Biotelemetry and Wireless Powering for Leadless Pacemaker Systems (original) (raw)
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Leadless pacemakers – The path to safer pacing?
Indian Heart Journal
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Arrhythmia & Electrophysiology Review, 2011
Pacemaker technologies have advanced dramatically over the decades since they were first introduced, and every year many thousands of new implants are performed worldwide. However, there continues to be a high incidence of acute and chronic complications, most of which are linked to the lead or the surgical pocket created to hold the device. A leadless pacemaker offers the possibility of bypassing these complications, but requires a catheter-based delivery system and a means of retrieval at the end of the device’s life, as well as a way of repositioning to achieve satisfactory pacing thresholds and R waves, a communication system and low peak energy requirements. A completely self-contained leadless pacemaker has recently been developed, and its key characteristics are discussed, along with the results of an efficacy and safety trial in an animal model. The results of the LEADLESS study, the first human trial to look at safety and feasibility of the leadless device, are discussed an...
Leadless Cardiac Pacing: New Horizons
Cardiology and Therapy, 2022
Since the introduction of transvenous cardiac pacing leads, pacemaker system design has remained similar for several decades. Progressive miniaturisation of electronic circuitry and batteries has enabled a smaller, single pacing unit comprising the intracardiac electrodes, generator and computer. This review explores the development of leadless pacing, the clinical trials comparing leadless to transvenous pacing in addition to the future developments of multichamber leadless pacing.
Ultra-Compact Implantable Antenna With Enhanced Performance for Leadless Cardiac Pacemaker System
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 2021
Advancement in the technology of leadless cardiac pacemakers (LCPs) has led to ultracompact designs of implantable antennas. In this study, a small-sized antenna for integration with an LCP, which can be operated in the industrial, scientific, and medical (ISM) band of 2.4 GHz, is developed. The proposed antenna was constructed in a spiral shape to provide superior miniaturization, less sensitivity to body tissue variation, and low specific absorption rate (SAR) values, and avoid fabrication complexities due to its small size. The antenna with a footprint of 3 × 4 × 0.5 mm 3 was constructed on a high dielectric material, namely, Rogers RT/duroid 6010. To the best of the authors' knowledge, this is the smallest footprint with enhanced performance when compared to previous reports related to implantable antennas. In addition, the antenna was integrated with a 3-D printed LCP having dummy electronics and experimentally validated in saline solution and minced pork. The antenna sustained good impedance matching at the ISM band with a measured bandwidth of 21.88% and 15.46% with the device and without the device, respectively. Due to the smooth electric field (surface currents) over the patch, the antenna system had 270.28 and 31.04 W/kg peak SAR for 1 and 10 g of tissues, respectively, with a maximum peak gain of −25.95 dBi. We also discussed the effects of a coaxial cable and the antenna orientation on its performance. From the measured received signal strength, a stable biotelemetric link can be established between the implant and external controlling device up to a distance of 2 m.
IEEE Antennas and Wireless Propagation Letters
In this letter, the in-body and off-body channel models at the frequency of 2.4 GHz are studied for development of multi-node leadless capsule pacemaker technology based on experiments in homogeneous liquid phantom model of human heart and living animal experiments. For conducting the experiments, we design a battery-operated self-contained transmitter capsule consisting of a small antenna and transmitter printed-circuit board, sub-cutaneous implant and the off-body antennas. The in-body path-loss model obtained from the phantom experiment is a linear function of distance, whereas the off-body path-loss model between the implant and the off-body antenna is a logarithmic function of distance comparable to the free-space path-loss model. The phantom experiment study shows that coupling between implants decreases linearly at the rate of 3.6 dB/cm for cardiac implants and by 4.1 dB/cm for cardiac to sub-cutaneous implant at 2.4 GHz. The animal experiment results are in good accordance with the phantom results.
Journal of Cardiovascular Electrophysiology, 2018
Introduction: 15-30% of patients with impaired cardiac function have ventricular dyssynchrony and warrant cardiac resynchronization therapy (CRT). While leadless pacemakers eliminate lead related complications, their current form factor is limited to single chamber pacing. In this study, we demonstrate the feasibility of multisite, simultaneous pacing using miniaturized pacing nodes powered through wireless power transfer (WPT). Methods: A wireless energy transfer system was developed based on resonant coupling at approximately 200 MHz to power multiple pacing nodes. The pacing node is comprised of circuitry to efficiently convert the harvested energy to output stimuli. To validate the use of these pacing nodes, ex vivo studies were carried out on Langendorff rodent heart models (n=4). To mimic biventricular pacing, two beating Langendorff rodent heart models, kept 10 cm apart, were paced using two distinct pacing nodes, each attached on the ventricular epicardial surface of a given heart. Results: All ex vivo Langendorff heart models were successfully paced with a simple coil antenna at 2-3 cm from the pacing node using 198MHz and 0.3W. Subsequently, simultaneous pacing of two Langendorff heart models 30 cm apart using an output power of 5W was reliably demonstrated. Conclusion: Wireless power transfer provides a feasible option for multi-site, wireless cardiac pacing. While the current system remains limited in design, it offers support and a conceptual framework for future iterations and eventual clinical utility.
Percutaneous Implantation of an Entirely Intracardiac Leadless Pacemaker
New England Journal of Medicine, 2015
BACKGROUND Cardiac pacemakers are limited by device-related complications, notably infection and problems related to pacemaker leads. We studied a miniaturized, fully self-contained leadless pacemaker that is nonsurgically implanted in the right ventricle with the use of a catheter. METHODS In this multicenter study, we implanted an active-fixation leadless cardiac pacemaker in patients who required permanent single-chamber ventricular pacing. The primary efficacy end point was both an acceptable pacing threshold (≤2.0 V at 0.4 msec) and an acceptable sensing amplitude (R wave ≥5.0 mV, or a value equal to or greater than the value at implantation) through 6 months. The primary safety end point was freedom from device-related serious adverse events through 6 months. In this ongoing study, the prespecified analysis of the primary end points was performed on data from the first 300 patients who completed 6 months of follow-up (primary cohort). The rates of the efficacy end point and safety end point were compared with performance goals (based on historical data) of 85% and 86%, respectively. Additional outcomes were assessed in all 526 patients who were enrolled as of June 2015 (the total cohort). RESULTS The leadless pacemaker was successfully implanted in 504 of the 526 patients in the total cohort (95.8%). The intention-to-treat primary efficacy end point was met in 270 of the 300 patients in the primary cohort (90.0%; 95% confidence interval [CI], 86.0 to 93.2, P = 0.007), and the primary safety end point was met in 280 of the 300 patients (93.3%; 95% CI, 89.9 to 95.9; P<0.001). At 6 months, device-related serious adverse events were observed in 6.7% of the patients; events included device dislodgement with percutaneous retrieval (in 1.7%), cardiac perforation (in 1.3%), and pacing-threshold elevation requiring percutaneous retrieval and device replacement (in 1.3%). CONCLUSIONS The leadless cardiac pacemaker met prespecified pacing and sensing requirements in the large majority of patients. Device-related serious adverse events occurred in approximately 1 in 15 patients. (Funded by St. Jude Medical; LEADLESS II ClinicalTrials .gov number, NCT02030418.