Lessons from the first patient with an implanted pacemaker: 1958-2001

The world's longest lasting VVI pacemaker device for over 40 years

INTRODUCTION

Implantable permanent pacemaker function is supported by their energy sources for a mean period of 8.8-12.4 years. We previously published this case of a patient with a normally functioning VVI pacemaker, 31 years after implantation.

METHODS AND RESULTS

In this report, we state that the device is still functioning normally 40 years after implantation. The most recent device interrogation revealed pacing threshold of 0.9 V/0.5 ms. Holter monitoring for 24 hours recorded a total of 98.707 beats with 97.78% paced beats, without any indication of pacemaker malfunction and with stable heart rate at 70-71 bpm.

CONCLUSION

Most patients with implantable devices have the appropriate follow-up and settings of low energy consumption. Manufacturing companies should focus on prolonging device longevity, to produce future devices with higher energy capacity.

Five historical innovations that have shaped modern cardiothoracic surgery

Throughout history, many innovations have contributed to the development of modern cardiothoracic surgery, improving patient outcomes and expanding the range of treatment options available to patients. This article explores five key historical innovations that have shaped modern cardiothoracic surgery: cardiopulmonary bypass, surgical pacemakers, video assisted thoracic surgery, robotic surgery and mechanical circulatory support. We will review the development, impact and significance of each innovation, highlighting their contributions to the field of cardiothoracic surgery and their ongoing relevance in contemporary and perioperative practice.

[Sixty-five years of pacemaker therapy]

Sixty-five years ago, the first pacemakers were implanted. Swedish developments paved the way for implantation of the first epicardial pacemaker with a rechargeable battery unit; however, there was a battery defect within 3 h. Further developments in the USA allowed for the first transvenous, endocardial lead to be implanted with an external pacemaker battery. Following these pioneering implantations, further improvements of the battery and electrical elements and also of lead technology (flexibility and fixation mechanism) allowed the implantation of pacemaker systems similar to those we still implant today.

Case report: Challenges and implications of conduction system pacing in pediatrics: Case series

Cardiac electrical stimulation in children usually is needed in the setting of complete congenital atrioventricular block, atrioventricular block after heart surgery, and bradycardia associated with some specific channelopathies. In cases of atrioventricular block, the high percentage of ventricular stimulation raises concern on the deleterious effects of chronic stimulation of the right ventricle. In recent years, physiologic stimulation has developed as a valid approach for adult patients and a great interest has risen in offering conduction system pacing also to the pediatric population. We present three pediatric cases of stimulation of the conduction system (His bundle or left bundle branch), in order to show the intrinsic particularities and challenges implied in these new techniques.

Pulmonary hemorrhage after cardiac resynchronization therapy device implantation - A systematic review

Cardiac implantable electronic devices are being increasingly used for a variety of cardiovascular diseases. We describe a rare case of massive hemoptysis after device implantation. The patient was managed conservatively with reversal of anticoagulation and inhaled tranexamic acid and had a successful recovery. A systematic review accompanies the case presentation. The modality and difficulty of access appear to play a significant role in precipitating bleeding, believed to be the result of direct injury to the pulmonary parenchyma and vasculature. The condition is often self-limiting; however, anticoagulation reversal, intubation, endobronchial intervention, and transarterial embolization may be indicated in more severe pulmonary hemorrhage.

Epidemiology of subclinical atrial fibrillation in patients with cardiac implantable electronic devices: A systematic review and meta-regression

BACKGROUND

In recent years, attention to subclinical atrial fibrillation (SCAF), defined as the presence of atrial high-rate episodes (AHREs), in patients with cardiac implantable electronic devices (CIEDs), has gained much interest as a determinant of clinical AF and stroke risk. We aim to perform a systematic review and meta-regression of the available scientific evidence regarding the epidemiology of SCAF in patients receiving CIEDs.

METHODS

PubMed and EMBASE were searched for all studies documenting the prevalence of AHREs in patients (n=100 or more, <50% with history of AF) with CIEDs from inception to 20th August 2021, screened by two independent blind reviewers. This study was registered in PROSPERO: CRD42019106994.

RESULTS

Among the 2614 results initially retrieved, 54 studies were included, with a total of 72,784 patients. Meta-analysis of included studies showed a pooled prevalence of SCAF of 28.1% (95%CI: 24.3-32.1%), with high heterogeneity between studies (I²=98%). A multivariable meta-regression was able to explain significant proportion of heterogeneity (R²=61.9%, p<0.001), with age and follow-up time non-linearly, directly and independently associated with occurrence of SCAF. Older age, higher CHA₂DS₂-VASc score, history of AF, hypertension, CHF, and stroke/TIA were all associated with SCAF occurrence.

CONCLUSIONS

In this systematic review and meta-regression analysis, SCAF was frequent among CIED recipients and was non-linearly associated with age and follow-up time. Older age, higher thromboembolic risk, and several cardiovascular comorbidities were associated with presence of SCAF.

Tricuspid Regurgitation Related to Cardiac Implantable Electronic Devices: An Integrative Review

The use of cardiac implantable electronic devices, including permanent pacemakers, implantable cardiac defibrillators and cardiac resynchronization therapy, has dramatically increased in recent years. The interaction between the device lead and tricuspid valve leaflets is a potential cause of tricuspid regurgitation which in turn has an impact on morbidity and mortality. Echocardiography is necessary for grading of tricuspid regurgitation severity. The use of three-dimensional imaging helps determine whether the device lead is interfering with normal leaflet coaptation. Early identification of lead-related tricuspid regurgitation is critical to select the optimal treatment, which may include lead extraction or even tricuspid valve repair/replacement in severe cases. This review aims to provide a thorough assessment of the evidence about lead-associated tricuspid regurgitation, the benefits of using 3D echocardiography with some technical considerations, and finally, propose a treatment algorithm.

Emerging Technologies in Electrophysiology: From Single Chamber to Biventricular Leadless Pacemakers

BACKGROUND

Transvenous pacemakers have been shown to improve quality of life and mortality in patients with bradycardia and cardiac conduction blocks. However, they possess inevitable drawbacks as they have a relatively high incidence of lead and device pocket-related complications. Therefore, leadless pacemakers have emerged as a solution to reduce the complications seen with conventional pacemakers. However, there have been no clinical trials to date comparing transvenous to leadless pacemakers.

SUMMARY

Currently, the Micra TPS or AV device has been approved for commercial use worldwide but is limited to single-chamber pacing with single or dual-chamber sensing. Although the leadless pacemaker, Nanostim, was initially promising, it has been recalled due to concerns of battery failures and is no longer approved in Europe. In addition, the lack of defibrillation capabilities with leadless pacemakers has been a limiting factor; therefore, a leadless pacemaker with the already approved subcutaneous cardioverter-defibrillator system is currently being studied in humans. Moreover, the WiSE-CRT device has been approved in Europe, with the capabilities for leadless cardiac resynchronization therapy (CRT), to provide CRT for patients with unsuitable coronary sinus anatomy. Furthermore, retrieval of leadless pacemakers has been an area of concern; however, clinic data has signaled towards safe extraction of these devices with minimal complications. Key messages: This review will encompass the current literature regarding clinical safety and outcomes of these novel leadless pacemakers and discuss the evolving technologies in the field of cardiac pacing.

Remote Monitoring of CIEDs-For Both Safety, Economy and Convenience?

Cardiac implantable electronic devices such as pacemakers and defibrillators are increasingly monitored by systems transmitting information directly from the patient to the hospital. This may increase safety and patient satisfaction and also under certain circumstances represent an economic advantage. The review summarizes some of the recent research in the field of remote monitoring of 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.

Outcomes and Echocardiographic Follow-up After Surgical Management of Tricuspid Regurgitation in Patients With Transvenous Right Ventricular Leads

OBJECTIVE

To evaluate outcomes of elective surgical management of tricuspid regurgitation (TR) in patients with transvenous right ventricular leads, and compare results between non-lead-induced and lead-induced TR patients.

PATIENTS AND METHODS

We studied patients with right ventricular leads who underwent tricuspid valve surgery from January 1, 1993, through December 31, 2015, and categorized them as non-lead-induced and lead-induced TR. Propensity score (PS) for the tendency to have lead-induced TR was estimated from logistic regression and was used to adjust for group differences.

RESULTS

From the initial cohort of 470 patients, 444 were included in PS-adjustment analyses (174 non-lead-induced TRs [123 repairs, 51 replacements], 270 lead-induced TRs [129 repairs, 141 replacements]). In PS-adjusted multivariable analysis, lead-induced TR was not associated with mortality (P=.73), but tricuspid valve replacement was (hazard ratio, 1.59; 95% CI, 1.13 to 2.25; P=.008). Five-year freedom from tricuspid valve re-intervention was 100% for non-lead-induced TR and 92.3% for lead-induced TR; rates adjusted for PS differed between groups (P=.005). There was significant improvement in TR postoperatively in each group (P<.001). In patients having tricuspid valve repair, TR grades tended to worsen over time, but the difference in trends was not significantly different between groups.

CONCLUSION

Lead-induced TR did not affect long-term survival after elective tricuspid valve surgery. In patients with lead-induced TR, tricuspid valve re-intervention was more common. Improvement in TR was achieved in both groups after surgery; however, severity of TR tended to increase over follow-up after tricuspid valve repair.

Self-powered technology based on nanogenerators for biomedical applications

Biomedical electronic devices have enormous benefits for healthcare and quality of life. Still, the long-term working of those devices remains a great challenge due to the short life and large volume of conventional batteries. Since the nanogenerators (NGs) invention, they have been widely used to convert various ambient mechanical energy sources into electrical energy. The self-powered technology based on NGs is dedicated to harvesting ambient energy to supply electronic devices, which is an effective pathway to conquer the energy insufficiency of biomedical electronic devices. With the aid of this technology, it is expected to develop self-powered biomedical electronic devices with advanced features and distinctive functions. The goal of this review is to summarize the existing self-powered technologies based on NGs and then review the applications based on self-powered technologies in the biomedical field during their rapid development in recent years, including two main directions. The first is the NGs as independent sensors to converts biomechanical energy and heat energy into electrical signals to reflect health information. The second direction is to use the electrical energy produced by NGs to stimulate biological tissues or powering biomedical devices for achieving the purpose of medical application. Eventually, we have analyzed and discussed the remaining challenges and perspectives of the field. We believe that the self-powered technology based on NGs would advance the development of modern biomedical electronic devices.

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.

Case Report: Assessing the Position of Pacemaker Leads via Transthoracic Echocardiography: Additional Value of the Subcostal En Face View

There is an association between presence of cardiac implantable electronic devices (CIED) and development of tricuspid regurgitation (TR). Mechanisms proposed to explain CIED-induced TR can be classified as implantation-related, lead-related, and pacing-related. Lead-related TR results from the direct interaction of the lead with the tricuspid valve (TV). The localization of the lead at the TV level directly influences the probability of subsequent development of significant TR. A transthoracic subcostal en face view of the TV can be acquired in most patients through a 90° rotation from the subcostal 4-chamber view with clear anatomic delineation of the TV and the commissures including lead position. This case-series presents three examples where the transthoracic en face view could add incremental information on the position of the pacemaker leads and on the mechanism of TR.

Conclusion: When performing transthoracic echocardiography in patients with trans-tricuspid CIED lead(s), an en face view of the TV with exact reporting of the position of the lead(s) should be included.

Innovations in Cardiac Implantable Electronic Devices

Cardiac implantable electronic devices (CIEDs) are essential for the management of a variety of cardiac conditions, including tachyarrhythmias, bradyarrhythmias, and medically refractory heart failure (HF). Recent advancements in CIED technology have led to innovative solutions that overcome shortcomings associated with traditional devices or address unmet needs. Leadless pacemakers, subcutaneous implantable cardioverter defibrillators (ICDs), and extravascular ICDs eliminate lead-related complications common with conventional pacemakers or ICDs. Conduction system pacing (His bundle pacing and left bundle branch pacing) is a more physiologic method of pacing and avoids the deleterious consequences associated with long-term right ventricular pacing. For HF-related devices, cardiac contractility modulation is an emerging therapy that bridges a gap for many patients ineligible for cardiac resynchronization therapy and has been shown to improve HF symptoms and decrease hospitalizations and mortality in select patients. Implantable pulmonary artery pressure monitors help guide HF management and reduce hospitalizations. Lastly, new phrenic nerve stimulating devices are being utilized to treat central sleep apnea, a common comorbidity associated with HF. While further long-term studies are still underway for many of these new technologies, it is anticipated that these devices will become indispensable therapeutics in the expanding cardiovascular armamentarium.

Reliability of Neural Implants-Effective Method for Cleaning and Surface Preparation of Ceramics

Neural implants provide effective treatment and diagnosis options for diseases where pharmaceutical therapies are missing or ineffective. These active implantable medical devices (AIMDs) are designed to remain implanted and functional over decades. A key factor for achieving reliability and longevity are cleaning procedures used during manufacturing to prevent failures associated with contaminations. The Implantable Devices Group (IDG) at University College London (UCL) pioneered an approach which involved a cocktail of reagents described as “Leslie’s soup”. This process proved to be successful but no extensive evaluation of this method and the cocktail’s ingredients have been reported so far. Our study addressed this gap by a comprehensive analysis of the efficacy of this cleaning method. Surface analysis techniques complemented adhesion strengths methods to identify residues of contaminants like welding flux, solder residues or grease during typical assembly processes. Quantitative data prove the suitability of “Leslie’s soup” for cleaning of ceramic components during active implant assembly when residual ionic contaminations were removed by further treatment with isopropanol and deionised water. Solder and flux contaminations were removed without further mechanical cleaning. The adhesive strength of screen-printed metalisation layers increased from 12.50 ± 3.83 MPa without initial cleaning to 21.71 ± 1.85 MPa. We conclude that cleaning procedures during manufacturing of AIMDs, especially the understanding of applicability and limitations, is of central importance for their reliable and longevity.

Emerging Technologies in Cardiac Pacing From Leadless Pacers to Stem Cells

Modern pacemakers can sense and pace multiple chambers of the heart. These pacemakers have different modes and features to optimize atrioventricular synchrony and promote intrinsic conduction. Despite recent advancements, current pacemakers have several drawbacks that limit their feasibility. In this review article, we discuss several of these limitations and detail several emerging technologies in cardiac pacing aimed to solve some of these limitations. We present several technological advancements in cardiac pacing, including the use of leadless pacemakers, physiologic pacing, battery improvements, and bioartificial pacemakers. More research still needs to be done in testing the safety and efficacy of these new developments.

The impact of permanent pacemaker implantation on thallium myocardial perfusion examination detecting ischemic heart disease

OBJECTIVES

Patients with permanent pacemaker (PPM) implantation may have altered coronary perfusion patterns that may influence the accuracy of myocardial perfusion examination modalities, which was observed in previous studies but with limited statistic power. Our aim was to examine the performance of thallium-201 (TL-201) myocardial perfusion examination in patients with implanted PPM.

METHODS

Data of consecutive patients from our institution who had coronary angiography examination followed by TL-201 myocardial perfusion examination in pairs within 1 year were collected between January 2010 and December 2016 and were divided into PPM and control groups. Propensity score matching (PSM) was performed to compare the positive predictive value (PPV) of perfusion examinations.

RESULTS

A total of 934 pairs of studies were evaluated, with 81 in the PPM group and 853 controls. The PPV decreased significantly in the PPM group (28.2 vs. 62.9%, P < 0.001). The finding of large (>20%) ischemic areas correlated significantly with all-cause mortality in the control group (OR, 2.34; P = 0.001), but not in the PPM group (OR,1.05; P = 0.943). After PSM, the PPV was still significantly lower in the PPM group than in the non-PPM group (28.6 vs. 66.2%, P < 0.001).

CONCLUSION

Study results do not support the appropriateness of using TL-201 perfusion examinations for risk stratification in patients with implanted PPM.Video Abstract: http://links.lww.com/NMC/A181.

Self-powered cardiovascular electronic devices and systems

Cardiovascular electronic devices have enormous benefits for health and quality of life but the long-term operation of these implantable and wearable devices remains a huge challenge owing to the limited life of batteries, which increases the risk of device failure and causes uncertainty among patients. A possible approach to overcoming the challenge of limited battery life is to harvest energy from the body and its ambient environment, including biomechanical, solar, thermal and biochemical energy, so that the devices can be self-powered. This strategy could allow the development of advanced features for cardiovascular electronic devices, such as extended life, miniaturization to improve comfort and conformability, and functions that integrate with real-time data transmission, mobile data processing and smart power utilization. In this Review, we present an update on self-powered cardiovascular implantable electronic devices and wearable active sensors. We summarize the existing self-powered technologies and their fundamental features. We then review the current applications of self-powered electronic devices in the cardiovascular field, which have two main goals. The first is to harvest energy from the body as a sustainable power source for cardiovascular electronic devices, such as cardiac pacemakers. The second is to use self-powered devices with low power consumption and high performance as active sensors to monitor physiological signals (for example, for active endocardial monitoring). Finally, we present the current challenges and future perspectives for the field.

Towards the clinical translation of optogenetic skeletal muscle stimulation

Paralysis is a frequent phenomenon in many diseases, and to date, only functional electrical stimulation (FES) mediated via the innervating nerve can be employed to restore skeletal muscle function in patients. Despite recent progress, FES has several technical limitations and significant side effects. Optogenetic stimulation has been proposed as an alternative, as it may circumvent some of the disadvantages of FES enabling cell type–specific, spatially and temporally precise stimulation of cells expressing light-gated ion channels, commonly Channelrhodopsin2. Two distinct approaches for the restoration of skeletal muscle function with optogenetics have been demonstrated: indirect optogenetic stimulation through the innervating nerve similar to FES and direct optogenetic stimulation of the skeletal muscle. Although both approaches show great promise, both have their limitations and there are several general hurdles that need to be overcome for their translation into clinics. These include successful gene transfer, sustained optogenetic protein expression, and the creation of optically active implantable devices. Herein, a comprehensive summary of the underlying mechanisms of electrical and optogenetic approaches is provided. With this knowledge in mind, we substantiate a detailed discussion of the advantages and limitations of each method. Furthermore, the obstacles in the way of clinical translation of optogenetic stimulation are discussed, and suggestions on how they could be overcome are provided. Finally, four specific examples of pathologies demanding novel therapeutic measures are discussed with a focus on the likelihood of direct versus indirect optogenetic stimulation.

State of the art: leadless ventricular pacing : A national expert consensus of the Austrian Society of Cardiology

Background

Cardiac pacing has been shown to improve quality of life and prognosis of patients with bradycardia for almost 60 years. The latest innovation in pacemaker therapy was miniaturization of generators to allow leadless pacing directly in the right ventricle. There is a long history and extensive experience of leadless ventricular pacing in Austria. However, no recommendations of national or international societies for indications and implantation of leadless opposed to transvenous pacing systems have been published so far.

Results

A national expert panel of skilled implanters gives an overview on the two utilized leadless cardiac pacing systems and highlights clinical advantages as well as current knowledge of performance and complication rates of leadless pacing. Furthermore, a national consensus for Austria is presented, based on recent studies and current know-how, specifically including indications for leadless pacing, management of infection, suggestions for qualification, and training of the operators and technical standards.

Conclusions

Leadless pacing systems can be implanted successfully with a low complication rate, if suggestions for indications and technical requirements are followed.

Condensed abstract

An overview of the two utilized leadless cardiac pacing systems is given, specifically highlighting clinical advantages as well as current knowledge of performance and complication rates. Furthermore, a national consensus for Austria is presented, specifically including indications for leadless pacing, management of infection, and suggestions for qualification and technical standards.

Prognostic significance of non-sustained ventricular tachycardia on stored electrograms in pacemaker recipients

Background

Little is known about the prognostic significance of non-sustained ventricular tachycardia (NS-VT) in outpatients scheduled for routine pacemaker controls. We therefore sought to investigate the prognostic significance of non-sustained ventricular tachycardia on stored electrograms in pacemaker recipients.

Methods

We enrolled patients implanted with dual chamber pacemaker for atrioventricular block or sinus node dysfunction from 2010 to 2016, with LVEF> 45%, older than 18 years, with at least 3 device interrogations at follow-up. Data were collected about medical history, pharmacological therapy at implantation, pacemaker programming, NS-VT occurrence, long-term survival.

Results

A total of 308 patients were included in the final analysis, with median follow-up time of 56 months. No ventricular arrhythmic episodes were documented in 221 patients (Group 1), whereas 87 had at least 1 episode of NS-VT during follow-up (Group 2). As a whole, 282 episodes of NS-VT were documented. There was a higher prevalence of previous myocardial infarction and slightly lower left ventricular ejection fraction (LVEF) in Group 2. The primary endpoint (all-cause mortality) occurred in 50 patients (22%) of Group 1 and 12 (14%) patients of Group 2 (p = 0.07). Clinical predictors of all-cause mortality at univariate analysis included age, LVEF and coronary artery disease (CAD). Only age and CAD, however, remained as predictors of mortality at multivariable analysis. A sizeable, but not statistically significant, portion of patients who died had a de novo occurrence of NS-VT at the last pacemaker check.

Conclusion

Our data do not support a prognostic role for the detection of NS-VT during pacemaker controls.

Electrical connectors for neural implants: design, state of the art and future challenges of an underestimated component

Technological advances in electrically active implantable devices have increased the complexity of hardware design. In particular, the increasing number of stimulation and recording channels requires innovative approaches for connectors that interface electrodes with the implant circuitry.

OBJECTIVE

This work aims to provide a common theoretical ground for implantable connector development with a focus on neural applications.

APPROACH

Aspects and experiences from several disciplines are compiled from an engineering perspective to discuss the state of the art of connector solutions. Whenever available, we also present general design guidelines.

MAIN RESULTS

Degradation mechanisms, material stability and design rules in terms of biocompatibility and biostability are introduced. Considering contact physics, we address the design and characterization of the contact zone and review contaminants, wear and contact degradation. For high-channel counts and body-like environments, insulation can be even more crucial than the electrical connection itself. Therefore, we also introduce the requirements for electrical insulation to prevent signal loss and distortion and discuss its impact on the practical implementation.

SIGNIFICANCE

A final review is dedicated to the state of the art connector concepts, their mechanical setup, electrical performance and the interface to other implant components. We conclude with an outlook for possible approaches for the future generations of implants.

Biocompatible Symmetric Na-Ion Microbatteries with Sphere-in-Network Heteronanomat Electrodes Realizing High Reliability and High Energy Density for Implantable Bioelectronics

The prolonged life expectancy accelerates the development of implantable bioelectronic devices. However, conventional batteries with limited lifetime, rigid architecture, and inferior energy density greatly restrict their applications in patient's body. Herein, a novel flexible symmetric Na-ion microbattery based on the heteronanomat electrode and the biocompatible electrolyte has been developed. The film electrodes with sphere-in-network architecture are synthesized by simultaneously electrospinning and electrospraying followed by carbonization. The combined technologies allow a uniform incorporation of active materials/C spheres into the carbon nanofiber matrix, which results in the heteronanomat electrodes with robust structure, fast electron/ion transport, and compact mass loading. The flexible microbatteries are fabricated based on the interdigitated microelectrodes and the biocompatible electrolytes, which provides a new implantable power source for bioelectronics. As a proof-of-concept study, the symmetric sodium-ion microbatteries are constructed from the heteronanomat bifunctional electrodes (based on Na₂VTi(PO₄)₃) and the biocompatible electrolyte. The high reversibility, fast kinetics, and high energy density of the symmetric system in the biocompatible electrolytes reveal their superior performance in bioenvironments. Moreover, the high capacity retention (over 98%) and the high stability of microbattery implanted in a living SD rat for a month further demonstrate its high reliability for long-term in vivo diagnosis. Therefore, this work not only presents a new sphere-in-net heteronanomat structure for fabricating high-performance electrode but also gives significant contributions to develop high-energy-density and high safety biocompatible power sources of implantable bioelectronics.

Prognosis of patients with implanted pacemakers in 4‑year follow-up : Impact of right ventricular pacing site

BACKGROUND

Pacing remains the method of choice for treatment of cardiac electrical conduction disorders. This study examined the interrelationship between the site of the right ventricular lead tip and patient prognosis in association with other cardiovascular risk factors over a 4‑year follow-up period.

PATIENTS AND METHODS

The study comprised 450 consecutive patients (223 women; aged 69.16 ± 9.63 years) who had their first SSI or DDD pacemaker implanted for typical indications.

RESULTS

During follow-up, 91 (20.2%) patients died. The positive prognostic factors were: female sex (hazard ratio [HR] = 0.426), DDD pacemaker (HR = 0.526), oral anticoagulant use (HR = 0.330; all groups), sodium concentration (HR = 0.926), oral anticoagulant (HR = 0.115) and statin (HR = 0.260) use (female group), and non-apical location of the right ventricular lead tip (HR = 0.549; male group). Risk factors for death were: age (HR = 1.063), diabetes requiring insulin (HR = 2.832), creatinine concentration (HR = 1.005; all groups), age (HR = 1.11; female group), and elevated creatinine level (HR = 1.012; male group). In all patients, the non-apical location of the right ventricular lead tip was associated with an 18.92% reduced mortality rate during the 4‑year follow-up, which was statistically significant for the male group.

CONCLUSION

The non-apical location of the right ventricular lead tip was a positive prognostic factor and was statistically significant in the male subgroup.

Next-generation pacemakers: from small devices to biological pacemakers

Electrogenesis in the heart begins in the sinoatrial node and proceeds down the conduction system to originate the heartbeat. Conduction system disorders lead to slow heart rates that are insufficient to support the circulation, necessitating implantation of electronic pacemakers. The typical electronic pacemaker consists of a subcutaneous generator and battery module attached to one or more endocardial leads. New leadless pacemakers can be implanted directly into the right ventricular apex, providing single-chamber pacing without a subcutaneous generator. Modern pacemakers are generally reliable, and their programmability provides options for different pacing modes tailored to specific clinical needs. Advances in device technology will probably include alternative energy sources and dual-chamber leadless pacing in the not-too-distant future. Although effective, current electronic devices have limitations related to lead or generator malfunction, lack of autonomic responsiveness, undesirable interactions with strong magnetic fields, and device-related infections. Biological pacemakers, generated by somatic gene transfer, cell fusion, or cell transplantation, provide an alternative to electronic devices. Somatic reprogramming strategies, which involve transfer of genes encoding transcription factors to transform working myocardium into a surrogate sinoatrial node, are furthest along in the translational pipeline. Even as electronic pacemakers become smaller and less invasive, biological pacemakers might expand the therapeutic armamentarium for conduction system disorders.

Keeping up appearances: the radiographic evolution of cardiovascular implantable electronic devices

In recent years, there has been a significant evolution in the field of cardiovascular implantable electronic devices (CIEDs). Pacemakers can now be leadless, implantable cardioverter defibrillators can be entirely subcutaneous and implantable loop recorders have become miniaturized. Driven by technological advances and an ageing population implant numbers have also steadily increased. These highly prevalent systems are all radio-opaque and are frequently observed on chest radiographs, yet the devices are neither well recognized nor understood. We present a pictorial review of CIEDs; describing the chest radiograph appearances of both newer generation systems and their traditional predecessors. Furthermore, we discuss the clinical role of chest radiography in both CIED implantation and follow up, with the aim of improving understanding in this important and expanding field. Finally, we present a collection of interesting and challenging radiographs, where multiple CIED systems have been implanted.

Lead or be led: an update on leadless cardiac devices for general physicians

Implantable cardiac devices have an increasingly important role. Pacemakers remain the only effective treatment for symptomatic bradycardia; cardiac resynchronisation therapy is a proven treatment for heart failure; and implantable cardioverter defibrillators (ICD) are superior to medical therapy in prevention of sudden cardiac death. Our ageing population has led to a rising number of device implants. Physicians in all specialties increasingly encounter patients with cardiac devices and require an understanding of their capabilities and functions. The rising prevalence of implantable devices has been matched by a parallel expanse in device technology. Leadless devices have become a reality and represent the future of device therapy. The absence of a transvenous lead offers a significant clinical advantage because of many well established issues related to lead complications. The leadless pacemaker and subcutaneous ICD are significant new products that are currently not well recognised or understood by general physicians.

Clinical Significance of Nonsustained Ventricular Tachycardia on Stored Electrograms in Permanent Pacemaker Patients

BACKGROUND

Permanent pacemaker electrograms record a variety of arrhythmias, including nonsustained ventricular tachycardia (NSVT). Little has been reported regarding incidence and clinical significance of NSVT in pacemaker patients after long-term monitoring.

METHODS

Records from all patients implanted with Medtronic pacemakers (Medtronic, Minneapolis, MN, USA) at a single institution from January 1, 2009 to February 27, 2012 were reviewed. Demographic characteristics, imaging studies, pacemaker interrogations, and the Social Security Death Index were examined in patients older than 18 years of age who had ≥ 2 follow-up device interrogations.

RESULTS

A total of 262 patients with an ejection fraction (EF) >40% were included in the final analysis with a mean follow-up of 29.2 months. Of these patients, 83.2% (n = 218) had hypertension (HTN) and 45.4% (n = 119) had NSVT. Among patients with an EF ≥ 55%, hypertensive patients had a NSVT burden 2.46 times greater than normotensive patients (incidence rate ratio: 2.46, 95% confidence interval: 1.10-5.50; P < 0.028). NSVT was not associated with increased mortality (P < 0.1229).

CONCLUSION

In this cohort of patients, there was a high prevalence of HTN and while hypertensive subjects had a significantly higher NSVT burden, NSVT was not associated with an increased mortality.

Biomedical engineering education--status and perspectives

Biomedical Engineering programs are present at a large number of universities all over the world with an increasing trend. New generations of biomedical engineers have to face the challenges of health care systems round the world which need a large number of professionals not only to support the present technology in the health care system but to develop new devices and services. Health care stakeholders would like to have innovative solutions directed towards solving problems of the world growing incidence of chronic disease and ageing population. These new solutions have to meet the requirements for continuous monitoring, support or care outside clinical settlements. Presence of these needs can be tracked through data from the Labor Organization in the U.S. showing that biomedical engineering jobs have the largest growth at the engineering labor market with expected 72% growth rate in the period from 2008-2018. In European Union the number of patents (i.e. innovation) is the highest in the category of biomedical technology. Biomedical engineering curricula have to adopt to the new needs and for expectations of the future. In this paper we want to give an overview of engineering professions in related to engineering in medicine and biology and the current status of BME education in some regions, as a base for further discussions.

Radiotherapy in patients with pacemakers and implantable cardioverter defibrillators: a literature review

An increasing number of patients with implantable cardiac rhythm devices undergo radiotherapy (RT) for cancer and are thereby exposed to the risk of device failure. Current safety recommendations seem to have limitations by not accounting for the risk of pacemakers and implantable cardioverter defibrillators malfunctioning at low radiation doses. Besides scant knowledge about optimal safety measures, only little is known about the exact prevalence of patients with devices undergoing RT. In this review, we provide a short overview of the principles of RT and present the current evidence on the predictors and mechanisms of device malfunctions during RT. We also summarize practical recommendations from recent publications and from the industry. Strongly associated with beam energy of photon RT, device malfunctions occur at ∼3% of RT courses, posing a substantial issue in clinical practice. Malfunctions described in the literature typically consist of transient software disturbances and only seldom manifest as a permanent damage of the device. Through close cooperation between cardiologists and oncologists, a tailored individualized approach might be necessary in this patient group in waiting time for updated international guidelines in the field.

Development of implantable medical devices: from an engineering perspective

From the first pacemaker implant in 1958, numerous engineering and medical activities for implantable medical device development have faced challenges in materials, battery power, functionality, electrical power consumption, size shrinkage, system delivery, and wireless communication. With explosive advances in scientific and engineering technology, many implantable medical devices such as the pacemaker, cochlear implant, and real-time blood pressure sensors have been developed and improved. This trend of progress in medical devices will continue because of the coming super-aged society, which will result in more consumers for the devices. The inner body is a special space filled with electrical, chemical, mechanical, and marine-salted reactions. Therefore, electrical connectivity and communication, corrosion, robustness, and hermeticity are key factors to be considered during the development stage. The main participants in the development stage are the user, the medical staff, and the engineer or technician. Thus, there are three different viewpoints in the development of implantable devices. In this review paper, considerations in the development of implantable medical devices will be presented from the viewpoint of an engineering mind.

50th Anniversary of the first successful permanent pacemaker implantation in the United States: historical review and future directions

June 2010 marks the 50th anniversary of the first successful human cardiac pacemaker implantation in the United States. On June 6, 1960, in Buffalo, New York, Dr. William Chardack implanted a pacemaker, designed and built by Wilson Greatbatch, an electrical engineer and inventor, in a 77-year old man with complete atrioventricular block, extending the patient's life by 18 months. This landmark event ushered in a new era of implantable cardiac pacemakers with batteries and leads of high reliability and increasing durability. Over the past half century, the field of electrophysiology and implantable devices for the management of cardiac conduction disturbances has evolved dramatically. Today's pacemakers include increasingly complex features such as telemetry monitoring, auto programmability, and hemodynamic sensors. New-generation leads present a sophisticated design with improved geometry and steroid-eluting tips to reduce chronic inflammation, maintaining a low pacing threshold and high sensing capability. The lithium iodide battery remains the mainstay of implantable pacemaker systems, exhibiting a multiple-year lifespan, slow terminal decay, and a reduced size and cost of production. Although Greatbatch's first successful pacemaker implantation remains a seminal scientific contribution to modern cardiovascular disease management, emerging developments in this field may challenge its preeminence. Important challenges such as imaging compatibility, lead durability, and infection prevention are being addressed. Novel concepts such as leadless and biologic pacing are under active investigation. In conclusion, Greatbatch's historic achievement 50 years ago reminds us that technologic progress is timeless, as efforts to enhance clinical outcomes and the quality of life continue unimpeded into the 21st century.