Development and validation of a risk score for predicting pericardial effusion in patients undergoing leadless pacemaker implantation: experience with the Micra transcatheter pacemaker

Leadless pacemaker implantation via the internal jugular vein

AIMS

Leadless pacemaker therapy was introduced to overcome lead- and pocket-related complications in conventional transvenous pacemaker systems. Implantation via the femoral vein, however, may not always be feasible. The aim of this study was to evaluate leadless pacemaker implantation using a jugular vein approach and compare it to the standard implantation via the femoral vein.

METHODS AND RESULTS

The records of the first consecutive 100 patients undergoing Micra™ leadless pacemaker implantation via the right internal jugular vein from two centres were included in this study. Peri-procedural safety and efficacy of the jugular approach were compared to the first 100 patients using a femoral implantation approach at the University Hospital Zurich. One hundred patients underwent successful implantation of a leadless pacemaker via the internal jugular vein (mean age, 81.18 ± 8.29, 60% males). Mean procedure time was 35.63 ± 10.29 min with a mean fluoroscopy time of 4.66 ± 5.16 min. The device was positioned at the inferior septum in 25 patients, at the high septum in 24 patients, and mid-septum in 51 patients. The mean pacing threshold was 0.56 ± 0.35 V at 0.24 ms pulse width with a sensed amplitude of 10.0 ± 4.4 mV. At follow-up, electrical parameters remained stable in all patients. Compared with femoral implantation, patients undergoing the jugular approach were of similar age and had similar comorbidities. Mean procedure (48.9 ± 21.0 min) and fluoroscopy times (7.7 ± 7.8 min, both P < 0.01) were shorter compared to the femoral approach. Electrical parameters were similar between the two approaches. There were only two complications during jugular veinous implantations (1 pericardial effusion and 1 dislocation), compared to 16 complications using the femoral approach (1 pericardial effusion, 2 femoral artery injuries, and 13 major groin haematomas).

CONCLUSION

The jugular approach may represent a safe and efficient alternative to femoral implantation of the Micra leadless pacemaker.

Leadless pacemaker implementation at the right atrial appendage apex: An initial preclinical assessment

OBJECTIVE

This study evaluates the feasibility and efficacy of implanting a leadless pacemaker at the right atrial appendage (RAA) in a preclinical minipig model, aiming to address the limitations of atrial pacing with current leadless devices like the Medtronic Micra, which is typically used for right ventricular implantation.

METHODS

Four minipigs, each with a median body weight of 45.8 ± 10.0 kg, underwent placement of the Micra transcatheter pacing system (TPS) via the right femoral vein into the RAA apex. The pacing performance was assessed over 1-week (short-term) and 3-month (long-term) periods.

OUTCOMES

The initial findings indicated successful implantation, with satisfactory intrinsic R-wave amplitudes and pacing threshold. In the following period, the sensitivity, threshold, and impedance were stable with time. Notably, upon explanation at 3 months, a deep myocardial penetration by the device was observed, necessitating a redesign for safe long-term use in a growing subject's heart.

CONCLUSION

While initial results suggest that RAA apex placement of the Micra TPS is promising for potential inclusion in a dual-chamber pacing system, the issue of myocardial penetration highlights the need for device redesign to ensure safety and effectiveness in long-term applications.

Recurrent Pericardial Effusion Resulting From Right Ventricular Free Wall Injury Caused by Leadless Pacemaker Tines

An 87-year-old man developed delayed cardiac tamponade 55 min after leadless pacemaker implantation and recurrent pericardial effusion 20 days later. Electrocardiogram-gated enhanced cardiac computed tomography revealed that the leadless pacemaker tines on the lateral side had penetrated the right ventricular free wall. He underwent off-pump hemostatic surgery.

Impact of omitting the intravenous heparin bolus on outcomes of leadless pacemaker implantation

BACKGROUND

Early guidance recommended a bolus of intravenous heparin at the beginning of leadless pacemaker (LP) implantation procedures. However, due to concern about bleeding complications, more recent practice has tended toward omitting the bolus and only running a continuous heparin infusion through the introducer sheath. The impact of omitting the heparin bolus on procedural outcomes is not clear.

METHODS

We reviewed all Medtronic Micra LP implants at our institution from 9/2014 to 9/2022. The decision to bolus with heparin was at operator discretion.

RESULTS

Among 621 LP implants, 326 received an intravenous heparin bolus, 243 did not, and 52 patients were excluded because heparin bolus status could not be confirmed. There was a trend toward more frequent omission of the heparin bolus with more recent implants. Median follow-up after LP implant was 14.3 (interquartile range [IQR]: 8.4-27.9) months. There was no difference between heparin bolus and no bolus groups in the number of device deployments/recaptures (1.42 ± 0.81 vs. 1.31 ± 0.66, p = .15). Implant-related adverse events were also similar between heparin bolus and no bolus groups: access-site hematoma requiring intervention (7 vs. 5, p = .99), pseudoaneurysm (1 vs. 1, p = .99), cardiac perforation (1 vs. 1, p = .99), intraprocedural device thrombus formation (2 vs. 4, p = .41), 30-day rehospitalization (21 vs. 15, p = .98), and 30-day all-cause mortality (16 vs. 14, p = .70). There was one additional nonfatal cardiac perforation in a patient who was excluded due to unknown heparin bolus status. Regarding device electrical parameters between heparin bolus and no bolus groups, there were no significant differences at the time of implant: pacing capture threshold 0.5 ± 0.4 vs. 0.5 ± 0.3, p = .10; pacing impedance 739.9 ± 226.4 vs. 719.1 ± 215.4, p = .52; R wave sensing 11.7 ± 5.7 vs. 12.0 ± 5.4, p = .34). Long-term device performance was also similar between groups.

CONCLUSION

Omission of the systemic heparin bolus at the time of LP implantation appears safe in appropriately selected patients. Heparin bolus may still be considered in long cases requiring multiple device deployments or in patients at high risk for thrombotic complications.

Revolutionizing Cardiology through Artificial Intelligence-Big Data from Proactive Prevention to Precise Diagnostics and Cutting-Edge Treatment-A Comprehensive Review of the Past 5 Years

BACKGROUND

Artificial intelligence (AI) can radically change almost every aspect of the human experience. In the medical field, there are numerous applications of AI and subsequently, in a relatively short time, significant progress has been made. Cardiology is not immune to this trend, this fact being supported by the exponential increase in the number of publications in which the algorithms play an important role in data analysis, pattern discovery, identification of anomalies, and therapeutic decision making. Furthermore, with technological development, there have appeared new models of machine learning (ML) and deep learning (DP) that are capable of exploring various applications of AI in cardiology, including areas such as prevention, cardiovascular imaging, electrophysiology, interventional cardiology, and many others. In this sense, the present article aims to provide a general vision of the current state of AI use in cardiology.

RESULTS

We identified and included a subset of 200 papers directly relevant to the current research covering a wide range of applications. Thus, this paper presents AI applications in cardiovascular imaging, arithmology, clinical or emergency cardiology, cardiovascular prevention, and interventional procedures in a summarized manner. Recent studies from the highly scientific literature demonstrate the feasibility and advantages of using AI in different branches of cardiology.

CONCLUSIONS

The integration of AI in cardiology offers promising perspectives for increasing accuracy by decreasing the error rate and increasing efficiency in cardiovascular practice. From predicting the risk of sudden death or the ability to respond to cardiac resynchronization therapy to the diagnosis of pulmonary embolism or the early detection of valvular diseases, AI algorithms have shown their potential to mitigate human error and provide feasible solutions. At the same time, limits imposed by the small samples studied are highlighted alongside the challenges presented by ethical implementation; these relate to legal implications regarding responsibility and decision making processes, ensuring patient confidentiality and data security. All these constitute future research directions that will allow the integration of AI in the progress of cardiology.

Leadless Pacemaker Implantation in Severe Kyphosis: Challenging Implantation for Tortuous IVC and Narrow RA

Leadless pacemaker implantation is recognized as safe and effective for treating bradycardia. However, there are limited descriptions of its use in patients with complex anatomical considerations. Here, we present a case detailing the successful implantation of a leadless pacemaker with a tortuous inferior vena cava and a narrow right atrium.

Leadless pacemakers at 5-year follow-up: the Micra transcatheter pacing system post-approval registry

BACKGROUND AND AIMS

Prior reports have demonstrated a favourable safety and efficacy profile of the Micra leadless pacemaker over mid-term follow-up; however, long-term outcomes in real-world clinical practice remain unknown. Updated performance of the Micra VR leadless pacemaker through five years from the worldwide post-approval registry (PAR) was assessed.

METHODS

All Micra PAR patients undergoing implant attempts were included. Endpoints included system- or procedure-related major complications and system revision rate for any cause through 60 months post-implant. Rates were compared through 36 months post-implant to a reference dataset of 2667 transvenous pacemaker patients using Fine-Gray competing risk models.

RESULTS

1809 patients were enrolled between July 2015 and March 2018 and underwent implant attempts from 179 centres in 23 countries with a median follow-up period of 51.1 months (IQR: 21.6-64.2). The major complication rate at 60 months was 4.5% [95% confidence interval (CI): 3.6%-5.5%] and was 4.1% at 36 months, which was significantly lower than the 8.5% rate observed for transvenous systems (HR: .47, 95% CI: .36-.61; P < .001). The all-cause system revision rate at 60 months was 4.9% (95% CI: 3.9%-6.1%). System revisions among Micra patients were mostly for device upgrades (41.2%) or elevated thresholds (30.6%). There were no Micra removals due to infection noted over the duration of follow-up. At 36 months, the system revision rate was significantly lower with Micra vs. transvenous systems (3.2% vs. 6.6%, P < .001).

CONCLUSIONS

Long-term outcomes with the Micra leadless pacemaker continue to demonstrate low rates of major complications and system revisions and an extremely low incidence of infection.

Pericardial effusion requiring intervention in patients undergoing leadless pacemaker implantation: A real-world analysis from the National Inpatient Sample database

Background

Pericardial effusion requiring percutaneous or surgical-based intervention remains an important complication of a leadless pacemaker implantation.

Objective

The study sought to determine real-world prevalence, risk factors, and associated outcomes of pericardial effusion requiring intervention in leadless pacemaker implantations.

Methods

The National Inpatient Sample and International Classification of Diseases-Tenth Revision codes were used to identify patients who underwent leadless pacemaker implantations during the years 2016 to 2020. The outcomes assessed in our study included prevalence of pericardial effusion requiring intervention, other procedural complications, and in-hospital outcomes. Predictors of pericardial effusion were also analyzed.

Results

Pericardial effusion requiring intervention occurred in a total of 325 (1.1%) leadless pacemaker implantations. Patient-level characteristics that predicted development of a serious pericardial effusion included >75 years of age (odds ratio [OR] 1.38, 95% confidence interval [CI] 1.08-1.75), female sex (OR 2.03, 95% CI 1.62-2.55), coagulopathy (OR 1.50, 95% CI 1.12-1.99), chronic pulmonary disease (OR 1.36, 95% CI 1.07-1.74), chronic kidney disease (OR 1.53, 95% CI 1.22-1.94), and connective tissue disorders (OR 2.98, 95% CI 2.02-4.39). Pericardial effusion requiring intervention was independently associated with mortality (OR 5.66, 95% CI 4.24-7.56), prolonged length of stay (OR 1.36, 95% CI 1.07-1.73), and increased cost of hospitalization (OR 2.49, 95% CI 1.92-3.21) after leadless pacemaker implantation.

Conclusion

In a large, contemporary, real-world cohort of leadless pacemaker implantations in the United States, the prevalence of pericardial effusion requiring intervention was 1.1%. Certain important patient-level characteristics predicted development of a significant pericardial effusion, and such effusions were associated with adverse outcomes after leadless pacemaker implantations.

Aveir VR real-world performance and chronic pacing threshold prediction using mapping and fixation electrical data

AIMS

Aveir VR performance and predictors for its pacing threshold (PCT) in a real-world cohort were investigated.

METHODS

Electrical measurements at various stages of an Aveir VR implant were prospectively collected. Predictors for 3-month PCT were studied. A retrospective cohort of consecutive 139 Micra implants was used to compare the PCT evolution. High PCT was defined as ≥1.5 V, using a pulse width of 0.4 ms for Aveir and 0.24 ms for Micra. Excellent PCT was defined as ≤0.5 V at the respective pulse width.

RESULTS

Among the 123 consecutive Aveir VR implant attempts, 122 (99.2%) were successful. The majority were of advanced age (mean 79.7) and small body size (mean BSA 1.60). Two patients (1.6%) experienced complications, including one pericardial effusion after device reposition and one intraoperative device dislodgement. Eighty-eight patients reached a 3-month follow-up. Aveir 3-month PCT was correlated with impedance at mapping (P = 0.015), tether mode (P < 0.001), end-of-procedure (P < 0.001), and mapping PCT (P = 0.035), but not with PCTs after fixation (P > 0.05). Tether mode impedance >470 ohms had 88% sensitivity and 71% specificity in predicting excellent 3-month PCT. Although it is more common for Aveir to have high PCT at end of procedure (11.5% for Aveir and 2.2% for Micra, P = 0.004), the rate at 3 months was similar (2.3% for Aveir and 3.1% for Micra, P = 1.000).

CONCLUSION

Aveir VR demonstrated satisfactory performance in this high-risk cohort. Pacing thresholds tend to improve to a greater extent than Micra after implantation. The PCT after fixation, even after a waiting period, has limited predictive value for the chronic threshold. Low-mapping PCT and high intraoperative impedance predict chronic low PCT.

Late cardiac tamponade after a helix-based active fixation leadless pacemaker implantation

Although the late cardiac tamponade in leadless pacemaker implantation (LPI) is rare, we encountered such an incident in patient with AVEIR-VR™ system on hemodialysis and warfarinization. When LPI with active fixation system, we should aim for successful single-attempt deployment using electrical premapping to prevent cardiac tamponade including the late phase.

Outcomes of patients implanted with an atrioventricular synchronous leadless ventricular pacemaker in the Medicare population

BACKGROUND

The Micra AV Coverage with Evidence Development study is a novel analysis of utilization and outcomes associated with Micra AV leadless pacing in US Medicare patients.

OBJECTIVE

The purpose of this study was to describe patient characteristics, complications, and outcomes of patients implanted with a Micra AV leadless pacemaker compared with a contemporaneous cohort of patients implanted with a dual chamber transvenous pacemaker.

METHODS

Patients implanted with Micra AV (n = 7471) or a dual chamber transvenous pacemaker (n = 107,800) from February 5, 2020, through December 1, 2021, were identified using device registry-linked Medicare claims data. Acute complications were assessed at 30 days, and chronic complications, reinterventions, and all-cause mortality were assessed at 6 months.

RESULTS

Patients implanted with Micra AV had higher rates of end-stage renal disease (14.9% vs 2.0%; P < .0001) and overall comorbidity burden (mean Charlson Comorbidity Index 4.9 vs 3.8; P < .0001). There was no difference in the unadjusted rate of complications at 30 days (9.1% vs 8.7%; P = .61), and patients implanted with Micra AV had a significantly lower adjusted rate of complications (8.6% vs 11.0%; P < .0001). At 6 months, patients implanted with Micra AV had significantly lower rates of complications (adjusted hazard ratio 0.50; 95% confidence interval 0.43-0.57; P < .0001) and reinterventions (adjusted hazard ratio 0.46; 95% confidence interval 0.36-0.58; P < .0001). Patients implanted with Micra AV had higher all-cause mortality at 30 days and 6 months, likely because of differences in the underlying risk of mortality.

CONCLUSION

Patients implanted with Micra AV had similar rates of complications at 30 days and significantly lower rates of complications and reinterventions at 6 months, despite being sicker than patients implanted with a transvenous pacemaker.

Safety and Performance of the Micra VR Leadless Pacemaker in a Japanese Cohort - Comparison With Global Studies

BACKGROUND

The Micra leadless pacemaker has demonstrated favorable outcomes in global trials, but its real-world performance and safety in a Japan-specific population is unknown.Methods and Results: Micra Acute Performance (MAP) Japan enrolled 300 patients undergoing Micra VR leadless pacemaker implantation in 15 centers. The primary endpoint was the acute (30-day) major complication rate. The 30-day and 6-month major complication rates were compared to global Micra studies. All patients underwent successful implantation with an average follow-up of 7.23±2.83 months. Compared with previous Micra studies, Japanese patients were older, smaller, more frequently female, and had a higher pericardial effusion risk score. 11 acute major complications were reported in 10 patients for an acute complication rate of 3.33% (95% confidence interval: 1.61-6.04%), which was in line with global Micra trials. Pericardial effusion occurred in 4 patients (1.33%; 3 major, 1 minor). No procedure or device-related deaths occurred. Frailty significantly improved from baseline to follow-up as assessed by Japan Cardiovascular Health Study criteria.

CONCLUSIONS

In a Japanese cohort, implantation of the Micra leadless pacemaker had a high success rate and low major complication rate. Despite the Japan cohort being older, smaller, and at higher risk, the safety and performance was in line with global Micra trials.

A Primer on Pacemakers and Defibrillators for Nurses

Although the concepts of pacing have been around for more than half a century, technological advances in cardiac implantable electronic devices (CIEDs) have changed the landscape for patients in need of pacing support or sudden death prevention. Nurses encounter patients with CIEDs in all aspects of the health care setting. Because exciting CIED therapies are on the horizon, nurses must stay up-to-date to promote optimal outcomes for CIED patients. This essential guide provides nurses with a comprehensive overview of the principles of pacing and implantable cardioverter defibrillators (ICDs), as well as innovative technologies such as leadless cardiac pacemakers and subcutaneous ICDs.

Preclinical cardiac perforation reduction in leadless pacing: An update to the Micra leadless pacemaker delivery system

BACKGROUND

Leadless pacemakers have been developed to avoid some of the complications that are associated transvenous pacemakers. Pericardial effusion is a rare complication of leadless pacemaker implantation, which may result from perforation of the delivery catheter. In this study, we describe preclinical perforation performance of an updated Micra delivery catheter.

METHODS

To assess preclinical perforation performance of the updated delivery catheter, three analyses were performed. First, Finite Element Analysis (FEA) computational modeling was performed to estimate the target tissue stress during Micra delivery catheter tenting. Second, benchtop perforation forces of ovine tissue were recorded for the original and updated delivery catheters. Finally, a Monte-Carlo simulation combining human cadaveric Micra implant forces and human ventricular tissue perforation properties was performed to estimate clinical perforation performance.

RESULTS

FEA modeling demonstrated a 66% reduction in target tissue stress when using the updated Micra delivery catheter (6.2 vs. 2.2 psi, Original vs. Updated Micra delivery catheter). Updated Micra delivery catheters required 20% more force to perforate porcine ventricular tissues in benchtop testing (μupd  = 26.9N vs. μorg  = 22.4N, p = .01). Monte-Carlo Simulation of catheter performance in human cadaveric tissues predicts 28.5% reduction of catheter-perforated cases with the updated delivery catheter.

CONCLUSIONS

This study, using computer modelling and benchtop experimentation, has indicated that increased surface area and rounding of the updated Micra catheter tip significantly improves preclinical perforation performance. It will be important to evaluate the impact of these catheter design changes with robust registry data.

Cardiac pacing and lead devices management: 25 years of research at EP Europace journal

AIMS

Cardiac pacing represents a key element in the field of electrophysiology and the treatment of conduction diseases. Since the first issue published in 1999, EP Europace has significantly contributed to the development and dissemination of the research in this area.

METHODS

In the last 25 years, there has been a continuous improvement of technologies and a great expansion of clinical indications making the field of cardiac pacing a fertile ground for research still today. Pacemaker technology has rapidly evolved, from the first external devices with limited longevity, passing through conventional transvenous pacemakers to leadless devices. Constant innovations in pacemaker size, longevity, pacing mode, algorithms, and remote monitoring highlight that the fascinating and exciting journey of cardiac pacing is not over yet.

CONCLUSION

The aim of the present review is to provide the current 'state of the art' on cardiac pacing highlighting the most important contributions from the Journal in the field.

Anatomic, histologic, and mechanical features of the right atrium: implications for leadless atrial pacemaker implantation

BACKGROUND

Leadless pacemakers (LPs) may mitigate the risk of lead failure and pocket infection related to conventional transvenous pacemakers. Atrial LPs are currently being investigated. However, the optimal and safest implant site is not known.

OBJECTIVES

We aimed to evaluate the right atrial (RA) anatomy and the adjacent structures using complementary analytic models [gross anatomy, cardiac magnetic resonance imaging (MRI), and computer simulation], to identify the optimal safest location to implant an atrial LP human.

METHODS AND RESULTS

Wall thickness and anatomic relationships of the RA were studied in 45 formalin-preserved human hearts. In vivo RA anatomy was assessed in 100 cardiac MRI scans. Finally, 3D collision modelling was undertaken assessing for mechanical device interaction. Three potential locations for an atrial LP were identified; the right atrial appendage (RAA) base, apex, and RA lateral wall. The RAA base had a wall thickness of 2.7 ± 1.6 mm, with a low incidence of collision in virtual implants. The anteromedial recess of the RAA apex had a wall thickness of only 1.3 ± 0.4 mm and minimal interaction in the collision modelling. The RA lateral wall thickness was 2.6 ± 0.9 mm but is in close proximity to the phrenic nerve and sinoatrial artery.

CONCLUSIONS

Based on anatomical review and 3D modelling, the best compromise for an atrial LP implantation may be the RAA base (low incidence of collision, relatively thick myocardial tissue, and without proximity to relevant epicardial structures); the anteromedial recess of the RAA apex and lateral wall are alternate sites. The mid-RAA, RA/superior vena cava junction, and septum appear to be sub-optimal fixation locations.

Peri-Procedural Management of Direct-Acting Oral Anticoagulants (DOACs) in Transcatheter Miniaturized Leadless Pacemaker Implantation

INTRODUCTION

Data on peri-operative management of direct-acting oral anticoagulants (DOACs) during transcatheter pacing leadless system (TPS) implantations remain limited. This study aimed to evaluate a standardized DOAC management regime consisting of interruption of a single dose prior to implantation and reinitiation within 6-24 h; also, patient clinical characteristics associated with this approach were identified.

METHOD

Consecutive patients undergoing standard TPS implantation procedures from two Swiss tertiary centers were included. DOAC peri-operative management included the standardized approach (Group 1A) or other approaches (Group 1B).

RESULTS

Three hundred and ninety-two pts (mean age 81.4 ± 7.3 years, 66.3% male, left ventricular ejection fraction 55.5 ± 9.6%) underwent TPS implantation. Two hundred and eighty-two pts (71.9%) were under anticoagulation therapy; 192 pts were treated with DOAC; 90 pts were under vitamin-K antagonist. Patients treated with DOAC less often had structural heart disease, diabetes mellitus, and advanced renal failure. The rate of major peri-procedural complications did not differ between groups 1A (n = 115) and 1B (n = 77) (2.6% and 3.8%, p = 0.685). Compared to 1B, 1A patients were implanted with TPS for slow ventricular rate atrial fibrillation (AF) (p = 0.002), in a better overall clinical status, and implanted electively (<0.001).

CONCLUSIONS

Standardized peri-procedural DOAC management was more often implemented for elective TPS procedures and did not seem to increase bleeding or thromboembolic adverse events.

Atrioventricular synchronous leadless pacing: Micra AV

Since the arrival of leadless pacemakers (LPs), they have become a cornerstone in remedial treatment of bradycardia and atrioventricular (AV) conduction disorders, as an alternative to transvenous pacemakers. Even though clinical trials and case reports show indisputable benefits of LP therapy, they also bring some doubts. Together with the positive results of the MARVEL trials, AV synchronization has become widely available in LPs, presenting a significant development in leadless technology. This review presents the Micra AV (MAV), describes major clinical trials, and introduces the basics of AV synchronicity obtained with the MAV and its unique programming options.

Leadless Pacing: Therapy, Challenges and Novelties

Leadless pacing is a rapidly growing field. Initially designed to provide right ventricular pacing for those who were contraindicated for conventional devices, the technology is growing to explore the potential benefit of avoiding long-term transvenous leads in any patient who requires pacing. In this review, we first examine the safety and performance of leadless pacing devices. We then review the evidence for their use in special populations, such as patients with high risk of device infection, patients on haemodialysis, and patients with vasovagal syncope who represent a younger population who may wish to avoid transvenous pacing. We also summarise the evidence for leadless cardiac resynchronisation therapy and conduction system pacing and discuss the challenges of managing issues, such as system revisions, end of battery life and extractions. Finally, we discuss future directions in the field, such as completely leadless cardiac resynchronisation therapy-defibrillator devices and whether leadless pacing has the potential to become a first-line therapy in the near future.

Strategies for Safe Implantation and Effective Performance of Single-Chamber and Dual-Chamber Leadless Pacemakers

Leadless pacemakers (LPMs) have emerged as an alternative to conventional transvenous pacemakers to eliminate the complications associated with leads and subcutaneous pockets. However, LPMs still present with complications, such as cardiac perforation, dislodgment, vascular complications, infection, and tricuspid valve regurgitation. Furthermore, the efficacy of the leadless VDD LPMs is influenced by the unachievable 100% atrioventricular synchrony. In this article, we review the available data on the strategy selection, including appropriate patient selection, procedure techniques, device design, and post-implant programming, to minimize the complication rate and maximize the efficacy, and we summarize the clinical settings in which a choice must be made between VVI LPMs, VDD LPMs, or conventional transvenous pacemakers. In addition, we provide an outlook for the technology for the realization of true dual-chamber leadless and battery-less pacemakers.

Leadless pacemaker implantation for pediatric patients through internal jugular vein approach: A case series of under 30 kg

BACKGROUND

We demonstrate a case series of 8 pediatric patients, all under 30 kg, who had leadless pacemaker implants via the internal jugular vein.

METHODS

A retrospective review of pediatric leadless pacing placement via the internal jugular vein at the University of Minnesota Masonic Children's Hospital and UC Davis Medical Center from 2018 through 2021 was performed. Rationales for pacing, demographics of patients, pacing thresholds, and longevity of devices were recorded.

RESULTS

Eight internal jugular pacemaker insertions were performed successfully in patients weighing between 10.9 kg and 29 kg. Five patients had Micra implantation via the right internal jugular vein, whereas 3 patients had insertion via the left internal jugular vein. No surgical cut-downs were performed. No venous complications occurred. Up to 3 years of follow-up were noted.

CONCLUSION

Leadless pacemaker implantation, via left or right internal jugular veins, is feasible without surgical cutdown in patients <30 kg.

Periprocedural anticoagulation therapy in patients undergoing micra leadless pacemaker implantation

Over the past decade, there has been significant improvement in the treatment cardiac diseases and symptomatic bradyarrhythmias with the development of leadless pacemaker systems. The Micra transcatheter pacemaker system has been shown to mitigate a lot of the complications associated with traditional pacing systems, which are notably skin pocket and lead-related complications. Numerous studies have shown the low complication rates associated with Micra procedure; however, there have been no specific guidelines or recommendations surrounding periprocedural anticoagulant therapy. This is important because a significant percentage of patients requiring pacemaker therapy have an indication for anticoagulation therapy as well. Multiple studies have shown the safety of uninterrupted anticoagulation during Micra implant, however, there is insufficient high-quality data to recommend periprocedural systemic use of anticoagulation. In this paper, we review the available data surrounding anticoagulation therapy in patients undergoing Micra implantation and the potential bleeding risks associated with this procedure.

A leadless pacemaker in the real-world setting: Patient profile and performance over time

Background

While prior Micra trials demonstrated a high implant success rate and favorable safety and efficacy results, changes in implant populations and safety over time is not well studied. The objective of this analysis was to report the performance of Micra in European and Middle Eastern patients and compare to the Micra Investigational Device Exemption (IDE) and Micra Post Approval Registry (PAR) studies.

Methods

The prospective, single-arm Micra Acute Performance European and Middle Eastern (MAP EMEA) registry was designed to further study the performance of Micra in patients from EMEA. The primary endpoint was to characterize acute (30-day) major complications. Electrical performance was analyzed. The major complication rate through 12 months was compared with the IDE and PAR studies.

Results

The MAP EMEA cohort (n = 928 patients) had an implant success rate of 99.9% and were followed for an average of 9.7 ± 6.5 months. Compared to prior studies, MAP EMEA patients were more likely to have undergone dialysis and have a condition which precluded the use of a transvenous pacemaker (p < .001). Within 30 days of implantation, the MAP EMEA cohort had a major complication rate of 2.59%. Mean pacing thresholds were low and stable through 12 months (0.61 ± 0.40 V at 0.24 ms at implant and 12 months). Through 12 months post-implantation, the major complication rate for MAP EMEA was not significantly different from IDE (p = .56) or PAR (p = .79).

Conclusion

Despite patient differences over time, the Micra leadless pacemaker was implanted with a high success rate and low complication rate, in-line with prior reports.

Ambulatory atrioventricular synchronous pacing over time using a leadless ventricular pacemaker: Primary results from the AccelAV study

BACKGROUND

Previous studies demonstrated that accelerometer-based, mechanically timed atrioventricular synchrony (AVS) is feasible using a leadless ventricular pacemaker.

OBJECTIVE

The purpose of this study was to determine the performance of a leadless ventricular pacemaker with accelerometer-based algorithms that provide AVS pacing.

METHODS

AccelAV was a prospective, single-arm study to characterize AVS in patients implanted with a Micra AV, which uses the device accelerometer to mechanically detect atrial contractions and promote VDD pacing. The primary objective was to characterize resting AVS at 1 month in patients with complete atrioventricular block (AVB) and normal sinus function.

RESULTS

A total of 152 patients (age 77 ± 11 years; 48% female) from 20 centers were enrolled and implanted with a leadless pacemaker. Among patients with normal sinus function and complete AVB (n = 54), mean resting AVS was 85.4% at 1 month, and ambulatory AVS was 74.8%. In the subset of patients (n = 20) with programming optimization, mean ambulatory AVS was 82.6%, representing a 10.5% improvement (P <.001). Quality of life as measured by the EQ-5D-3L (EuroQol Five-Dimensions Three-Level questionnaire) improved significantly from preimplant to 3 months (P = .031). In 37 patients with AVB at both 1 and 3 months, mean AVS during rest did not differ (86.1% vs 84.1%; P = .43). There were no upgrades to dual-chamber devices or cardiac resynchronization therapy through 3 months.

CONCLUSION

Accelerometer-based mechanical atrial sensing provided by a leadless pacemaker implanted in the right ventricle significantly improves quality of life in a select cohort of patients with AV block and normal sinus function. AVS remained stable through 3 months, and there were no system upgrades to dual-chamber pacemakers.

Clinical outcomes and predictors of complications in patients undergoing leadless pacemaker implantation

BACKGROUND

Leadless pacemakers have emerged as a viable alternative for traditional transvenous pacemakers to reduce the risk of device-related complications.

OBJECTIVE

The purpose of this study was to examine the real-world clinical outcomes and complications associated with the implantation of leadless pacemaker devices.

METHODS

Using the National Readmission Database (NRD), we examined patient demographics, and in-hospital and 30-day procedural outcomes after leadless pacemaker implantation from 2016-2018. Our cohort comprised adults (≥18 years) with an ICD-10 procedural code for leadless pacemaker implantation.

RESULTS

Our cohort included a total of 7821 patients who underwent leadless pacemaker implantation. Overall immediate procedure-related complications, as defined broadly in this study, occurred in 7.5% of patients. Pericardial effusion without the need for pericardiocentesis occurred in 1.9% of patients, with pericardiocentesis performed in 1.0%. Vascular complications occurred in 2.3% of patients; 0.33% required repair, and device dislodgment occurred in 0.51%. The most significant predictor for procedural complications was end-stage renal disease (odds ratio [OR] 1.65; 95% confidence interval [CI] 1.17-2.32; P = .004), congestive heart failure (OR 1.28; 95% CI 1.01-1.62; P = .04), and coagulopathy (OR 1.77; 95% CI 1.34-2.34; P <.001). All-cause readmission occurred in 17.9% of patients within 30 days from device implant, with 1.36% of readmissions being procedure related. At 30 days postimplant and after discharge, 0.25% of patients needed a new pacemaker, and 0.18% had pericardial complications.

CONCLUSION

In our large real-life cohort, we found the rate of serious complications after leadless pacemaker implantation to be relatively low and comparable to prior studies in a high-risk population with multiple comorbid conditions.