Open thoracic surgical implantation of cardiac pacemakers in rodents

Genetic engineering and implantable bioelectronics have transformed investigations of cardiovascular physiology and disease. However, the two approaches have been difficult to combine in the same species: genetic engineering is applied primarily in rodents, and implantable devices generally require large animal models. We recently developed several miniature cardiac bioelectronic devices suitable for mice and rats to combine the advantages of molecular tools and implantable devices. Successful implementation of these device-enabled studies requires microsurgery approaches that reliably interface bioelectronics to the beating heart with minimal disruption to native physiology. This protocol describes how to perform an open thoracic surgical technique for epicardial implantation of novel wireless cardiac bioelectronic devices in adult rats and has significantly lower mortality than transvenous implantation approaches. In addition, we provide the methodology for a full biocompatibility assessment of the physiological response to the implanted device. The surgical implantation procedure takes about 40 minutes to complete for an experienced operator, and up to 8 surgeries can be completed in one day. Implanted pacemakers provide programmed electrical stimulation for over 1 month. This protocol has broad applications to enable fully conscious in vivo studies of cardiovascular physiology in transgenic rodent disease models.

Long-Term, Single-Centre Observation of Patients with Cardiac Implantable Electronic Devices

Background and Objectives: Electrotherapy is a valuable treatment method for patients with heart rhythm disturbances. There are very few observations of long-term patients treated with these techniques. There is a particular lack of this type of study conducted in Eastern European countries. The aim of this single-centre analysis was to evaluate the long-term survival (from 2010 to 2018) of patients treated with electrotherapy devices, taking into account clinical factors facilitating the prognosis of these patients. Materials and Methods: The patients (N = 2071) subsequently included in the study were subjected to the implementation or replacement of cardiac pacemakers. The medical records of all the patients were analysed. Data concerning death, made available by the State Systems Department of the Ministry of Administration and Digitization, were used. Results: The patients with VVI pacemakers had the worst prognosis after the replacement of the devices. Male patients had a worse prognosis, regardless of the kind of device implanted. Advanced atrioventricular conduction disturbances, chronic kidney disease, and hypothyroidism with reduced left ventricular ejection fraction were among the most significant coexisting diseases. Conclusions: The long-term prognosis of patients under different forms of electrotherapy remains poor. Despite the more straightforward technique, a single-chamber device (VVI/AAI) or generator replacement leads to the worst prognosis. The complexity of the clinical picture that stems from coexisting diseases and advanced age is of the utmost importance.

Inductive Power Transfer Link at 13.56 MHz for Leadless Cardiac Pacemakers

Inductive power links are most viable for the long-term powering of cardiac pacemakers. Designing an inductive power link without surpassing the specific absorption rate (SAR) for modern leadless cardiac pacemakers (LCPs) remains a challenging task because of its size and implantation depth. The inductive power link employed in the conventional works is either designed at a high frequency or based on the size, shape, weight, and implantation depth of conventional cardiac pacemakers. Here, a 3-coil inductive power transfer link with a circular transmitter coil and solenoidal receiver coil is designed at 13.56 MHz to provide uninterrupted power to the modern LCPs. Considering the food and drug administration approved term for implant size of modern LCP, the receiver coil is designed with 6 mm diameter and 6.5 mm length. The performance of the link has been verified through simulations and measurements under perfect alignment, lateral and/or angular misalignments, and distance variation between the coils. At a 50 mm horizontal distance between transmitter and receiver coils, the transmission coefficient is −30.9 dB. The maximum simulated average SAR at heterogeneous phantom is 0.30 W/kg, which is lower than the limit set by the Federal Communications Commission for radiation threshold exposure. Experiments conducted on pork’s heart verified the reliability of the simulated results. At a 50 mm distance between the coils, the measured transmission coefficient is −34 dB, and at an input power of 1 W, the power delivered to the load is 0.7 mW.

The use of endoscopic cryoapplicator in liver and gallbladder surgery

Purpose of the study. To investigate the efficacy of focal destruction tissues of local liver diseases, chole- and hemostasis of created endoscopic cryoapplicator in operations on the liver and gallbladder.Material and methods. Review the results of surgical treatment of 121 patients with various diseases of the liver (tumors, alveococcosis, parasitic and non-parasitic cysts) and gallbladder (chronic and acute cholecystitis) using a new endoscopic porous TiNi cryoapplicator. 49 patients were operated by an open method, 72 - laparoscopically. Hemo-and cholestatic control of the instrument was performed intraoperative and in postoperative period - by clinical condition of patient and by ultrasonography. Efficiency of destruction of focal liver diseases was investigated by histological examinations of surgical materials, is confirmed by the absence of relapses in the period from 4 to 6 years.The results. Cryoapplicator is simple in use, in sterilization, no energy consumption, can be used both in open surgery, particularly in arduous regions of the liver and laparoscopic procedures and, most importantly, patients with artificial cardiac pacemakers.Cryodestruction of the liver stump after its resection and the bed of the gallbladder after cholecystectomy reduces blood loss by 30-40%, and also helps to reduce the number of relapses of the disease. There were not observed bleeding and bile leakage in postoperative period. Histological examination proved picture of avascular necrosis, a violation of tissue structure of subjected to destruction liver focal diseases, death of epithelial lining of non-parasitic cysts and membranes of echinococcal cysts. There were not diseases recurrences in the period from 4 to 6 years.Conclusion. Endoscopic porous TiNi cryoapplicator is simple and convenient in use, it has a good hemo- and cholestatic effects, pronounced effect to local destruction of liver focal diseases, can be recommended for open and laparoscopic operations on liver.

Electromagnetic Compatibility Issues in Medical Devices

Electromagnetic compatibility (EMC) in biomedical applications is a significant issue related to the user’s life safety, especially in implantable medical devices. Cardiovascular diseases and neurodegenerative disorders are the main chronic disease worldwide that rely on implantable treatment devices such as cardiac pacemakers and vagus nerve stimulators. Both devices must have high EMC to avoid electromagnetic interference-induced health risks, even death during the treatment. Thus, it is important to understand how EMI can affect implantable devices and proactively protect devices from electromagnetic interference, providing reliable and safe implantable device therapy. To this end, this chapter comprehensively introduces the clinical issues and provides EMC requirements for the implantable device such as a cardiac pacemaker and vagus nerve stimulator. The significance of this chapter is to present the EMC important issues in medical engineering that can help to evolve reliable and secure implantable device development in the future.

Tricuspid Valve Replacement in a Patient with a Leadless Cardiac Pacemaker: Current Guidelines and Recommendations for Perioperative Management

Leadless cardiac pacemakers were developed to reduce complications associated with conventional transvenous pacemakers. While this technology is still relatively new, devices are increasingly being implanted. The perioperative management of patients with these devices has been underreported; we thus seek to add to the limited body of knowledge of perioperative management of patients with leadless cardiac pacemakers. An elderly female patient with a Micra VR transcatheter pacing system leadless cardiac pacemaker placed for tachycardia-bradycardia syndrome with intermittent complete heart block was scheduled for elective tricuspid valve replacement for severe tricuspid regurgitation. Pacemaker interrogation was performed several hours prior to the scheduled surgery based on the electrophysiologist’s availability; the device was kept in its programmed VVIR mode, and the base rate was increased from 60 to 80 beats per minute in anticipation of the upcoming surgery. Upon preoperative evaluation, the anesthesiologist asked that the electrophysiology team be placed on standby intraoperatively due to the concern that either oversensing in the setting of pacemaker dependence and/or undesirable tachycardia from rate-responsive pacing could occur. The surgeon used monopolar electrocautery for the duration of the cardiac surgery. Despite the patient having evidence of pacemaker dependence in the intensive care unit preoperatively, no electromagnetic interference leading to oversensing nor rate modulation was detected during intraoperative electrocardiographic and intraarterial invasive monitoring. Evidence-based guidelines regarding perioperative management specifically of leadless cardiac pacemakers do not exist. As these devices become more prevalent, further evaluation will be paramount to determine whether existing guidelines for perioperative management of conventional transvenous pacemakers apply.

Access to MRI for patients with cardiac pacemakers and implantable cardioverter defibrillators

ObjectiveTo determine provision of MRI for patients with cardiac implantable electronic devices (CIEDs; pacemakers and defibrillators) in England, to understand regional variation and assess the impact of guideline changes.MethodsRetrospective data related to MRI scans performed in patients with CIED over the preceding 12 months was collected using a structured survey tool distributed to every National Health Service Trust MRI unit in England. Data were compared with similar data from 2014/2015 and with demand (estimated from local CIED implantation rates and regional population data by sustainability and transformation partnerships (STPs)).ResultsResponses were received from 212 of 223 (95%) hospitals in England. 112 (53%) MRI units’ scan patients with MR-conditional CIEDs (10% also scan non-MR conditional devices), compared with 46% of sites in 2014/2015. Total annual scan volume increased over fourfold between 2014 and 2019 (1090 to 4896 scans). There was widespread geographical variation, with five STPs (total population >3·5 million representing approximately 25 000 patients with CIED) with no local provision. There was no correlation between local demand (CIED implantation rates) and MRI provision (scan volume). Complication rates were extremely low with three events nationally in 12 months (0·06% CIED–MRI scans).ConclusionsProvision of MRI for patients with CIEDs in England increased over fourfold in 4 years, but an estimated 10-fold care gap remains. Almost half of hospitals and 1 in 10 STPs have no service, with no relationship between local supply and demand. Availability of MRI for patients with non-MR conditional devices, although demonstrably safe, remains limited.