Cardiac pacing, 1960-1985: a quarter century of medical and industrial innovation

Minimally invasive power sources for implantable electronics

As implantable medical electronics (IMEs) developed for healthcare monitoring and biomedical therapy are extensively explored and deployed clinically, the demand for non-invasive implantable biomedical electronics is rapidly surging. Current rigid and bulky implantable microelectronic power sources are prone to immune rejection and incision, or cannot provide enough energy for long-term use, which greatly limits the development of miniaturized implantable medical devices. Herein, a comprehensive review of the historical development of IMEs and the applicable miniaturized power sources along with their advantages and limitations is given. Despite recent advances in microfabrication techniques, biocompatible materials have facilitated the development of IMEs system toward non-invasive, ultra-flexible, bioresorbable, wireless and multifunctional, progress in the development of minimally invasive power sources in implantable systems has remained limited. Here three promising minimally invasive power sources summarized, including energy storage devices (biodegradable primary batteries, rechargeable batteries and supercapacitors), human body energy harvesters (nanogenerators and biofuel cells) and wireless power transfer (far-field radiofrequency radiation, near-field wireless power transfer, ultrasonic and photovoltaic power transfer). The energy storage and energy harvesting mechanism, configurational design, material selection, output power and in vivo applications are also discussed. It is expected to give a comprehensive understanding of the minimally invasive power sources driven IMEs system for painless health monitoring and biomedical therapy with long-term stable functions.

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.

Reshaping healthcare with wearable biosensors

Wearable health sensors could monitor the wearer's health and surrounding environment in real-time. With the development of sensor and operating system hardware technology, the functions of wearable devices have been gradually enriched with more diversified forms and more accurate physiological indicators. These sensors are moving towards high precision, continuity, and comfort, making great contributions to improving personalized health care. At the same time, in the context of the rapid development of the Internet of Things, the ubiquitous regulatory capabilities have been released. Some sensor chips are equipped with data readout and signal conditioning circuits, and a wireless communication module for transmitting data to computer equipment. At the same time, for data analysis of wearable health sensors, most companies use artificial neural networks (ANN). In addition, artificial neural networks could help users effectively get relevant health feedback. Through the physiological response of the human body, various sensors worn could effectively transmit data to the control unit, which analyzes the data and provides feedback of the health value to the user through the computer. This is the working principle of wearable sensors for health. This article focuses on wearable biosensors used for healthcare monitoring in different situations, as well as the development, technology, business, ethics, and future of wearable sensors for health monitoring.

The history of cardiac pacing in the young and a look to the future

PURPOSE OF REVIEW

The purpose of this review is to explore the historical and serendipitous events that led to the creation of modern-day pacemakers. In addition, this review will explore how contemporary conduction site-specific pacing has overcome some of the deleterious effects from historical chronic right ventricular apical pacing.

RECENT FINDINGS

Recently, there have been tremendous advances in not just the lead design but the tools required to promote more physiologic pacing. Although cardiac resynchronization pacing has been around for nearly 2 decades, this review also introduces and discusses the early results of His-bundle pacing and left bundle branch pacing and some of the potential applicability of this technology for our children.

SUMMARY

Pacemakers have evolved significantly in the last 30 years through collaborative partnerships between physicians and engineers. The future of cardiac pacing is bright compared to the field of electrotherapy 50 years ago. Future iterations of pacemakers must consider unusual anatomy and growing children. Pediatric patients contribute to a small percentage of the overall device volume, but the majority of these patients will have a pacemaker for life. We need to be proactive and consider what are the best short and long-term solutions for this cohort.

Perioperative complications after pacemaker implantation: higher complication rates with subclavian vein puncture than with cephalic vein cutdown

PURPOSE

The cephalic vein cutdown (CVC) and the subclavian puncture (SP) is the most common access for pacemaker implantation. The purpose of this study was to compare the peri-/postoperative complications of these approaches.

METHODS

A retrospective analysis of the quality assurance data of the state of North Rhine-Westphalia was performed to evaluate the peri-/postoperative complications of first pacemaker implantation according to the venous access. The primary endpoint was defined as the occurrence of one of the following: asystole, ventricular fibrillation, pneumothorax, hemothorax, pericardial effusion, pocket hematoma, lead dislocation, lead dysfunction, postoperative wound infection or other complication requiring intervention. Descriptive analysis was done via absolute, relative frequencies and Odds Ratio. Fisher's exact test was used for comparison of the both study groups.

RESULTS

From 139,176 pacemaker implantations from 2010 to 2014, 15,483 cases were excluded due to other/double access. The median age was 78 years and the access used was CVC for 75,251 cases (60.8%) and SP for 48,442 cases (39.2%). The implanted devices were mainly dual-chamber pacemakers (73.9% in the CVC group and 78.4% in the SP group), followed by single-chamber pacemakers VVI (24.9% and 19.9% in the CVC and SP group respectively). There were significantly fewer peri/postoperative complications in the CVC group compared to the SP group (2.49% vs. 3.64%, p = 0.0001, OR 1.47; 95% CI 1.38-1.57).

CONCLUSIONS

CVC as venous access for pacemaker implantation has significantly fewer peri/postoperative complications than SP and appears to be an advantageous technique.

Effects of the Anode Diffusion Layer on the Performance of a Nonenzymatic Electrochemical Glucose Fuel Cell with a Proton Exchange Membrane

It is necessary to apply a nonenzymatic glucose fuel cell using a proton exchange membrane for an implantable biomedical device that operates at low power. The permeability of glucose with high viscosity and a large molecular weight in the porous medium of the diffusion layer was investigated for use in fuel cells. Carbon paper was prepared as an anode diffusion layer, and it was analyzed with a diffusion layer treated with polytetrafluoroethylene (PTFE) and a microporous layer (MPL). When untreated carbon paper was applied, the peak power density (PPD) and open-circuit voltage (OCV) increased as the glucose concentration and flow rate increased. On this occasion, the highest PPD of 17.81 μW cm^-2 was achieved at 3 mM and a 2.0 mL min^-1 glucose aqueous solution (at atmospheric pressure and 36.5 °C). The diffusion layer, which became more hydrophobic through PTFE treatment, adversely affected glucose permeability. In addition, the addition of an MPL decreased OCV and PPD with increasing glucose concentrations and flow rates. Compared with untreated carbon paper, the PPD was six times lower approximately. Consequently, it was confirmed that the properties of carbon paper, such as low hydrophobicity, high porosity, and thin thickness, would be advantageous for nonenzymatic glucose fuel cells.

Recent Advances of Energy Solutions for Implantable Bioelectronics

The emerging field of implantable bioelectronics has attracted widespread attention in modern society because it can improve treatment outcomes, reduce healthcare costs, and lead to an improvement in the quality of life. However, their continuous operation is often limited by conventional bulky and rigid batteries with a limited lifespan, which must be surgically removed after completing their missions and/or replaced after being exhausted. Herein, this paper gives a comprehensive review of recent advances in nonconventional energy solutions for implantable bioelectronics, emphasizing the miniaturized, flexible, biocompatible, and biodegradable power devices. According to their source of energy, the promising alternative energy solutions are sorted into three main categories, including energy storage devices (batteries and supercapacitors), internal energy-harvesting devices (including biofuel cells, piezoelectric/triboelectric energy harvesters, thermoelectric and biopotential power generators), and external wireless power transmission technologies (including inductive coupling/radiofrequency, ultrasound-induced, and photovoltaic devices). Their fundamentals, materials strategies, structural design, output performances, animal experiments, and typical biomedical applications are also discussed. It is expected to offer complementary power sources to extend the battery lifetime of bioelectronics while acting as an independent power supply. Thereafter, the existing challenges and perspectives associated with these powering devices are also outlined, with a focus on implantable bioelectronics.

Toward nanobioelectronic medicine: Unlocking new applications using nanotechnology

Bioelectronic medicine aims to interface electronic technology with biological components and design more effective therapeutic and diagnostic tools. Advances in nanotechnology have moved the field forward improving the seamless interaction between biological and electronic components. In the lab many of these nanobioelectronic devices have the potential to improve current treatment approaches, including those for cancer, cardiovascular disorders, and disease underpinned by malfunctions in neuronal electrical communication. While promising, many of these devices and technologies require further development before they can be successfully applied in a clinical setting. Here, we highlight recent work which is close to achieving this goal, including discussion of nanoparticles, carbon nanotubes, and nanowires for medical applications. We also look forward toward the next decade to determine how current developments in nanotechnology could shape the growing field of bioelectronic medicine. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Diagnostic Tools > Biosensing.

Evolution of Wearable Devices with Real-Time Disease Monitoring for Personalized Healthcare

Wearable devices are becoming widespread in a wide range of applications, from healthcare to biomedical monitoring systems, which enable continuous measurement of critical biomarkers for medical diagnostics, physiological health monitoring and evaluation. Especially as the elderly population grows globally, various chronic and acute diseases become increasingly important, and the medical industry is changing dramatically due to the need for point-of-care (POC) diagnosis and real-time monitoring of long-term health conditions. Wearable devices have evolved gradually in the form of accessories, integrated clothing, body attachments and body inserts. Over the past few decades, the tremendous development of electronics, biocompatible materials and nanomaterials has resulted in the development of implantable devices that enable the diagnosis and prognosis through small sensors and biomedical devices, and greatly improve the quality and efficacy of medical services. This article summarizes the wearable devices that have been developed to date, and provides a review of their clinical applications. We will also discuss the technical barriers and challenges in the development of wearable devices, and discuss future prospects on wearable biosensors for prevention, personalized medicine and real-time health monitoring.

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.

A review on remote monitoring technology applied to implantable electronic cardiovascular devices

Implantable electronic cardiovascular devices (IECD) include a broad spectrum of devices that have the ability to maintain rhythm, provide cardiac resynchronization therapy, and/or prevent sudden cardiac death. The incidence of bradyarrhythmias and other cardiac problems led to a broader use of IECD, which turned traditional follow-up into an extremely heavy burden for healthcare systems to support. Our aim was to assess the impact of remote monitoring on the follow-up of patients with IECD. We performed a review through PubMed using a specific query. The paper selection process included a three-step approach in which title, abstract, and cross-references were analyzed. Studies were then selected using previously defined inclusion criteria and analyzed according to the country of origin of the study, year, and journal of publication; type of study; and main issues covered. Twenty articles were included in this review. Eighty percent of the selected papers addressed clinical issues, from which 94% referred clinical events identification, clinical stability, time savings, or physician satisfaction as advantages, whereas 38% referred disadvantages that included both legal and technical issues. Forty-five percent of the papers referred patient issues, from which 89% presented advantages, focusing on patient acceptance/satisfaction, and patient time-savings. The main downsides were technical issues but patient privacy was also addressed. All the papers dealing with economic issues (20%) referred both advantages and disadvantages equally. Remote monitoring is presently a safe technology, widely accepted by patients and physicians, for its convenience, reassurance, and diagnostic potential. This review summarizes the principles of remote IECD monitoring presenting the current state-of-the-art. Patient safety and device interaction, applicability of current technology, and limitations of remote IECD monitoring are also addressed. The use of remote monitor should consider the selection of patients, the type of disease, and centers' availability to receive, interpret and respond to device alerts. Before remote IECD monitoring can be routinely used, technical, procedure, and ethical/legal issues should be addressed.

Light induced stimulation and delay of cardiac activity

This article shows the combination of light activatable ion channels and microelectrode array (MEA) technology for bidirectionally interfacing cells. HL-1 cultures, a mouse derived cardiomyocyte-like cell line, transfected with channelrhodopsin were stimulated with a microscope coupled 473 nm laser and recorded with custom built 64 electrode MEAs. Channelrhodopsin induced depolarization of the cell can evoke action potentials (APs) in single cells. Spreading of the AP over the cell layer can then be measured with good spatiotemporal resolution using MEA recordings. The possibility for light induced pacemaker switching in cultures was shown. Furthermore, the suppression of APs can also be achieved with the laser. Possible applications include cell analysis, e.g. pacemaker interference or induced pacemaker switching, and medical applications such as a combined cardiac pacemaker and defibrillator triggered by light. Since current prosthesis research focuses on bidirectionality, this system may be applied to any electrogenic cell, including neurons or muscles, to advance this field.

Diffusion of medical technology: medical devices in India

This review examines the diffusion of modern medical devices in India by analyzing trends in India's cross-border trade in medical devices, its domestic medical device production and utilization by households. We explore the implications of this process of diffusion for the efficacy, cost-effectiveness and equitable use of new medical devices in India, and review recent efforts to regulate the Indian medical device sector.

Selective site pacing: rationale and practical application

Although it has become traditional to place permanent pacemaker leads at the right ventricular apex and right atrial appendage, pacing from these locations poorly mimics normal physiology. A growing evidence base shows that right ventricular apical pacing results in ventricular dyssynchrony and various adverse effects. Provocative data from early trials suggest that pacing from alternate sites in the right ventricle--His bundle pacing, para-Hisian pacing, septal right ventricular outflow tract pacing, and right ventricular midseptal pacing--may lead to improved results. Similarly, early data suggest that right atrial pacing near Bachmann's bundle may lead to superior outcomes when compared with pacing from the right atrial appendage. Several large-scale, randomized clinical trials are now under way to establish the future role of selective site pacing.

Surface stimulation of the brain with a prototype array for a visual cortex prosthesis

We are developing a neural prosthesis to electrically stimulate the visual cortex to restore basic visual perceptions to blind patients. The effects on cortical excitation of different stimulus configurations using a prototype electrode array are presented. Cats underwent a bilateral craniotomy to expose the cortex. An array for brain stimulation was placed on the surface of the right hemisphere. Cortical stimulation was undertaken in a variety of configurations while measuring the evoked responses that propagated through transcallosal pathways, at a homologous region on the contralateral hemisphere. Cortical excitation elicited by stimulation with a particular paradigm could be assessed by measuring the spatial spread and amplitudes of evoked responses in the contralateral hemisphere. Results from this transcallosal model have allowed us to examine the spatial and amplitude effects of cortical stimulation with our prototype electrode array and will aid in developing a neuroprosthesis for blind patients.

Assessment and management of patients with pacemakers and implantable cardioverter defibrillators

OBJECTIVE

To review the design and function of pacemakers and implantable cardioverter defibrillators with particular attention to those aspects that are of clinical relevance to perioperative and critical care physicians.

MAIN POINTS

Pacemakers and implantable cardioverter defibrillators are complex devices that interact with cardiac function in ways that can significantly influence hemodynamics. A basic appreciation of device technology is essential to understanding both the normal patterns of pacemaker and implantable cardioverter defibrillator usage and the ways in which iatrogenic influences may result in adverse outcomes. The most important concern for pacemaker patients who enter the hospital is exposure to electromagnetic interference. Exposure is mainly from surgical cautery, but other sources are also present. With awareness of these concerns and an understanding of how to prevent adverse interactions, it is possible to safely care for these patients in the critical care setting. Despite recommended precautions, undesirable outcomes may occur and the clinician must be prepared to intervene in an appropriate manner to prevent patient injury.

Stretch-induced regional mechanoelectric dispersion and arrhythmia in the right ventricle of anesthetized lambs

Regional mechanical and electrophysiological changes accompany most ventricular arrhythmias and, it has been suggested, by mechanoelectric feedback. We hypothesized that an intervention producing regional mechanical dispersion was associated with regional, proarrhythmic electrical dispersion and studied the regional mechanoelectric feedback in the right ventricle (RV) of anesthetized lambs. Ten lambs were deeply anesthetized, and their hearts were exposed. Three tripodal devices, each incorporating three monophasic action potential electrodes and an integrated strain-gauge system, were placed on the RV apex outflow and inflow regions. Measurements were made before, during, and after 10-s pulmonary arterial occlusion. Pulmonary arterial occlusion increased RV pressure and overall regional segment length. Length excursion became out of phase with RV pressure beats immediately after occlusion, and the strain patterns were different in the three regions at the peak of occlusion. The occlusion resulted in different alterations in regional monophasic action potential morphology, including reduction in monophasic action potential amplitude and duration by different amounts and early afterdepolarizations that were unevenly distributed in the monophasic action potential recordings. This was associated with dispersion of repolarization and recovery time. The combination of electromechanical events precipitated a variety of arrhythmias. Acute RV distension is proarrhythmic, possibly through a causal relationship among mechanically induced afterdepolarizations, dispersion (heterogeneity) of mechanical strain, and dispersion of electrical recovery. The relationship among the different wall motions, the dispersion of repolarization, and arrhythmia underscored mechanoelectric feedback as an important part of arrhythmogenesis in pulmonary embolism and commotio cordis.

Evaluation of the Appropriateness of Pacemaker Mode Selection in Bradycardia Pacing:

Although guidelines for selection of the appropriate pacing mode have been published, little data is available on how closely these are followed in the clinical setting. All 738 patients (men 412, women 326; age 73.4 +/- 0.46 years; range 19-101 years) who underwent pacemaker implantation from 1996 to 2000 were reviewed to determine if the appropriate mode was selected based on the ACC/AHA guidelines with the data collected prospectively. Demographic, investigational, and implantation data including the presence of sinus disease and/or atrioventricular block, diagnosis, indication for pacing, ACC/AHA class indication for device therapy, recommended ACC/AHA mode, implanted mode, and reason for not using the recommended mode were entered into an SPSS data base. Of 738 patients, 708 were cross-tabulated for a match to the guidelines of which 358 (50.6%) had a mode selected that did not conform. The reasons were advanced physical disability (16%), physician choice without identifiable reason (21%), rate modulation selected without identifiable indication (16%), DDD implanted instead of VDD (25%), advanced age (9%), rare need for pacing (6%), a need for specific device features (5%), and unstable stimulation thresholds or difficult venous access (2%). In the treatment of bradyarrhythmias, deviation from the ACC/AHA indicated mode occurred in a substantial proportion of pacing system implantations. However, in many, the deviation appeared appropriate considering the patient's clinical status. Nevertheless, in a smaller proportion of patients the deviation appeared inappropriate requiring rectification. The two outstanding categories were: (1) elderly denied a dual chamber system with no clinical explanation and (2) selection of rate-modulated devices without any indication of chronotropic incompetence.

A systematic approach to pacemaker assessment

Despite the increasing use of pacemaker therapy, assessment of pacemaker function and electrocardiogram (ECG) interpretation continue to challenge even experienced critical care nurses. Accurate assessment of pacemaker function is essential in the evaluation of patients, especially patients with symptoms that may be related to pacemaker malfunction such as syncope or palpitations. This article will review pacing concepts and pacing system components. A systematic approach to ECG interpretation will be presented that can be used in a variety of clinical settings.

Past and future technologic developments for rhythm and conduction disturbances

Since the first cardiac pacemaker was implanted in 1958, continuing technologic innovations have steadily improved the therapeutic power of implantable cardiac device therapy. This evolution has benefited both patients and their physicians, expanding the conditions manageable through pacing and implantable defibrillation while streamlining implant and follow-up procedures. This progress is likely to continue unabated because (1) devices will continue to grow smaller; (2) more advanced features will be introduced, with an increased level of automaticity; and (3) the quality and quantity of telemetered diagnostic information about both patient and device will continue to expand, and device sophistication will soon reach the point at which prediction and prevention of specific events will be a reality. This article reviews historical developments and presents concepts that are guiding future technologic innovations.

Taking advantage of sophisticated pacemaker diagnostics

The ever-increasing complexity of pacing systems, combined with functions that vary from one manufacturer to another, can pose challenges during analysis of device function. Standard pacemaker diagnostics are measured data, electrogram telemetry, maker annotations and event counters, albeit with their current limitations. New diagnostic features discussed include time-based diagnostics, histograms of sensed amplitudes, pacing thresholds, or impedance trending. Mode-switching algorithms, combined with diagnostic features, facilitate the use of dual-chamber devices in patients with paroxysmal atrial tachyarrhythmias. The introduction of electrogram storage into pacemakers further improves diagnostic capabilities and allows a permanent validation and optimization of diagnostic and therapeutic algorithms. External diagnostic devices, which provide Holter recordings with continuous marker annotations and patient-triggered diagnostics, are additional features that will become increasingly important.