients, an LP is used after previous implantation of a conventional pacing system (CPS).

Methods

A retrospective analysis was conducted of the efficacy and safety of LP implantation in the context of a previously implanted CPS, from 2 large Swiss centres.

Results

A total of 257 consecutive patients undergoing LP implantation were included. They were divided into 2 groups: group 1 consisted of 233 patients who did not have a previous CPS, and group 2 consisted of 24 patients with an in situ CPS. In group 2, a total of 20 patients (83%) required transvenous lead extraction due to infection, malfunction, or other reasons. In 3 patients with device-related infection, lead extraction and LP implantation was performed as a single procedure, whereas in the remaining 11 cases, a time window occurred between the 2 procedures (median: 11.5 days; range: 2-186 days). Electrical device parameters at implantation and during follow-up did not differ between the 2 groups (mean: 12.5 ± 9.3 months). Eight major periprocedural complications (3.1%) were encountered (4 pericardial effusions, 3 instances of femoral bleeding, and 1 instance of intra-abdominal bleeding) in the entire cohort within a 30-day period. No complications occurred in the group with a previous device. No infections were registered, even when complete extraction of an infected CPS was performed prior to LP implantation.

Conclusions

Implantation of an LP in patients with a prior CPS (with or without extraction of the previous system) was effective and safe in our population of patients.

Leadless Pacemaker Implantation, Focusing on Patients With Conduction System Disorders Post-Transcatheter Aortic Valve Replacement: A Retrospective Analysis

Background

Impairment of the conduction system is a common complication of transcatheter aortic valve replacement (TAVR), which is typically performed in elderly patients. A leadless pacemaker (LP) may be a suitable option in this frail population, but the available scientific data concerning the efficacy and safety of leadless pacing after TAVR are sparse. The purpose of this analysis was to evaluate the efficacy and safety of LP implantation in patients with relevant bradycardias after TAVR, compared to other indications.

Methods

Consecutive patients were retrospectively enrolled. Demographics, background heart diseases, interventional parameters, and follow-up data were collected.

Results

A total of 257 consecutive patients who underwent LP implantation were included. In 26 patients, the device was implanted due to bradycardias after TAVR (TAVR group), whereas the remaining 231 patients were in the population without previous TAVR (non-TAVR group). The mean implantation duration (56 ± 22 minutes in the TAVR group vs 48 ± 20 minutes in the non-TAVR group; P = not significant [NS]) and the implantation success rate (100% in the TAVR group vs 98.7% in the non-TAVR group; P = NS) were similar in the 2 cohorts. No significant differences occurred in pacing parameters (sensing, impedance, and threshold, respectively) between the 2 groups, either at implantation or during follow-up. A total of 8 major periprocedural complications (3.1% of patients in total; 3.8% in the TAVR group vs 3.0% in the non-TAVR group; P = NS) occurred within 30 days, without significant difference between the 2 groups.

Conclusions

LP implantation appears to be safe and effective in patients after TAVR, and therefore, this procedure is a suitable option for this often old and frail population.

Efficacy and Safety of Leadless Pacemaker Implantation in Octogenarians

INTRODUCTION

Long-term complication rates in standard transvenous pacemakers are reported around 4-12% with a higher incidence in the elderly population. We report our experience in octogenarians undergoing leadless pacemaker implantation in two large-volume centers in Switzerland.

METHODS

Consecutive patients undergoing leadless pacemaker implantation at two Swiss large volume centers (University Hospital Zurich, Zurich and Cardiocentro Ticino Institute, Lugano) between October 2015 and March 2020 were included in this retrospective analysis. Demographic information, clinical data, and procedural characteristics were recorded at the day of implantation and during follow-up.

RESULTS

Two hundred and twenty patients (mean age 80.6 ± 7.7 years, male 66%) were included. The main indication for pacemaker implantation was slow ventricular rate atrial fibrillation (111 of 220 patients, 50.4%). Out of the 220 patients, 124 (56.3%) were ≥80 years. Overall successful implantation rate was 98.6%. In the octogenarian population, the median procedure time (45 ± 20.2 min vs. 40 ± 19.6 min, p = 0.03) and radiation duration (6.1 ± 8.2 min vs. 5.0 ± 7.2 min, p = 0.03) were longer compared to patients <80 years. Major complications (2.7%, n = 6) and device measurements during follow-up were similar between patients ≥80 and <80 years.

CONCLUSION

Implantation of a leadless pacemaker device in octogenarians is safe and effective with a similarly low complication rate compared to non-octogenarians.

Leadless Pacemaker Implantation in the Emergency Bradyarrhythmia Setting: Results from a Multicenter European Registry

Background. Data on leadless pacemaker (LPM) implantation in an emergency setting are currently lacking. Objective. We aimed to investigate the feasibility of LPM implantation for emergency bradyarrhythmia, in patients referred for urgent PM implantation, in a large, multicenter, real-world cohort of LPM recipients. Methods. Two cohorts of LPM patients, stratified according to the LPM implantation scenario (patients admitted from the emergency department (ED+) vs. elective patients (ED−)) were retrieved from the iLEAPER registry. The primary outcome of the study was a comparison of the peri-procedural complications between the groups. The rates of peri-procedural characteristics (overall procedural and fluoroscopic duration) were deemed secondary outcomes. Results. A total of 1154 patients were enrolled in this project, with patients implanted due to an urgent bradyarrhythmia (ED+) representing 6.2% of the entire cohort. Slow atrial fibrillation and complete + advanced atrioventricular blocks were more frequent in the ED+ cohort (76.3% for ED+ vs. 49.7% for ED−, p = 0.025; 37.5% vs. 27.3%, p = 0.027, respectively). The overall procedural times were longer in the ED+ cohort (60 (45−80) mins vs. 50 (40−65) mins, p < 0.001), showing higher rates of temporary pacing (94.4% for ED+ vs. 28.9% for ED−, p < 0.001). Emergency LPM implantation was not correlated with an increase in the rate of major complications compared to the control group (6.9% ED+ vs. 4.2% ED−, p = 0.244). Conclusion. LPM implantation is a feasible procedure for the treatment of severe bradyarrhythmia in an urgent setting. Urgent LPM implantation was not correlated with an increase in the rate of major complications compared to the control group, but it was associated with longer procedural times.

Sheath shape pattern during leadless pacemaker implantation

PURPOSE

Options for shaping the delivery sheath of leadless pacemakers (LPs) based on the cardiac anatomy of patients are limited. We predicted the shape of the LP sheath during implantation using preoperative computed tomography (CT) and intraoperative fluoroscopy.

METHODS

Forty-eight patients with implanted LPs due to symptomatic bradyarrhythmia were divided into two groups, α-loop and non-α-loop, based on the shape of the LP delivery sheath head at implantation. Angles between the inferior vena cava (IVC) and the interventricular septum (IVST), and the IVC and right ventricular apex (RVA) were measured by CT. The relationship between the final sheath shape and position of the IVC and the right or left side of the line drawn vertically from the deflection point of the sheath in the LAO view on fluoroscopy was assessed.

RESULTS

Angles between the IVC and IVST (44.4 ± 5.9° vs. 50.2 ± 6.8°) and IVC and RVA (52.5 ± 5.3° vs. 58.8 ± 7.8°) on CT were significantly (p < 0.01) smaller in the α-loop group. To predict the α-loop shape, a combined IVC-IVST angle < 50° and IVC-RVA angle < 55° revealed higher sensitivity (81.8%). The delivery sheath positioned right of the vertical line was more frequent in the α-loop group (90.9% vs. 23.1%, p < 0.01).

CONCLUSIONS

When the preoperatively calculated angles of IVC to IVST and RVA on CT were narrow, the right side of the sheath in the IVC from the vertical line drawn from the deflection point in the LAO view indicated the need to shape the delivery sheath head into an α-loop during LP implantation.

Clinical outcomes of leadless pacemaker: a systematic review

INTRODUCTION

Transvenous pacemakers are associated with a significant amount of complications. Leadless pacemakers (LP) are emerging as an alternative to conventional devices. This article provides a systematic review of patient eligibility, safety and clinical outcomes of the LP devices.

EVIDENCE ACQUISITION

A systematic search for articles describing the use of LP was conducted. Out of two databases, 24 articles were included in the qualitative analysis. These articles comprised a total of 4739 patients, with follow-up times of 1-38 months. Further information was obtained from 10 more studies.

EVIDENCE SYNTHESIS

From a population of 4739 patients included in the qualitative analysis, 4670 LP were implanted with success (98.5%). A total of 248 complications were described (5.23%) during the follow-up. The most common were pacing issues such as elevated thresholds, dislodgements or battery failure (68 patients), events at the femoral access site such as hemorrhage, hematoma or pseudoaneurysms (64 patients) and procedure related cardiac injuries such as cardiac perforation, tamponade or pericardial effusion (47 patients). There were 360 deaths during the follow-up and 11 were described as procedure or device related. Four studies presented the strategy of using a combined approach of atrioventricular node ablation (AVNA) and LP implantation.

CONCLUSIONS

Leadless pacemakers seem to have a relatively low complication rate. These devices may be a good option in patients with an indication for single-chamber pacing, in patients with conditions precluding conventional transvenous pacemaker implantations. Studies directly comparing LP and transvenous pacemakers and data on longer follow-up periods are needed.

Safety of leadless pacemaker implantation in the very elderly

BACKGROUND

The Micra leadless pacemaker (MLP) has proven to be an effective alternative to a traditional transvenous pacemaker (TVP). However, there has been concern about using the MLP in frail elderly patients because of the size of the implant sheath and perceived risk of perforation.

OBJECTIVES

The objectives of this study were to report the safety of the MLP and compare MPLs with TVPs in the very elderly.

METHODS

All patients 85 years and older who received an MLP or a single-chamber TVP across 6 hospitals in the Northwell Health system from December 2015 to November 2019 were included. Demographic characteristics, procedural details, and procedure-related complications were reviewed.

RESULTS

Over 4 years, 564 patients underwent MLP implantation. During this time, 183 MLPs and 119 TVPs were implanted in patients 85 years and older. The mean age was 89.7 ± 3.4 years, and 47.4% were men. MLP implantation was successful in all but 3 patients (98.4% success rate). There was no difference in procedure-related complications (3.3% vs 5.9%; P = .276). Complications included 5 (2.7%) access site hematomas in the MLP group, 3 (2.5%) in the TVP group, 1 (0.5 vs 0.8%) pericardial effusion in each group, and 3 (2.5%) acute lead dislodgments (<24 hours) in the TVP group. MLP implantation resulted in a significantly shorter mean procedure time (35.7 ± 23.0 minutes vs 62.3 ± 31.5 minutes, P < .001).

CONCLUSION

In a large multicenter study of patients 85 years and older, MLP implantation (1) was successful in 98.4% of patients, (2) was safe with no difference in procedure-related complications compared to the TVP group, and (3) resulted in significantly shorter procedure times.

The feasibility of leadless pacemaker implantation for superelderly patients

BACKGROUND

The safety and efficacy of the leadless pacemaker (LP) have been confirmed in previous reports, yet studies on LPs in superelderly patients are limited.

METHODS AND RESULTS

A total of 62 patients aged over 85 years old were implanted with single-chamber pacemakers due to symptomatic bradyarrhythmia at Sakakibara Heart Institute from May 2014 through July 2019. We divided them into two groups, a transvenous (TV) single-chamber pacemaker group (35 patients) and an LP group (27 patients), and compared the groups. Mean participant age was 90.3 ± 3.8 y.o., 41.9% were male, and mean participant body mass index (BMI) was 21.3 kg/m² . The LP group contained a significantly larger proportion of patients with dementia than the TV group did (63% vs. 37.1%, P = .04). The complication-free rate tended to be lower in the LP group in spite of the higher frequency of dementia (88.6% vs. 92.6%, P = .68). At implantation, the pacing threshold was significantly higher in the LP group than in the TV group (1.30 ± 0.91 V vs. 0.71 ± 0.23 V, P < .01), but over the first 3 months after the operation the pacing threshold in the LP group gradually improved (0.82 ± 0.2 V vs. 1.05 ± 1.02 V, P = .16). The procedure time and time from operation to discharge were also shorter in the LP group.

CONCLUSIONS

LP implantation appears to be safe and is accordingly becoming the cornerstone for Japanese superelderly patients indicated for single-chamber pacemakers, even for those with small bodies and dementia. However, careful procedures and long follow-ups are needed until a greater volume of data is reported.

Fundamental Characterization of Conductive Intracardiac Communication for Leadless Multisite Pacemaker Systems

OBJECTIVE

A new generation of leadless cardiac pacemakers effectively overcomes the main limitations of conventional devices, but only offer single-chamber pacing, although dual-chamber or multisite pacing is highly desirable for most patients. The combination of several leadless pacemakers could facilitate a leadless multisite pacemaker but requires an energy-efficient wireless communication for device synchronization. This study investigates the characteristics of conductive intracardiac communication between leadless pacemakers to provide a basis for future designs of leadless multisite pacemaker systems.

METHODS

Signal propagation and impedance behavior of blood and heart tissue were examined by in vitro and in vivo measurements on domestic pig hearts and by finite-element simulations in the frequency range of 1 kHz to 1 MHz.

RESULTS

A better signal transmission was obtained for frequencies higher than 10 kHz. The influence of a variety of practical parameters on signal transmission could be identified. A larger distance between pacemakers increases signal attenuation. A better signal transmission is obtained through larger inter-electrode distances and a larger electrode surface area. Furthermore, the influence of pacemaker encapsulation and relative device orientation was assessed.

CONCLUSION

This study suggests that conductive intracardiac communication is well suited to be incorporated in leadless pacemakers. It potentially offers very low power consumption using low communication frequencies.

SIGNIFICANCE

The presented technique enables highly desired leadless multisite pacing in near future.

Management of cardiac implantable devices in patients undergoing radiotherapy

The delivery of radiotherapy to patients with a cardiac implantable electronic device (CIED) is not an infrequent event. Consideration of the potential issues for patients is an important part of their care. An overview of CIEDs is provided, including the potential problems encountered and the steps that can be taken to mitigate this risk.