[How to: Basics of programming cardiac pacemakers]. / How to: Basics der Schrittmacherprogrammierung.

Programming of implantable cardiac devices, especially dual-chamber pacemakers, can be challenging in daily clinical practice. Precise knowledge of programmable parameters is important; furthermore, one should also be familiar with the specific algorithms of each manufacturer. During programming, the patient's individual requirements should be taken into account, but out-of-the-box programming should be avoided. Another important goal of programming should be to stimulate as much as needed but as little as possible to provide the patient good exercise capacity while not being aware of the pacing. Manufacturers' algorithms can help reach these aims but need to be understood and-in case of inappropriate behavior-to be deactivated.

Coexistence of deep brain stimulators and cardiac implantable electronic devices: A systematic review of safety.

As the number of patients implanted with deep brain stimulation systems increases, coexistence with cardiac implantable electronic devices (CIEDs) poses questions about safety. We systematically reviewed the literature on coexisting DBS and CIED. Eighteen reports of 34 patients were included. Device-device interactions were reported in 6 patients. Sources of complications were extensively reviewed and cautious measures which could be considered as part of a standard checklist for careful consideration are suggested.

Cybersecurity: The need for data and patient safety with cardiac implantable electronic devices.

Remote monitoring of cardiac implantable electronic devices (CIEDs) has become routine practice as a result of the advances in biomedical engineering, the advent of interconnectivity between the devices through the Internet, and the demonstrated improvement in patient outcomes, survival, and hospitalizations. However, this increased dependency on the Internet of Things comes with risks in the form of cybersecurity lapses and possible attacks. Although no cyberattack leading to patient harm has been reported to date, the threat is real and has been demonstrated in research laboratory scenarios and echoed in patient concerns. The CIED universe comprises a complex interplay of devices, connectivity protocols, and sensitive information flow between the devices and the central cloud server. Various manufacturers use proprietary software and black-box connectivity protocols that are susceptible to hacking. Here we discuss the fundamentals of the CIED ecosystem, the potential security vulnerabilities, a historical overview of such vulnerabilities reported in the literature, and recommendations for improving the security of the CIED ecosystem and patient safety.

Permanent pacemaker implantation rates following cardiac surgery in the modern era.

AIMS: The aim of this study was to evaluate the incidence of permanent pacemaker (PPM) implantation after cardiac surgery in our institution and investigate risk factors for PPM dependency to provide patients with accurate incidence figures at the time of consent for surgery. METHODS: Data was collected retrospectively from a single tertiary institution from October 2018 to April 2019 inclusive of 403 patients. Incidence of PPM implantation after various cardiac operations was evaluated. A univariate analysis was carried out to identify the independent risk factors related to PPM implantation. RESULTS: Ten patients required a PPM (2.48%). The most common indication for PPM implantation post-cardiac surgery was complete heart block (N = 7, 70%) followed by bradycardia/pauses (N = 2, 20%) and sick sinus syndrome (N = 1, 10%). PPM implantation after coronary artery bypass graft (CABG) surgery was the lowest (0.63%), while combined CABG and valve operations had the highest incidence (5.97%). Independent risk predictors for PPM implantation included female gender (p = 0.03), rheumatic heart disease (p = 0.008), pulmonary hypertension (p = 0.01), redo operations (p = 0.002), mitral valve procedures (p = 0.001), tricuspid valve procedures (p = 0.0003) and combined mitral and tricuspid valve procedures (p = 0.0001). Average length of intensive care unit (ICU)/high-dependency unit (HDU) stay was significantly prolonged for patients who required a PPM post-cardiac surgery. CONCLUSION: As clinicians, it can be challenging to provide our patients with accurate information on the risk of PPM implantation relative to their operation. A unit-specific data may be a more accurate method of informing our patients on this risk.

Implante de marcapasos transitorio en una terapia intensiva municipal / Implantation of temporary pacemaker in a municipal intensive care unit

Introducción: Las bradi-arritmias son cardiopatías graves que ocasionan trastornos hemodinámicos severos; llevar al paciente a un gasto cardiaco normal puede implicar que se implante un marcapasos. Objetivo: Describir algunos aspectos clínicos y epidemiológicos de pacientes que recibieron la técnica de implantar un marcapasos. Métodos: Se realizó un estudio descriptivo y transversal, con 36 pacientes que necesitaron marcapasos transitorio, ingresados en la unidad de cuidados intensivos del Hospital General Docente "Orlando Pantoja Tamayo" de Contramaestre, en el período desde octubre de 2015 hasta mayo de 2019. Las variables utilizadas fueron: grupo de edades y sexo, causas de arritmias y antecedentes patológicos personales, medicamentos más usados previos al ingreso, tiempo de uso del marcapasos transitorio y necesidad de implantación del permanente. Resultados: Predominó el sexo masculino y edades de 80 y más años, el trastorno de la conducción auriculoventricular más frecuente fue el bloqueo auriculoventricular de tercer grado; el tiempo promedio de uso de marcapaso transitorio fue entre 2 y 6 días. Conclusiones: La implantación precoz en esta entidad municipal mejoró notablemente la supervivencia de los pacientes(AU)

Introduction: Bradyarrhythmias are serious heart diseases that cause severe hemodynamic disorders. Bringing the patient to normal cardiac output may imply that a pacemaker be implanted. Objective: To describe some clinical and epidemiological aspects of patients who received the technique of implanting a pacemaker. Methods: A descriptive and cross-sectional study was carried out with 36 patients who needed a temporary pacemaker, admitted to the intensive care unit of Orlando Pantoja Tamayo General Teaching Hospital in Contramaestrem, in the period from October 2015 to May 2019. The variables used were age group and sex, causes of arrhythmias, and personal pathological history, most used medications prior to admission, time of usage of the temporary pacemaker, and the need for permanent implantation. Results: The male sex and ages 80 and older predominated, the most frequent atrioventricular conduction disorder was the third-degree atrioventricular block. The average time of temporary pacemaker usage was between two and six days. Conclusions: Early implantation in this municipal institution significantly improved patient survival(AU)

Cardiac Magnetic Resonance Imaging (MRI) in Children is Safe with Most Pacemaker Systems, Including Those with Epicardial Leads.

Magnetic resonance imaging (MRI) of patients with pacemakers remains concerning because of possible magnetic field effects on the device. Many pacemaker models are labeled as non-conditional, or contraindicated for MRI, or do not have any specific safety guidelines listed. This study describes our experience with pacemaker function and adverse events in pediatric and young adult patients after clinically indicated MRI scanning at 1.5 Tesla (T). We hypothesized that generator battery voltage, pacemaker lead threshold, and lead impedance would not be altered by MRI. This was a retrospective review of Children's Wisconsin clinical MRI data for all patients with pacemakers scanned between January 1, 2010 and March 31, 2018. Pacemakers were interrogated by the Electrophysiology Team before and immediately after MRI and at outpatient follow up. Twenty-one patients underwent forty-four MRI scans. No significant immediate changes were seen in any pacemaker parameter for any manufacturer/model/lead at the time of MRI. At first clinical follow up post MRI, (median 4.4 months, range 0.2-12.3), battery voltage was reduced (2.78 V pre-MRI versus 2.77 V at follow up, p = 0.02), but there were no other significant changes. No adverse events were noted. Pediatric patients with pacemakers, including those with epicardial leads, can be scanned at 1.5 T safely without alteration in pacemaker function. Using appropriate precautions, pediatric patients with pacemakers can be imaged with MRI.

Attack Graph Modeling for Implantable Pacemaker.

Remote health monitoring systems are used to audit implantable medical devices or patients' health in a non-clinical setting. These systems are prone to cyberattacks exploiting their critical vulnerabilities. Thus, threatening patients' health and confidentiality. In this paper, a pacemaker automatic remote monitoring system (PARMS) is modeled using architecture analysis and design language (AADL), formally characterized, and checked using the JKind model checker tool. The generated attack graph is visualized using the Graphviz tool, and classifies security breaches through the violation of the security features of significance. The developed attack graph showed the essentiality of setting up appropriate security measures in PARMS.

Investigation into the effect of transcranial direct current stimulation on cardiac pacemakers.

BACKGROUND: Studies investigating the therapeutic applications of transcranial direct current stimulation (tDCS) in the treatment of age-related neurodegenerative disease have been promising. However, exclusion criteria for these studies invariably disqualify patients implanted with internal cardiac pacemakers, citing safety concerns. Because the majority of cardiac pacemaker implantees are over 65, this criterion may limit candidacy for tDCS based research and/or treatment of age-related neurodegenerative disease. OBJECTIVE/HYPOTHESIS: We will test the hypothesis that tDCS impacts pacemaker function. Strong electrical potentials, such as those generated by external defibrillators (∼500 V, ∼10 A), are known to occasionally damage pacemaker circuitry and software, but it seems unlikely tDCS would damage a pacemaker because it involves about 1/200th the energy (∼12 V, ∼2 mA) of an external defibrillator. METHODS: We delivered tDCS to seven participants (ages 70-92) with bipolar non-dependent pacemakers and subsequently collected data from the internal memory of the pacemakers to assess the tDCS signal detection, as well as alterations in mode switches, impedance levels, and pacing. Subsequently, similar assessments were carried out in participants who were pacemaker-dependent (ages 89-91). RESULTS: After a review of the recordings, it was found that tDCS had no impact on the non-dependant, as well as the dependent, pacemakers. There were zero mode switches nor any impact on impedance levels. CONCLUSION: Results in this small series of cases found no evidence that tDCS interferes with the function of the pacemakers and suggests tDCS can be delivered to patients equipped with a cardiac pacemaker. Further studies are needed to generalize these results to other pacemakers.

Closing the Loop: Validation of Implantable Cardiac Devices With Computational Heart Models.

OBJECTIVE: Cardiovascular Implantable Electronic Devices (CIEDs) are used extensively for treating life-threatening conditions such as bradycardia, atrioventricular block and heart failure. The complicated heterogeneous physical dynamics of patients provide distinct challenges to device development and validation. We address this problem by proposing a device testing framework within the in-silico closed-loop context of patient physiology. METHODS: We develop an automated framework to validate CIEDs in closed-loop with a high-level physiologically based computational heart model. The framework includes test generation, execution and evaluation, which automatically guides an integrated stochastic optimization algorithm for exploration of physiological conditions. CONCLUSION: The results show that using a closed loop device-heart model framework can achieve high system test coverage, while the heart model provides clinically relevant responses. The simulated findings of pacemaker mediated tachycardia risk evaluation agree well with the clinical observations. Furthermore, we illustrate how device programming parameter selection affects the treatment efficacy for specific physiological conditions. SIGNIFICANCE: This work demonstrates that incorporating model based closed-loop testing of CIEDs into their design provides important indications of safety and efficacy under constrained physiological conditions.

Subclinical and Device-Detected Atrial Fibrillation: Pondering the Knowledge Gap: A Scientific Statement From the American Heart Association.

The widespread use of cardiac implantable electronic devices and wearable monitors has led to the detection of subclinical atrial fibrillation in a substantial proportion of patients. There is evidence that these asymptomatic arrhythmias are associated with increased risk of stroke. Thus, detection of subclinical atrial fibrillation may offer an opportunity to reduce stroke risk by initiating anticoagulation. However, it is unknown whether long-term anticoagulation is warranted and in what populations. This scientific statement explores the existing data on the prevalence, clinical significance, and management of subclinical atrial fibrillation and identifies current gaps in knowledge and areas of controversy and consensus.

[Design of Cardiac Pacemaker Based on Low Power MCU].

In order to improve the accuracy of the pacemaker's parameter adjustment and to avoid the surgical replacement of the pacemaker when the battery is exhausted, this paper designs a novel single-chamber pacemaker circuit based on low-power single-chip microcomputer. The circuit uses digital control to accurately control the amplitude, pulse width and frequency of the pacing pulse. The circuit is also designed with wireless charging function, and wireless communication with the programmer can wirelessly charge the pacemaker and know the charging information in real time. Wireless charging function can reduce the number of times the patient replaces the pacemaker or even completely avoid it.

Worsening of Mitral Regurgitation by Balloon Aortic Valvuloplasty for Severe Aortic Stenosis.

A 91-year-old woman was admitted to our hospital for treatment of congestive heart failure with severe aortic stenosis. After admission, she developed a high fever due to pneumonia and worsened heart failure. We could not perform transcatheter aortic valve implantation (TAVI) because of active infection; therefore, retrograde balloon aortic valvuloplasty (BAV) was urgently performed. A complete atrioventricular block and severe functional mitral regurgitation appeared suddenly after BAV in the absence of mechanical disorders. Her condition improved after several days in our intensive care unit. Pacemaker implantation and TAVI were then performed, and the patient was discharged from our hospital. MR could sometimes exacerbate after BAV in clinical practice; therefore, we set out to report this case.

Influence of electrical stimulation therapy on permanent pacemaker function.

BACKGROUND: Electrical stimulation therapy (EST) and transcutaneous electrical neuromuscular stimulation (TENS), a modality of EST, have become widely applied, accepted and effective methods for the treatment of musculoskeletal and other pain conditions. According to the rising number of permanent pacemaker (PM) wearers the number of potential candidates for EST with concomitant device implantation is growing. Contradictory recommendations exist regarding the application of EST or TENS on PM wearers. AIM: The study was carried out to evaluate the impact of EST on PM function. METHODS: A full size model mimicking the electrical characteristics of the human body was used to evaluate the application of EST on permanent PM devices. Various configurations with respect to energy modality, position of the stimulation electrodes and PM device models were evaluated. Intracardiac PM electrogram tracings (iEGM) were analyzed for the interference of EST with PM function. RESULTS: Unilateral EST application did not cause interference with PM function in any of the configurations (0%; n = 700). On the contrary, bilateral stimulation (350 configurations in total) caused either ventricular inhibition or switch to V00 back-up pacing due to electrical interference in 165 cases (47.1%) depending on the applied stimulation parameters. CONCLUSION: The use of EST potentially interferes with PM therapy, especially if the electrodes are positioned bilaterally; however, unilateral EST application appeared to be safe in all tested configurations.

Radiation Therapy-Induced Dysfunction in Cardiovascular Implantable Electronic Devices.

PURPOSE: The prevalence of patients with cardiovascular implantable electronic devices (CIEDs) who receive radiation treatment for cancer is increasing. External beam radiation therapy (RT) can affect the electronic components. This study aimed to evaluate the incidence and predictors of new onset CIED dysfunction in patients treated with RT. METHODS AND MATERIALS: We retrospectively analyzed data from 230 patients with CIEDs who received radiation treatment at the Radiation Oncology Center of CHU de Québec - Université Laval between February 2007 and November 2013. The reviewed data included baseline characteristics, CIEDs, and RT treatment specifications. Patients with CIEDs were analyzed before, during, and at the end of radiation treatment. High- and low-energy photon or electron beam radiation from linear accelerators, orthovoltage machines, and high-dose rate brachytherapy delivery were used. Abnormal events could be one of the following: total or partial deprogramming of the CIED parameters, onset of new symptoms, or new arrhythmia. RESULTS: This study is based on one of the largest cohorts. A total of 18 events in 16 patients (7.8%) were recorded. Of the 18 events, 16 had at least part of the radiation treatment delivered with photo neutrons producing high-energy RT (neutron producing RT). Only 2 abnormal events occurred during non-neutron producing RT. Both the prescription dose and the dose estimated at the location of the pacemaker were correlated with the probability of an abnormal event (P = .0006 and P = .003, respectively). Among the 16 patients, clinical symptoms were noted in only 1 patient (6.3%). CONCLUSIONS: CIED malfunctions are relatively uncommon and do not seem to be life threatening. We recommend limiting the dose at the CIED and avoid neutron-producing RT to reduce the risk of CIED malfunction.

Cardiac pacemakers: a basic review of the history and current technology.

In the 60 years since the first human implant of a cardiac pacemaker, tremendous improvements have been made to devices themselves as well as the lead systems. Improvement in battery materials has allowed for production of smaller devices with greater longevity and a vast array of technologies allowing for communication between the device and the operator. Lead wires, typically to as the weakest part of the pacing system, have also seen a metamorphosis as improvements in conductor materials and hybrid insulation have been shown to improve reliability. With the recent development of leadless pacing systems, the downfalls of implantable leads can be avoided. These improvements have allowed a more widespread use of cardiac pacing in veterinary applications since the first reported canine implant in 1967.

Electromagnetic Interference with Protocolized Electrosurgery Dispersive Electrode Positioning in Patients with Implantable Cardioverter Defibrillators.

WHAT WE ALREADY KNOW ABOUT THIS TOPIC: Electromagnetic interference from monopolar electrosurgery may disrupt implantable cardioverter defibrillators.Current management recommendations by the American Society of Anesthesiologists and Heart Rhythm Society are based on expert clinical opinion since there is a paucity of data regarding the risk of electromagnetic interference to implantable cardioverter defibrillators during surgery. WHAT THIS ARTICLE TELLS US THAT IS NEW: With protocolized electrosurgery dispersive electrode positioning in patients with implantable cardioverter defibrillators, the risk of clinically meaningful electromagnetic interference was 7% in above-the-umbilicus noncardiac surgery and 0% in below-the-umbilicus surgery. In cardiac surgery, clinically meaningful electromagnetic interference with use of an underbody dispersive electrode was 29%.Despite protocolized dispersive electrode positioning, the risk of electromagnetic interference in above-the-umbilicus surgery is high, supporting recommendations to suspend antitachycardia therapy when monopolar electrosurgery is used above the umbilicus.With protocolized dispersive electrode positioning, the risk of electromagnetic interference in below-the-umbilicus surgery is negligible, implying that suspending antitachycardia therapy might be unnecessary in these cases.With an underbody dispersive electrode, the risk of electromagnetic interference in cardiac surgery is high. BACKGROUND: The goal of this study was to determine the occurrence of intraoperative electromagnetic interference from monopolar electrosurgery in patients with an implantable cardioverter defibrillator undergoing surgery. A protocolized approach was used to position the dispersive electrode. METHODS: This was a prospective cohort study including 144 patients with implantable cardioverter defibrillators undergoing surgery between May 2012 and September 2016 at an academic medical center. The primary objectives were to determine the occurrences of electromagnetic interference and clinically meaningful electromagnetic interference (interference that would have resulted in delivery of inappropriate antitachycardia therapy had the antitachycardia therapy not been programmed off) in noncardiac surgeries above the umbilicus, noncardiac surgeries at or below the umbilicus, and cardiac surgeries with the use of an underbody dispersive electrode. RESULTS: The risks of electromagnetic interference and clinically meaningful electromagnetic interference were 14 of 70 (20%) and 5 of 70 (7%) in above-the-umbilicus surgery, 1 of 40 (2.5%) and 0 of 40 (0%) in below-the-umbilicus surgery, and 23 of 34 (68%) and 10 of 34 (29%) in cardiac surgery. Had conservative programming strategies intended to reduce the risk of inappropriate antitachycardia therapy been employed, the occurrence of clinically meaningful electromagnetic interference would have been 2 of 70 (2.9%) in above-the-umbilicus surgery and 3 of 34 (8.8%) in cardiac surgery. CONCLUSIONS: Despite protocolized dispersive electrode positioning, the risks of electromagnetic interference and clinically meaningful electromagnetic interference with surgery above the umbilicus were high, supporting published recommendations to suspend antitachycardia therapy whenever monopolar electrosurgery is used above the umbilicus. For surgery below the umbilicus, these risks were negligible, implying that suspending antitachycardia therapy is likely unnecessary in these patients. For cardiac surgery, the risks of electromagnetic interference and clinically meaningful electromagnetic interference with an underbody dispersive electrode were high. Conservative programming strategies would not have eliminated the risk of clinically meaningful electromagnetic interference in either noncardiac surgery above the umbilicus or cardiac surgery.