First experience with the wearable cardioverter defibrillator in the Netherlands

The implantable cardioverter defibrillator (ICD) has significantly improved survival in patients with an increased risk of sudden cardiac death (SCD). The wearable cardioverter defibrillator (WCD) is an alternative to the ICD in patients with a transient ICD indication or those in whom an ICD temporarily cannot be implanted. We describe here the technical details of the WCD and report three patients who were treated with a WCD in an outpatient setting. The WCD allowed the cardiac condition of two patients to improve to such an extent that permanent ICD implantation was deemed unnecessary. This new form of therapy may result in significant cost reduction, avoidance of unnecessary ICD implantation, and increased patient satisfaction

Complications and Prognosis of Patients Undergoing Apical or Septal Right Ventricular Pacing

Objectives Optimal right ventricular lead placement remains controversial. Large studies investigating the safety and long-term prognosis of apical and septal right ventricular lead placement have been lacking.Methods Consecutive patients undergoing pacemaker insertion for high-degree atrioventricular block at Edinburgh Heart Centre were investigated. Periprocedural 30-day complications were defined (infection/bleeding/pneumothorax/tamponade/lead displacement). Long-term clinical outcomes were obtained from the General Register of Scotland and electronic medical records. The primary endpoint was a composite of all-cause mortality, new heart failure, hospitalisation for a major cardiovascular event, as per the CArdiac REsynchronization in Heart Failure trial. Secondary endpoints were all-cause mortality, new heart failure and their composite.Results 820 patients were included, 204 (25%) paced from the septum and 616 (75%) from the apex. All baseline variables were similar with the exception of age (septal: 73.2±1.1 vs apical: 76.9±0.5 years, p<0.001). Procedure duration (58±23 vs 55±25 min, p=0.3), complication rates (18 (8.8) vs 46 (7.5)%, p=0.5) and postimplant QRS duration (152 (23) vs 154 (27) ms, p=0.4) were similar. After 1041 days (IQR 564), 278 patients met the primary endpoint, with no difference between the septal and apical groups in unadjusted (HR 0.86 (95% CIs 0.64 to 1.15)) or multivariable analysis correcting for age, gender and comorbidity (HR 0.97 (95% CI 0.72 to 1.30)). Similarly, no differences were observed in the secondary endpoints.Conclusions This large real-world cohort of patients undergoing right ventricular lead placement in the septum or apex demonstrated no difference in procedural complications nor long-term clinical outcomes. Both pacing strategies appear reasonable in routine practice

Atrial High-Rate Episode Duration Thresholds and Thromboembolic Risk: A Systematic Review and Meta-Analysis

BACKGROUND: Available evidence supports an association between atrial high‐rate episode (AHRE) burden and thromboembolic risk, but the necessary extent and duration of AHREs to increase the thromboembolic risk remain to be defined. The aim of this systematic review and meta‐analysis was to identify the thromboembolic risk associated with various AHRE thresholds. METHODS AND RESULTS: We searched PubMed and Scopus until January 9, 2020, for literature reporting AHRE duration and thromboembolic risk in patients with implantable electronic devices. The outcome assessed was stroke or systemic embolism. Risk estimates were reported as hazard ratio (HR) or relative risk alongside 95% CIs. We used the Paule‐Mandel estimator, and heterogeneity was calculated with I(2) index. Among 27 studies including 61 919 patients, 23 studies reported rates according to the duration of the longest AHRE and 4 studies reported rates according to the cumulative day‐level AHRE duration. In patients with cardiac implantable devices, AHREs lasting ≥30 seconds significantly increased the risk of stroke or systemic embolism (HR, 4.41; 95% CI, 2.32–8.39; I(2), 5.5%), which remained consistent for the thresholds of 5 minutes and 6 and 24 hours. Patients with previous stroke or transient ischemic attack and AHREs lasting ≥2 minutes had a marginally increased risk of recurrent stroke or transient ischemic attack. The risk of stroke or systemic embolism was higher in patients with cumulative AHRE ≥24 hours compared with those of shorter duration or no AHRE (HR, 1.25; 95% CI, 1.04–1.52; I(2), 0%). CONCLUSIONS: This systematic review and meta‐analysis suggests that single AHRE episodes ≥30 seconds and cumulative AHRE duration ≥24 hours are associated with increased risk of stroke or systemic embolism

A new era for cardiac rhythm management devices:Solutions for transvenous lead complications

Both pacemakers and cardiac defibrillators (ICD) have been designed to treat cardiac arrhythmias. These arrhythmias often lead to life-threatening conditions. Numerous studies have shown the benefits on survival and quality of life of these cardiac rhythm management (CRM) devices. These devices rely on a transvenous intracardiac lead for sensing and to deliver therapy. Unfortunately the lead is the Achilles-heal of this therapy. Most complications of CRM therapy are related to implantation, malfunction or infection of these leads. Some complications even have fatal consequences. This is obviously in contradiction with one of the most important rules in medicine: First Do No Harm!This thesis describes the introduction of three new technologies designed to overcome these complications. In part I the initial experience in The Netherlands is presented with the wearable cardiac defibrillator. In part II the introduction and further widespread use of the subcutaneous ICD is discussed together with chapters on new implantation techniques and on management of inappropriate therapy. In part III the clinical experience with two different leadless pacemakers is being analyzed and in part IV successful animal experiments with a system consisting of an S-ICD communicating with a leadless pacemaker open the door to a new era for cardiac rhythm management. In this new era leads will probably not be necessary anymore to treat cardiac arrhythmias which will lead to less complications and better patient outcome

The application of impantable sensors in the musculoskeletal system: a review

As the population ages and the incidence of traumatic events rises, there is a growing trend toward the implantation of devices to replace damaged or degenerated tissues in the body. In orthopedic applications, some implants are equipped with sensors to measure internal data and monitor the status of the implant. In recent years, several multi-functional implants have been developed that the clinician can externally control using a smart device. Experts anticipate that these versatile implants could pave the way for the next-generation of technological advancements. This paper provides an introduction to implantable sensors and is structured into three parts. The first section categorizes existing implantable sensors based on their working principles and provides detailed illustrations with examples. The second section introduces the most common materials used in implantable sensors, divided into rigid and flexible materials according to their properties. The third section is the focal point of this article, with implantable orthopedic sensors being classified as joint, spine, or fracture, based on different practical scenarios. The aim of this review is to introduce various implantable orthopedic sensors, compare their different characteristics, and outline the future direction of their development and application

experiência de um centro

Introdução: A Insuficiência Cardíaca (IC) é uma doença frequente e com considerável aumento de prevalência, já designada como sendo a epidemia do século XXI. Os doentes com IC manifestam uma alta taxa de mortalidade cardiovascular, em que as arritmias ventriculares malignas estão envolvidas. A remodelagem estrutural e elétrica nos portadores de IC levam a alterações eletromecânicas que desencadeiam a dissincronia cardíaca e natural agravamento da doença, provocando o aumento da predisposição para o aparecimento de arritmias e consequentemente aumento do risco de morte súbita. Objetivo: Caracterização dos doentes com IC seguidos na consulta de ICC do Centro Hospital Leiria-Pombal (CHLP) e avaliação da ocorrência dos eventos cardiovasculares. Avaliação dos parâmetros de repolarização ventricular e o seu contributo no aumento da suscetibilidade a arritmias malignas e/ou morte súbita. Métodos: Selecionou-se um grupo de 130 indivíduos inscritos na consulta externa de ICC-Avançada do CHLP, avaliando-se durante uma média de 42,15 meses de follow-up. Caracterizou-se a amostra quanto aos dados clínicos (anamnese clinica, analises e exames complementares de diagnóstico) e parâmetros de repolarização ventricular (QT, QTc, Tpeack-Tend). Os indivíduos em FA forem classificados quanto ao risco trombótico CHADS2 e CHA2DS2VAS. Quanto aos eventos hospitalares agrupou-se a amostra em Com MACE e Sem MACE. Resultados: Verificou-se que 76,2% da amostra é do sexo masculino, com uma média de idades de 65,9 ±14,8, a etiologia da IC mais comum nesta amostra foi a HTA e a isquémica (n=41 e n=39, respetivamente); segundo a classificação de NYHA 64,6% encontra-se em grau II; 43,1% da amostra encontra-se em FA. Dos 84 indivíduos com avaliação da FEVE, 42,7% tinham a FEVE bastante diminuída e 40,4% depressão ligeira/moderada da FEVE. 10,8% dos indivíduos da amostra foi tratado com ressincronização cardíaca. Durante o follow-up foram registadas 1.479 admissões hospitalares, das quais 1.039 são no serviço de urgência e 182 no serviço de cardiologia. 12,3% da amostra faleceu durante a recolha de dados. A mortalidade total foi influenciada, com significado estatístico (p<0,05), pela idade, QTc, Tpeack-end, total de internamentos, admissões no serviço de urgência, creatinina, ureia e pela TFG. As determinantes independentes para a mortalidade foram a dislipidémia e o total de internamentos, sendo que a idade se revelou tendencialmente significativa. As variáveis TFG, HTA, os antecedentes familiares cardíacos e a terapêutica sem sinvastatina revelaram-se marginalmente significativos para a variável MACE. Os indivíduos com IC mais idosos, com maior percentagem de peso, com diabetes e com alterações na creatinina e TFG revelaram relação estatística com a admissão num dos serviços de internamento. A duração do QRS, do QTC, do Tpeack-Tend e a terapêutica sem anticoagulantes revelaram-se marginalmente significativos na necessidade de internamento hospitalar. Em relação aos doentes em FA segundo a classificação em CHa2DS2VASC e CHADS2 verificou-se que 76,8% da amostra e 48,2% (respetivamente) encontrava-se num score acima do 3. Verificou-se um aumento tendencialmente exponencial em relação ao risco de morte com o aumento do score de CHADS2, bem como a relação direta com o aumento da probabilidade de eventos cardiovasculares. Conclusões: Os portadores de IC são um grupo de doentes peculiares; em que a remodelagem estrutura e elétrica proporciona modificações que culminam no aumento da predisposição para o surgimento de arritmias e consequente aumento de risco de morte súbita

Single event upset testing of flash based field programmable gate arrays

In the last 50 years microelectronics have advanced at an exponential rate, causing microelectronic devices to shrink, have very low operating voltages and increased complexities; all this has made circuits more sensitive to various kinds of failures. These trends allowed soft errors, which up until recently was just a concern for space application, to become a major source of system failures of electronic products. The aim of this research paper was to investigate different mitigation techniques that prevent these soft errors in a Video Graphics Array (VGA) controller which is commonly used in projecting images captured by cameras. This controller was implemented on a Flash Based Field Programmable Gate array (FPGA). A test set-up was designed and implemented at NRF iThemba LABS, which was used to conduct the experiments necessary to evaluate the effectiveness of different mitigation techniques. The set-up was capable of handling multiple Device Under Tests (DUT) and had the ability to change the angle of incidence of each DUT. The DUTs were radiated with a 66MeV proton beam while the monitoring equipment observed any errors that had occurred. The results obtained indicated that all the implemented mitigation techniques tested on the VGA system improved the system’s capability of mitigating Single Event Upsets (SEU). The most effective mitigation technique was the OR-AND Multiplexer Single Event Transient (SET) filter technique. It was thus shown that mitigation techniques are viable options to prevent SEU in a VGA controller. The permanent SEU testing set-up which was designed and manufactured and was used to conduct the experiments, proved to be a practical option for further microelectronics testing at iThemba LABS

Electrospun piezoelectric polymer 3D structures for wearable energy harvesters

Wearable devices have emerged as one of the most rapidly growing branches of the consumer electronics industry in recent years. Having a wide breadth of applications, ranging from leisure and fitness tracking to therapeutics and diagnostics, their development has become a critical driving force in the field of personalised medicine and point-of-care technologies. With the availability of more powerful processing techniques, efficient design approaches, and the miniaturisation of the basic building blocks that conform them, the capabilities of wearable devices have great potential for growth. Energy sources are one of the critical challenges associated with the design of wearable electronics. Renewable sources such as piezoelectric energy harvesters are of great interest, offering a viable alternative that can help tackle the problem of e-waste by enhancing the lifespan of a primary power source or as an independent power source. The piezoelectric active core materials of energy harvesters are the elements that allow for the conversion of mechanical energy to electrical energy. Contrary to the case of using piezoelectric ceramics, polymer based active cores offer superior flexibility, low manufacturing costs, and are non-toxic. However, their piezoelectric properties are comparatively lower than those of ceramics. Micro and nanofabrication methods for the manufacture of polymer based piezoelectric structures are of great interest in the field of energy harvesting because they allow for the tuning of specific morphological properties of these materials, offering the possibility of tailoring the material to the intended application and for the enhancement of the piezoelectric properties of the manufactured structures in some cases, which can bring the piezoelectric performance of polymer based materials closer to that of ceramics Electrospinning is a technique for the fabrication of nano and microfibrous structures based on the principles of electrohydrodynamics. This versatile manufacturing method not only allows for the fabrication of diverse morphologies of a material depending on the working parameters, ambient conditions and reagents, but can also intrinsically enhance the properties of the product. In this thesis, electrospinning will be used for the fabrication of polymer based piezoelectric materials. The work presented in the following chapters will focus firstly on the optimisation of the working parameters and on the composition of the polymer solutions for the fabrication of morphologically stable fibres and consequently will deal with improving the electrical response of these structures when they are used as the active core of a piezoelectric generator. Initial experimental work deals with the optimisation of polymer solutions containing the ferroelectric polymer poly(vinylidene fluoride) (PVDF). Favourable conditions for the fabrication of PVDF nanofibres were identified, and the resulting 2D fibrous mats were used for assembling a first iteration of piezoelectric generators. The findings indicated that the electrospun PVDF product had a favourable electrical response in spite of the morphology of the fibrous product not being ideal. Thus, improving the quality of the electrospun products would certainly allow for the fabrication of better performing generators. The use of chemical additives, solvent systems, and the combination of polymers for electrospinning can heavily influence the quality of the product. This thesis proceeds with the exploration of this premise, using combinations of PVDF with poly(ethylene oxide) (PEO) and lithium chloride (LiCl) for improving the quality of the material. Fibre morphology improved dramatically with the use of these additives, and it was observed that the fabricated fibrous structures could now transition to 3D materials under specific conditions, with variants ranging from a cloud-like structure to thick sponge-like fibrous mats. The conditions required for the production of 3D structures were found to be compatible with poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE), a copolymer known to have intrinsically superior piezoelectric properties than PVDF. The fabricated structures were used for assembling piezoelectric generators, and their electrical properties were shown to be comparable or to outperform similar state-of-the-art devices. Design opportunities were identified while working on the proposed piezoelectric generator architecture and the interfacing methods used for bonding the active core to the electrode materials. The thesis finalises with an exploration of additional methods that can be used to further increase the electrical response of generators with thick sponge-like fibrous PVDF-TrFE/PEO active cores. The findings of this final study revealed that electrode placement and design that conforms to the characteristics of the electrospun fibrous core and the use of electrode materials that can interface with both the surface of the active core and the fibrous network within the core material can improve the electrical output of the generators dramatically. The multidisciplinary work presented in this thesis explored fields ranging from chemistry and materials science to electronics and electrical engineering, laying the ground work upon which new research opportunities for the development of portable renewable energy sources can develop