Use of leadless pacemakers in Europe: results of the European Heart Rhythm Association survey

Electrocardiographic predictors of atrial mechanical sensing in leadless pacemakers

BACKGROUND

Leadless pacemakers (LPs) capable of VDD pacing allow for atrioventricular synchrony through mechanical sensing of atrial contraction. However, mechanical sensing is less reliable and less predictable than electrical sensing.

OBJECTIVE

The purpose of this study was to evaluate P-wave amplitude during sinus rhythm from preoperative 12-lead electrocardiograms (ECGs) as a predictor for atrial mechanical sensing in patients undergoing VDD LP implantation.

METHODS

Consecutive patients undergoing VDD LP implantation were included in this 2-center prospective cohort study. ECG parameters were evaluated separately and in combination for association with the signal amplitude of atrial mechanical contraction (A4).

RESULTS

Eighty patients (median age 82 years; female 55%; mean body mass index [BMI] 25.8 kg/m2) were included in the study and 61 patients in the A4 signal analysis (19 patients in VVI mode during follow-up). Absolute (aVL, aVF, V1, V2) and BMI-adjusted (I, II, aVL, aVF, aVR, V1, V2) P-wave amplitudes from baseline ECGs demonstrated a statistically significant positive correlation with A4 signal amplitude (all P <.05). A combined P-wave signal amplitude of at least 0.2 mV in V1 and aVL was predictive, with specificity of 83% (95% confidence interval 67%-100%) for A4 signal ≥1 m/s2. We found a significant correlation of A4 signal amplitude and overall atrioventricular synchrony (P = .013).

CONCLUSION

P-wave amplitudes in ECG leads aVL and V1 can predict A4 signal amplitude in patients with VDD LP and therefore the probability of successful AV synchronous pacing.

Systematic review of leadless pacemaker

Conventional pacing systems consist of a pacemaker and one or more leads threaded from the device pocket through veins into the heart conducting the pacing therapy to the desired pacing site. Although these devices are effective, approximately one in eight patients treated with these traditional pacing systems experiences a complication attributed to the pacemaker pocket or leads. With the technological advances in electronics, leadless pacemakers that small enough to implant within the heart were introduced. Leadless pacemakers have been developed to overcome many of the challenges of transvenous pacing including complications related to leads or pacemaker pockets. This review aims to provide an overview of advantages of leadless pacemaker, complications and limitations of leadless pacemaker, leadless pacemaker candidate, and future directions of this promising technology.

Harnessing cell reprogramming for cardiac biological pacing

Electrical impulses from cardiac pacemaker cardiomyocytes initiate cardiac contraction and blood pumping and maintain life. Abnormal electrical impulses bring patients with low heart rates to cardiac arrest. The current therapy is to implant electronic devices to generate backup electricity. However, complications inherent to electronic devices remain unbearable suffering. Therefore, cardiac biological pacing has been developed as a hardware-free alternative. The approaches to generating biological pacing have evolved recently using cell reprogramming technology to generate pacemaker cardiomyocytes in-vivo or in-vitro. Different from conventional methods by electrical re-engineering, reprogramming-based biological pacing recapitulates various phenotypes of de novo pacemaker cardiomyocytes and is more physiological, efficient, and easy for clinical implementation. This article reviews the present state of the art in reprogramming-based biological pacing. We begin with the rationale for this new approach and review its advances in creating a biological pacemaker to treat bradyarrhythmia.

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.

Leadless Pacemakers: Current Achievements and Future Perspectives

Despite the technological advances in pacemaker technology, the transvenous implanted leads are still considered the Achilles' heel of this rhythm-control therapy. The leadless permanent pacemaker system was developed as an option to bypass the weakness of the transvenous approach. Advances in battery technology and deep miniaturisation of electronics now offer the opportunity to implant the whole pacemaker system into the right ventricle. This review aims to provide a comprehensive report on the advent of leadless pacemakers, their clinical usefulness and the future perspectives of this disruptive and promising technology. Further research is required before some of these technologies are safely and routinely used in clinical practice.

Initial studies on the implanting sites of high and low ventricular septa using leadless cardiac pacemakers

OBJECTIVE

To study the safety and electrical characteristics of various implanting sites of the Micra pacemaker.

METHOD

A total of 15 patients from Beijing Anzhen Hospital, Capital Medical University, were included, who were implanted with Micra leadless pacemakers and allocated to either the high ventricular septum group (eight patients) or the low ventricular septum group (seven patients) based on their individual patient factors and clinical conditions. The baseline of the patients, the implanting area, the electrocardiogram change after implantation, the implantation data, the threshold, R wave, impedance, and the date of the 1-month follow-up were then analyzed. With all of the data, the characteristics of different implantation sites of the Micra pacemaker were determined.

RESULTS

Overall, the thresholds were low at implantation and remained stable over the 1-, 3-, 6-month, 1-, 2-, 3-, and 4-year follow-ups. On comparing the two groups, there was no difference in QRS duration at pacing (140.00 [40.00] ms vs. 179.00 [50.00] ms), threshold at implantation (0.38 [0.22] mV vs. 0.63 [1.00] mV), R wave at implantation ([10.85 ± 4.71] V vs. [7.26 ± 2.98] V), or impedance at implantation ([906.25 ± 162.39] Ω vs. [750.00 ± 173.40] Ω). While the difference in QRS duration between the two groups was not significant, the QRS duration of the high ventricular septum group exhibited a reduced tendency compared with that of the low ventricular group. The corrected QT interval during pacing exhibited a significant difference (440.00 [80.00] ms vs. 520.00 [100.00] ms; p < .05). For the 1-, 3-, 6-month, 1-, 2-, 3-, and 4-year follow-ups, there was no difference between the threshold of the high ventricular septum group and that of the low ventricular septum group (p > .05).

CONCLUSION

High ventricular septum pacing appears to be a safe site for implantation of the Micra pacemaker. It could entail a shorter QRS duration at pacing and could be more physiological than low ventricular septum pacing.

Prevention of device-related infections in patients with cancer: Current practice and future horizons

Over the past several years, multifaceted advances in the management of cancer have led to a significant improvement in survival rates. Throughout patients' oncological journeys, they will likely receive one or more implantable devices for the administration of fluids and medications as well as management of various comorbidities and complications related to cancer therapy. Infections associated with these devices are frequent and complex, often necessitating device removal, increasing health care costs, negatively affecting quality of life, and complicating oncological care, usually leading to delays in further life-saving cancer therapy. Herein, the authors comprehensively review multiple evidence-based recommendations along with best practices, expert opinions, and novel approaches for the prevention of diverse device-related infections. The authors present many general principles for the prevention of these infections followed by specific device-related recommendations in a systematic manner. The continuous involvement and meaningful cooperation between regulatory entities, industry, specialty medical societies, hospitals, and infection control-targeted interventions, along with primary care and consulting health care providers, are all vital for the sustained reduction in the incidence of these preventable infections.

Leadless Cardiac Pacing: New Horizons

Since the introduction of transvenous cardiac pacing leads, pacemaker system design has remained similar for several decades. Progressive miniaturisation of electronic circuitry and batteries has enabled a smaller, single pacing unit comprising the intracardiac electrodes, generator and computer. This review explores the development of leadless pacing, the clinical trials comparing leadless to transvenous pacing in addition to the future developments of multi-chamber leadless pacing.

A leadless pacemaker matched with a vasovagal syncope: how long can it last?

BACKGROUND

Guidelines recommend that cardiac pacing should be considered in patients suffering from frequent vasovagal syncopal (VVS) episodes. Studies have demonstrated the safety and efficacy of leadless pacemakers (LP) in cardioinhibitory vasovagal populations specifically, rendering them a reasonable alternative to transvenous pacing in these patients. However, due to the paucity of data on extraction and the number of concomitant LPs that can be safely implanted, there are concerns regarding LPs' battery longevity, especially in younger patients who may require decades of pacing therapy.

METHODS

This is a retrospective analysis of the first 100 LPs implanted at a tertiary cardiac centre in the UK. Demographical data and device parameters at implant and follow-ups were obtained from the hospital's medical records. The battery life of the LPs in the VVS patients was compared to that of patients with other pacing indications.

RESULTS

Ninety patients were included in the analysis. 14 patients (15.6%) had VVS, and 76 patients (84.4%) had other indications for pacing. Mean ages were 34 ± 13 years and 62 ± 20 years for the VVS and the other group, respectively. The estimated total battery life was 15.22 ± 0.35 and 13.65 ± 2.97 years in the VVS and the other indications group respectively (p = .04). There were no complications in the VVS group.

CONCLUSION

LPs provide a promising treatment for patients with vasovagal syncope with reassuring battery performance at the short/intermediate term. Further longer-term follow-up data are needed to identify the true battery potential in this patient cohort.

Leadless Pacemaker Implantation for a Super-elderly Woman with a Mediastinal Tumor

A 95-year-old woman with no cardiac history presented with symptomatic complete atrioventricular block. She underwent temporary cardiac pacing via the cervical vein, but a pacing lead could not be introduced via the usual route because of a mediastinal tumor. A leadless pacemaker (Micra™; Medtronic, Minneapolis, USA) was implanted at the right ventricular septum via the right femoral vein. The procedure time was 40 minutes, with no complications noted. Over the two-year follow-up period, the threshold and impedance remained stable. The implantation of a leadless pacemaker was useful for improving the symptoms of a super-elderly woman with a mediastinal tumor.

New Insights in Central Venous Disorders. The Role of Transvenous Lead Extractions

Over the last decades, the implementation of new technology in cardiac pacemakers and defibrillators as well as the increasing life expectancy have been associated with a higher incidence of transvenous lead complications over time. Variable degrees of venous stenosis at the level of the subclavian vein, the innominate trunk and the superior vena cava are reported in up to 50% of implanted patients. Importantly, the number of implanted leads seems to be the main risk factor for such complications. Extraction of abandoned or dysfunctional leads is a potential solution to overcome venous stenosis in case of device upgrades requiring additional leads, but also, in addition to venous angioplasty and stenting, to reduce symptoms related to the venous stenosis itself, i.e., the superior vena cava syndrome. This review explores the role of transvenous lead extraction procedures as therapeutical option in case of central venous disorders related to transvenous cardiac leads. We also describe the different extraction techniques available and other clinical indications for lead extractions such as lead infections. Finally, we discuss the alternative therapeutic options for cardiac stimulation or defibrillation in case of chronic venous occlusions that preclude the implant of conventional transvenous cardiac devices.

[New developments in leadless pacing systems]

Leadless pacing systems, especially the Micra™ TPS system, deliver an effective and safe alternative to the previous conventional transvenous systems in patients with impossible transvenous access and seem to be compatible with other implantable devices (S-ICD, deep brain stimulators) with no limitations in efficacy or safety. Also, new outlooks on leadless resynchronization therapy seem promising and could prevent future patients from lead- or operation-associated complications. Current limits to the implementation in everyday clinical practice are mostly the unavailability of the devices or cost issues through lack of health insurance reimbursement. However, more promising data through further studies and rising implantation rates are expected based on the positive current clinical data.

Peri-procedural management, implantation feasibility, and short-term outcomes in patients undergoing implantation of leadless pacemakers: European Snapshot Survey

The aim of this European Heart Rhythm Association (EHRA) prospective snapshot survey is to assess procedural settings, safety measures, and short-term outcomes associated with implantation of leadless pacemakers (LLPM), across a broad range of tertiary European electrophysiology centres. An internet-based electronic questionnaire (30 questions) concerning implantation settings, peri-procedural routines, complications, and in-hospital patient outcomes was circulated to centres routinely implanting both LLPMs and transvenous pacemakers (TV-PM). The centres were requested to prospectively include consecutive patients implanted with either LLPMs or TV-PMs during the 10-week enrolment period. Overall, 21 centres from four countries enrolled 825 consecutive patients between November 2018 and January 2019, including 69 (9%) implanted with LLPMs. Leadless pacemakers were implanted mainly under local anaesthesia (69%), by an electrophysiologist (60%), in the electrophysiology laboratory (71%); 95% of patients received prophylactic antibiotics prior to implantation. Most patients on chronic oral anticoagulation were operated on-drug (35%), or during short-term (to 48 h) drug withdrawal (54%). Implantation was successful in 98% of patients and the only in-hospital procedure-related complication was groyne haematoma in one patient. This EHRA snapshot survey provides important insights into LLPM implantation routines and patient outcomes. These findings suggest that despite the unfavourable clinical profile of pacemaker recipients, LLPM implantation is associated with relatively low risk of complications and good short-term outcomes.

What Promotes Surgeon Practice Change? A Scoping Review of Innovation Adoption in Surgical Practice

OBJECTIVE

The goal of this scoping review was to summarize the literature on facilitators and barriers to surgical practice change. This information can inform research to implement best practices and evaluate new surgical innovations.

BACKGROUND

In an era of accelerated innovations, surgeons face the difficult decision to either acknowledge and implement or forgo new advances. Although changing surgical practice to align with evidence is an imperative of health systems, evidence-based guidelines have not translated into consistent change. The literature on practice change is limited and has largely focused on synthesizing information on methods and trials to evaluate innovative surgical interventions. No reviews to date have grounded their analysis within an implementation science framework.

METHODS

A systematic review of the literature on surgical practice change was performed. Abstracts and full-text articles were reviewed for relevance using inclusion and exclusion criteria and data were extracted from each article. Cited facilitators and barriers were then mapped across domains within the implementation science Theoretical Domains Framework and expanded to the Capability, Opportunity, Motivation, and Behavior model.

RESULTS

Components of the Capability, Opportunity, Motivation, and Behavior model were represented across the Theoretical Domains Framework domains and acted as both facilitators and barriers to practice change depending on the circumstances. Domains that most affected surgical practice change, in order, were: opportunity (environmental context and resources and social influences), capability (knowledge and skills), and motivation (beliefs about consequences and reinforcement).

CONCLUSIONS

Practice change is predicated on a conducive environment with adequate resources, but once that is established, the surgeon's individual characteristics, including skills, motivation, and reinforcement determine the likelihood of successful change. Deficiencies in the literature underscore the need for further study of resource interventions and the role of surgical team dynamics in the adoption of innovation. A better understanding of these areas is needed to optimize our ability to disseminate and implement best practices in surgery.

Cardiac Stimulation in the Third Millennium: Where Do We Head from Here?

Over the years, pacemakers have evolved from a life-saving tool to prevent asystole to a device to treat heart rhythm disorders and heart failure, aiming at improving both cardiac function and clinical outcomes. Cardiac stimulation nowadays aims to correct the electrophysiologic roots of mechanical inefficiency in different structural heart diseases. This has led to awareness of the concealed risks of customary cardiac pacing that can inadvertently cause atrioventricular and inter-/intra-ventricular dyssynchrony, and has promoted the development of new pacing modalities and the use of stimulation sites different from the right atrial appendage and the right ventricular apex. The perspective of truly physiologic pacing is the leading concept of the continued research in the past 30 years, which has made cardiac stimulation procedure more sophisticated and challenging. In this article, we analyze the emerging evidence in favor of the available strategies to achieve an individualized physiologic setting in bradycardia pacing.

Pacing devices to treat bradycardia: current status and future perspectives

Introduction: Cardiac stimulation evolved from life-saving devices to prevent asystole to the treatment of heart rhythm disorders and heart failure, capable of remote patient and disease-progression monitoring. Cardiac stimulation nowadays aims to correct the electrophysiologic roots of mechanical inefficiency in different structural heart diseases.Areas covered: Clinical experience, as per available literature, has led to awareness of the concealed risks of customary cardiac pacing, that can inadvertently cause atrio-ventricular and inter/intra-ventricular dyssynchrony. New pacing modalities have emerged, leading to a new concept of what truly represents 'physiologic pacing' beyond maintenance of atrio-ventricular coupling. In this article we will analyze the emerging evidence in favor of the available strategies to achieve an individualized physiologic setting in bradycardia pacing, and the hints of future developments.Expert opinion: 'physiologic stimulation' technologies should evolve to enable an effective and widespread adoption. In one way new guiding catheters and the adoption of electrophysiologic guidance and non-fluoroscopic lead implantation are needed to make His-Purkinje pacing successful and effective at long term in a shorter procedure time; in the other way leadless stimulation needs to upgrade to a superior physiologic setting to mimic customary DDD pacing and possibly His-Purkinje pacing.

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.

Leadless pacemakers - The path to safer pacing?

Endocardial transvenous permanent pacemakers (TVPs) are a mainstay within cardiology and used to treat a range of bradyarrhythmias. However, their use is associated with potential complications both at the time of implantation and longer term. The concept of a leadless pacemaker, where a self-contained device is placed within the right ventricle, has obvious attractions. Two leadless systems have been developed, though only one is currently available. Results from clinical trials have been promising but a number of hurdles need to be circumvented before leadless devices can usurp TVPs. At present, use is restricted to specialist centres, for a limited indication and for patients in whom conventional implantation is contraindicated. This article provides a contemporary critique of design types, evidence base and existing limitations of this nascent technology.

[Symptomatic bradycardia with exitblock in a leadless pacemaker]

The pacemaker is the treatment of choice for symptomatic bradycardic arrhythmias. However, pacemaker patients may develop further bradycardial arrhythmias, often due to a pacemaker dysfunction. The possible causes range from lead problems to complete system failure. The Nanostim^TM system is a leadless pacemaker. The advantages include the lead-free design and the catheter-based implantation. In 2016, all Nanostim^TM implantations were stopped due to a battery dysfunction.

Nanostim-leadless pacemaker

Nanostim™ (St. Jude Medical Inc., Saint Paul, MN, USA; now Abbott Medical Inc. Abbott Park, IL, USA) was the first self-contained intracardiac pacemaker to be implanted in a human patient. A total of 1423 Nanostim devices were implanted worldwide between 2013 and 2016 and three clinical trials were initiated. Although the device was recalled in 2016 owing to rare but serious battery failures, the concept of leadless pacing has gained widespread acceptance and is expanding beyond the initial single-chamber devices to dual-chamber systems, biventricular pacing, and combinations with defibrillators. This review describes the design, results from initial clinical trials, and long-term experiences with Nanostim. It discusses the lessons learned from the pioneering device's successes and shortcomings, many of which are valid for leadless pacemakers in general. This article also considers the Nanostim experience in comparison with the early years of clinical use for other pioneering device therapies. Important questions include how to minimize the risk for short-term complications by appropriate operator training and evaluation of suitable patients, what the long-term performance tells us about safety, as well as the necessity and feasibility of device explantation.