Transcatheter Non-Acute Retrieval of the Tines-Based Leadless Ventricular Pacemaker.

OBJECTIVES: We report our single-center experience of mid-term to long-term retrieval and reimplantation of a tines-based leadless pacemaker (Micra transcatheter pacing system; TPS). BACKGROUNDS: The TPS is a clinically effective alternative to transvenous single-chamber ventricular pacemakers. Whereas it is currently recommended to abandon the TPS at the end of device life, catheter-based retrieval may be favorable in specific scenarios. METHODS: We report on nine consecutive patients with the implanted TPS who subsequently underwent transcatheter retrieval attempts. The retrieval system consists of the original TPS delivery catheter and an off-the-shelf single-loop 7 mm snare. The procedure was guided by fluoroscopy and intracardiac echocardiography. RESULTS: After an implantation duration of 3.1 ± 2.8 years (range 0.4-9.0), the overall retrieval success rate was 88.9% (8 of 9 patients). The mean procedure time was 89 ± 16 minutes, and fluoroscopy time was 18.0 ± 6.6 min. No procedure-related adverse device events occurred. In the one unsuccessful retrieval, intracardiac echocardiography revealed that the TPS was partially embedded in the ventricular tissue surrounding the leadless pacemaker body in the right ventricle. After retrieval, three patients were reimplanted with a new TPS device. All implantations were successful without complications. CONCLUSIONS: A series of transvenous late retrievals of implanted TPS devices demonstrated safety and feasibility, followed by elective replacement with a new leadless pacing device or conventional transvenous pacing system. This provides a viable end-of-life management alternative to simple abandonment of this leadless pacemaker.

Leadless cardiac ventricular pacing using helix fixation: Step-by-step guide to implantation.

INTRODUCTION: Leadless cardiac pacemakers are an alternative modality to traditional transvenous pacemaker systems. Recently receiving Food and Drug Administration approval, the AVEIR VR leadless pacemaker system provides a helix based active fixation leadless pacemaker system. This step-by-step review will cover patient selection, preprocedural planning, device implantation technique, implant site evaluation, troubleshooting, short- and long-term complications as well as future directions for leadless pacing. METHODS: We collected and reviewed cases from primary operators to provide a step-by-step review for implanters. RESULTS: Our paper provides a guide to patient selection, pre-procedural planning, device im plantation technique, implant site evaluation, troubleshooting, short- and long-term complications as well as future directions for leadless pacing. CONCLUSION: The helix based active fixation leadless pacemaker system is a safe and efficacious way to provide pacing support to patients and provides an alternative to transvenous pacing systems. Our review provides a step-by-step guide to implantation.

Advanced helix-fixation leadless cardiac pacemaker implantation techniques to improve success and reduce complications.

INTRODUCTION: Leadless cardiac pacemakers (LCPs) are becoming more commonly utilized because of their potential advantages (i.e., reduced short and long-term complications, improved patient comfort) and may be the preferred option for patients with venous access problems, high-risk for infection, previous lead fractures, or skin erosion. There are currently two types of LCP fixation mechanisms that have been FDA approved-Medtronic's Micra system has a tine-based fixation and Abbott's Aveir system has a helix-fixation design. This article highlights important tips and tricks for a successful implant of a helix-fixation LCP, particularly when difficulties are encountered, and provides precautions to avoid potential complications. METHODS: Cases of single chamber Aveir LCP implantation were reviewed to highlight examples of procedural pitfalls and suggested methods to circumnavigate them. RESULTS: There are unique procedural considerations regarding the Aveir LCP implant as well as challenges that that may be occasionally encountered. Techniques to address these-such as avoiding air embolism, maneuvering difficult entry into the right ventricle, handling complicated positioning/repositioning, evaluating proper fixation, and releasing difficult tethers-are illustrated in detail. Advice to reduce risks of perforation and to position optimally for potential retrieval and communication for dual chamber pacing are also described. CONCLUSIONS: The advanced teaching concepts described and emphasized in this article may help improve success and prevent procedural complications, especially when physicians are learning how implant these novel helix-fixation LCPs.

Quantification of artifacts during cardiac magnetic resonance in patients with leadless Micra pacemakers.

INTRODUCTION: When cardiac magnetic resonance (MR) is performed after previous leadless transcatheter pacemaker implantation, an image distortion has to be expected in the heart region and evaluation of myocardial tissue can be affected. In this clinical prospective study, we aim to assess the extent and impact of this artifact on individual ventricular segments and compare it to conventional pacing devices. METHODS: Total of 20 patients with leadless pacemaker placed in the right ventricle underwent cardiac MR imaging in a 1.5 Tesla scanner. A multiplanar segmentation was used to demarcate the left and right ventricular myocardium as well as the pacemaker-caused image artifact in systolic and diastolic time frames. Artifact size and its relative influence on myocardial segments were quantitatively assessed and expressed in AHA-17 model. RESULTS: Implanted leadless pacemaker caused an image artifact with a volume of 48 ± 5 ml. Most distorted were the apical septal (53 ± 23%), apical inferior (30 ± 18%), and midventricular inferoseptal (30 ± 20%) segments. The artifact intersection with basal and lateral segments was none or negligible (up to 2%). The portion of left ventricular (LV) myocardium affected by the artifact was significantly higher in systole (8 ± 4%) compared to diastole (10 ± 3%; p < .001). CONCLUSION: Implantation of leadless pacemaker represents no obstacle for cardiac MR imaging but causes an image artifact located mostly in septal, inferoseptal, and anteroseptal segments of apical and midventricular LV myocardium. With the exception of the apex, diastolic timing reduces the image distortion of all segments and improves global ventricular assessment.

Peri-procedural management, implantation feasibility, and short-term outcomes in patients undergoing implantation of leadless pacemakers: European Snapshot Survey.

The aim of this European Heart Rhythm Association (EHRA) prospective snapshot survey is to assess procedural settings, safety measures, and short-term outcomes associated with implantation of leadless pacemakers (LLPM), across a broad range of tertiary European electrophysiology centres. An internet-based electronic questionnaire (30 questions) concerning implantation settings, peri-procedural routines, complications, and in-hospital patient outcomes was circulated to centres routinely implanting both LLPMs and transvenous pacemakers (TV-PM). The centres were requested to prospectively include consecutive patients implanted with either LLPMs or TV-PMs during the 10-week enrolment period. Overall, 21 centres from four countries enrolled 825 consecutive patients between November 2018 and January 2019, including 69 (9%) implanted with LLPMs. Leadless pacemakers were implanted mainly under local anaesthesia (69%), by an electrophysiologist (60%), in the electrophysiology laboratory (71%); 95% of patients received prophylactic antibiotics prior to implantation. Most patients on chronic oral anticoagulation were operated on-drug (35%), or during short-term (to 48 h) drug withdrawal (54%). Implantation was successful in 98% of patients and the only in-hospital procedure-related complication was groyne haematoma in one patient. This EHRA snapshot survey provides important insights into LLPM implantation routines and patient outcomes. These findings suggest that despite the unfavourable clinical profile of pacemaker recipients, LLPM implantation is associated with relatively low risk of complications and good short-term outcomes.

Safety and efficacy of leadless pacemaker retrieval.

BACKGROUND AND OBJECTIVES: The success rate of leadless cardiac pacemaker (LP) retrieval remains a major concern for this disruptive technology. The present paper performed a systematic review of the safety and feasibility of the retrieval of LPs. METHODS: Primary publications that performed LP retrieval were collected and included five animal experiments and two worldwide retrieval experiences in human. The procedural details, such as indication, days post implantation, extraction success rate, and complications, were described. The present paper analyzed factors affecting the retrieval and management of the nonfunctional devices. RESULTS: Retrieval animal models was possible at least up to 2.5 years post implantation, and data from humans suggest that removal of a device that was implanted longer (eg, 4 years and 9 months for Nanostim; 4 years for Micra) could be performed within a reasonable safety profile. The fixed mechanism, implant site, and encapsulation of the LP systems may affect the retrieval process. CONCLUSIONS: A high success rate in the relatively chronic retrieval of LPs was demonstrated, which promotes the extensive use of these devices in the treatment arrhythmia in the future.

Real-world experience with leadless cardiac pacing.

BACKGROUND: Leadless cardiac pacing (LCP) has emerged as a new modality for permanent pacing. We sought to describe comparative outcomes between LCP and transvenous pacemakers. METHODS: Patients receiving LCP (Micra [Medtronic, Minneapolis, MN, USA] and Nanostim [St. Jude Medical/Abbott Laboratories, Chicago, IL, USA]) between 2014 and 2017 at the Mayo Clinic Heart Rhythm Enterprise practice (Rochester, MN, USA; Jacksonville, FL, USA; and Scottsdale, AZ, USA) were identified. We identified 1:1 age- and sex-matched controls receiving single-chamber transvenous ventricular pacemakers (TVP). Statistical analyses were performed with JMP 13.0.0 (SAS, Institute Cary, NC, USA). RESULTS: Ninety patients underwent LCP implantation (73 Micra and 17 Nanostim) with a median follow-up duration of 62 (interquartile range 28-169) days. Both groups had 100% successful device implant rates. There were no differences in procedure-related major (0% vs 1%) or minor complications (8% vs 3%) in the LCP versus TVP groups (P > 0.05). Excluding Nanostim patients, there was a lower rate of device-related revision or extraction in the Micra versus TVP groups (0% vs 5%, P = 0.028). Device endocarditis was more common in the TVP group (0% vs 3%, P = 0.04). Estimated longevity was greater for the LCP group (median 12.0 vs 10.0 years, P < 0.0001). An increase in severity of tricuspid valve regurgitation (TR) by ≥2 grades occurred in none of the LCP patients, and in 19% of the TVP patients (P = 0.017). CONCLUSION: There are no significant differences in procedural complications among patients receiving LCP versus TVP. The Micra group had lower rates of device-related revision/extraction compared to the TVP group. Patients with leadless pacemaker were less likely to develop endocarditis or worsening TR.

Meta-analysis of the incidence of lead dislodgement with conventional and leadless pacemaker systems.

INTRODUCTION: Leadless cardiac pacemaker (LCP) implantation using a transcatheter was recently developed to avoid pocket- and lead-related complications. Although a LCP has an active fixation mechanism using tines or a helix, LCP and lead dislodgement issues remain a major safety concern for patients. This article reviews the literature to determine the incidence of lead and LCP dislodgement. METHODS AND RESULTS: A total of 18 studies which included 17,321 patients undergoing conventional single- or dual-chamber pacemaker implantation and three studies which included 2,116 patients undergoing LCP device implantation were reviewed. The incidence of lead dislodgement ranged from 1% to 2.69% in individual studies with a mean of 1.63%, weighted mean of 1.71%, and median of 1.60 %. There was a relatively higher lead dislodgement rate between atrial and ventricular electrodes (odds ratio [OR], 3.56; 95% confidence interval [CI], 1.9-6.70; P  =  0.6; I2   =  0%), and between magnetic resonance imaging conditional and conventional leads (OR, 2.79; 95% CI, 1.30-5.99; P  =  0.16; I2   =  46%). The use of active fixation leads (OR, 1.06; 95% CI, 0.66-1.70; P  =  0.29; I2   =  20%) showed no significant difference in dislodgement risk compared to passive fixation leads. The incidence of LCP device dislodgement was 0%, 0.13%, and 1% in three leadless pacemaker studies. CONCLUSIONS: The incidence rates of conventional pacemaker lead dislodgement vary in individual studies with an overall high incidence. Use of the currently available LCP systems appears to result in a lower rate of device dislodgement. This may reflect the effectiveness of this novel technology and the fixation design of LCP devices.

Monocentric experience of leadless pacing with focus on challenging cases for conventional pacemaker.

AIM: Leadless cardiac pacemaker has been developed to reduce complications related to cardiac pacing and is considered as an alternative to conventional pacemaker although safety and efficacy data in clinical practice are limited. The purpose of this study was to investigate the safety and efficacy profile of Micra Transcatheter Pacing System (TPS) used in daily clinical activity with a focus on challenging cases for conventional pacing. METHODS: A total of 66 patients (46 men, 79.1 ± 9.7 years) having a Class I or II indication for ventricular pacing underwent a Micra TPS implant procedure. All patients were enrolled in a prospective registry. Follow-up visits were scheduled at discharge and after 1, 3, 6 and 12 months. RESULTS: Primary indication for pacing was third degree atrioventricular block (30.3%), sinus node dysfunction (21.2%) or permanent atrial fibrillation with bradycardia (45.5%). The device was successfully implanted in 65 patients (98.5%). During follow-up of 10.4 ± 6.1 months (range 1-23 months), electrical measurements remained stable. Mean pacing capture threshold, pacing impedance and R-wave sensing were respectively 0.57 ± 0.32 V, 580 ± 103 Ohms, 10.62 ± 4.36 mV at the last follow-up. One major (loss of function) and three minor adverse events occurred. Pericardial effusion, dislodgement, device related infection or pacemaker syndrome were not observed. Micra TPS implantation was straightforward for patients with congenital or acquired cardiac and/or vascular abnormalities, previous tricuspid surgery and after heart transplantation. CONCLUSION: Our experience confirms that implantation of Micra is safe and efficient in a real world population including patients who present a challenging condition for conventional pacing.

Experimental Phantom-Based Security Analysis for Next-Generation Leadless Cardiac Pacemakers.

With technological advancement, implanted medical devices can treat a wide range of chronic diseases such as cardiac arrhythmia, deafness, diabetes, etc. Cardiac pacemakers are used to maintain normal heart rhythms. The next generation of these pacemakers is expected to be completely wireless, providing new security threats. Thus, it is critical to secure pacemaker transmissions between legitimate nodes from a third party or an eavesdropper. This work estimates the eavesdropping risk and explores the potential of securing transmissions between leadless capsules inside the heart and the subcutaneous implant under the skin against external eavesdroppers by using physical-layer security methods. In this work, we perform phantom experiments to replicate the dielectric properties of the human heart, blood, and fat for channel modeling between in-body-to-in-body devices and from in-body-to-off-body scenario. These scenarios reflect the channel between legitimate nodes and that between a legitimate node and an eavesdropper. In our case, a legitimate node is a leadless cardiac pacemaker implanted in the right ventricle of a human heart transmitting to a legitimate receiver, which is a subcutaneous implant beneath the collar bone under the skin. In addition, a third party outside the body is trying to eavesdrop the communication. The measurements are performed for ultrawide band (UWB) and industrial, scientific, and medical (ISM) frequency bands. By using these channel models, we analyzed the risk of using the concept of outage probability and determine the eavesdropping range in the case of using UWB and ISM frequency bands. Furthermore, the probability of positive secrecy capacity is also determined, along with outage probability of a secrecy rate, which are the fundamental parameters in depicting the physical-layer security methods. Here, we show that path loss follows a log-normal distribution. In addition, for the ISM frequency band, the probability of successful eavesdropping for a data rate of 600 kbps (Electromyogram (EMG)) is about 97.68% at an eavesdropper distance of 1.3 m and approaches 28.13% at an eavesdropper distance of 4.2 m, whereas for UWB frequency band the eavesdropping risk approaches 0.2847% at an eavesdropper distance of 0.22 m. Furthermore, the probability of positive secrecy capacity is about 44.88% at eavesdropper distance of 0.12 m and approaches approximately 97% at an eavesdropper distance of 0.4 m for ISM frequency band, whereas for UWB, the same statistics are 96.84% at 0.12 m and 100% at 0.4 m. Moreover, the outage probability of secrecy capacity is also determined by using a fixed secrecy rate.

Early performance of a miniaturized leadless cardiac pacemaker: the Micra Transcatheter Pacing Study.

AIMS: Permanent cardiac pacing is the only effective treatment for symptomatic bradycardia, but complications associated with conventional transvenous pacing systems are commonly related to the pacing lead and pocket. We describe the early performance of a novel self-contained miniaturized pacemaker. METHODS AND RESULTS: Patients having Class I or II indication for VVI pacing underwent implantation of a Micra transcatheter pacing system, from the femoral vein and fixated in the right ventricle using four protractible nitinol tines. Prespecified objectives were >85% freedom from unanticipated serious adverse device events (safety) and <2 V 3-month mean pacing capture threshold at 0.24 ms pulse width (efficacy). Patients were implanted (n = 140) from 23 centres in 11 countries (61% male, age 77.0 ± 10.2 years) for atrioventricular block (66%) or sinus node dysfunction (29%) indications. During mean follow-up of 1.9 ± 1.8 months, the safety endpoint was met with no unanticipated serious adverse device events. Thirty adverse events related to the system or procedure occurred, mostly due to transient dysrhythmias or femoral access complications. One pericardial effusion without tamponade occurred after 18 device deployments. In 60 patients followed to 3 months, mean pacing threshold was 0.51 ± 0.22 V, and no threshold was ≥2 V, meeting the efficacy endpoint (P < 0.001). Average R-wave was 16.1 ± 5.2 mV and impedance was 650.7 ± 130 ohms. CONCLUSION: Early assessment shows the transcatheter pacemaker can safely and effectively be applied. Long-term safety and benefit of the pacemaker will further be evaluated in the trial. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov ID NCT02004873.

Feasibility, timing and outcome of leadless cardiac pacemaker implantation in patients undergoing cardiac implantable electronic device extraction.

BACKGROUND: Patients requiring extraction of infected or dysfunctional cardiac implantable electronic devices (CIED) have high morbidity and mortality. The Micra™ leadless cardiac pacemaker (LCP) may be beneficial for patients requiring permanent pacemaker therapy after CIED extraction. METHODS: This study aimed to assess the feasibility, timing and outcomes of LCP implantation in patients who underwent CIED extraction due to infection or dysfunction. The local Micra™ LCP registry was reviewed for LCP implantations and CIED extractions. RESULTS: Micra™ LCP implantation was scheduled for 48 consecutive patients (21 women, 44%) undergoing CIED extraction for infection (n = 38, 79%) or dysfunction (n = 10, 21%), and feasible in 47 (98%). Complete CIED removal was feasible in 44 patients (92%) and in 37/38 patients with infected CIED (97%). Overall, 32 LCP (67%) were implanted in a single procedure: 3 (6%) before and 13 (27%) after CIED extraction. LCP were implanted in a single procedure in 24/38 patients (63%) with infected CIED and in 8/10 patients (80%) with dysfunctional CIED. The in-hospital mortality rate was 6% (n = 3), and the survival rates at 30 days, 90 days and 1 year were 94% (n = 45/48), 90% (n = 43/48), and 85% (n = 41/48), respectively. No recurrent LCP-related mortality or infections occurred during a median follow-up of 15 (interquartile range, 12-41) months. CONCLUSION: Two-thirds of LCPs could be implanted in a single procedure with CIED extraction; no recurrent infections were detected. Overall, Micra™ LCP implantation in patients requiring CIED extraction was feasible.

Long-Term Safety and Efficacy of Intraoperative Leadless Pacemaker Implantation During Valve Surgery.

BACKGROUND: Intraoperative implantation of leadless cardiac pacemakers (LCPs) under direct visualization during cardiac surgery is a novel strategy to provide pacing to patients with an elevated risk of postoperative conduction disorders or with a preexisting pacing indication undergoing valve surgery. OBJECTIVES: This study sought to evaluate the long-term safety and efficacy of intraoperative LCP implantation in 100 consecutive patients. METHODS: Retrospective single-center cohort study of consecutive patients (n = 100) who underwent intraoperative LCP implantation during valve surgery. Safety and efficacy were assessed at implantation and follow-up visits. RESULTS: A total of 100 patients (age 68 ± 13 years, 47% female) underwent intraoperative LCP implantation. The surgery involved the tricuspid valve in 99 patients (99%), including tricuspid valve repair in 59 (59%) and tricuspid valve replacement in 40 (40%). Most of the patients (78%) underwent multivalve surgery. The indication for LCP implantation was elevated risk of postoperative atrioventricular block in 54% and preexisting bradyarrhythmias in 46%. LCP implantation was successful in all patients. During a median of 10.6 months (IQR: 2.0-22.7 months) of follow-up, no device-related complications occurred. At 12-month follow-up, the pacing thresholds were acceptable (≤2.0 V at 0.24 milliseconds) in 95% of patients. CONCLUSIONS: Intraoperative LCP implantation under direct visualization is a safe strategy to provide permanent pacing in patients undergoing valve surgery, with a postoperative electrical performance comparable to percutaneously placed LCPs.

Leadless AV Pacemaker in Patient with Complete Heart Block and Bilaterally Implanted Two Deep Brain Stimulators Can Be Safe Therapeutic Option.

There are reports documenting that electromagnetic waves generated by deep brain stimulation devices can interfere with cardiac pacemakers. This might be even a life-threatening problem in cardiac pacemaker-dependent patients. Herein, we present a case report on a patient with bilaterally implanted deep brain stimulation devices, who concomitantly had the indications for permanent cardiac pacing. The report shows that a leadless AV pacemaker may be a safe and reasonable option in these cases.

New Insights in Central Venous Disorders. The Role of Transvenous Lead Extractions.

Over the last decades, the implementation of new technology in cardiac pacemakers and defibrillators as well as the increasing life expectancy have been associated with a higher incidence of transvenous lead complications over time. Variable degrees of venous stenosis at the level of the subclavian vein, the innominate trunk and the superior vena cava are reported in up to 50% of implanted patients. Importantly, the number of implanted leads seems to be the main risk factor for such complications. Extraction of abandoned or dysfunctional leads is a potential solution to overcome venous stenosis in case of device upgrades requiring additional leads, but also, in addition to venous angioplasty and stenting, to reduce symptoms related to the venous stenosis itself, i.e., the superior vena cava syndrome. This review explores the role of transvenous lead extraction procedures as therapeutical option in case of central venous disorders related to transvenous cardiac leads. We also describe the different extraction techniques available and other clinical indications for lead extractions such as lead infections. Finally, we discuss the alternative therapeutic options for cardiac stimulation or defibrillation in case of chronic venous occlusions that preclude the implant of conventional transvenous cardiac devices.

Retrieval of Long-Term Implanted Leadless Pacemakers: A Single-Center Experience.

OBJECTIVES: The authors report their single-center experience with the retrieval and replacement of long-term implanted leadless cardiac pacemakers (LPs) and the factors contributing to success. BACKGROUND: LPs are a clinically effective and safe alternative to standard transvenous pacemakers for single-chamber ventricular pacing. However, the feasibility of retrieving and replacing long-term implanted LPs is not well known. METHODS: A total of 34 patients with implanted Nanostim LPs (mean implantation duration 1,570 ± 479 days) subsequently underwent retrieval. On the basis of fluoroscopic imaging, the cohort was divided into 2 groups: those with remarkable swinging movement (SM) of the LP docking button (n = 25) and those without SM (n = 9). RESULTS: The overall LP retrieval success rate was 85% (n = 29). New leadless devices were implanted in 27 patients immediately after LP retrieval. No procedure-related adverse events occurred. The rate of successful LP retrieval was significantly higher in the SM group (25 of 25 [100%]) than in the no-SM group (4 of 9 [44%]) (p < 0.001), and fluoroscopy time during the retrieval procedure was shorter in the SM group (12.7 ± 8.6 min) than in the no-SM group (45.6 ± 19 min) (p < 0.001). CONCLUSIONS: This study demonstrated the feasibility and safety of retrieval of long-term implanted LPs after a mean duration of 4 years. Retrieval was most successful in patients whose docking buttons exhibited significant SM.

Complications of leadless vs conventional (lead) artificial pacemakers - a retrospective review.

BACKGROUND: Leadless pacemakers (LPM) are introduced in cardiovascular market with a goal to avoid lead- and pocket-associated complications due to conventional artificial pacemakers (CPM). The comparison of LPM and CPM complications is not well studied at a case by case level. METHODS: Comprehensive literature was searched on multiple databases performed from inception to December 2019 and revealed 204 cases that received LPM with a comparison of CPM. The data of complications were extracted, screened by independent authors and analyzed using IBM SPSS Statistics for Windows, Version 22.0 (Armonk, NY: IBM Corp.). RESULTS: The complications of CPM were high in comparison to LPM in terms of electrode dislodgement (56% vs 7% of cases, p-value < .0001), pocket site infection rate (16% vs 3.4%, p-value = 0.02), and a lead fracture rate (8% vs 0%, p-value = 0.04). LPMs had a statistically non-significant two-times high risk of pericardial effusion (8%) compared to CPMs (4%) with a p-value = 0.8. CONCLUSION: LPMs appear to have a better safety profile than CPMs. There was a low pocket site and lead-related infections in LPM as compared to CPM. However, LPM can have twice the risk of pericardial effusion than CPMs, but this was not statistically significant.

Successful Retrieval of a 4-Year-Old Micra Transcatheter Pacemaker System in a Patient With Leadless Biventricular Pacing Therapy.

This is the first report of the management of a patient with cardiac resynchronization therapy using leadless biventricular pacing. Successful retrieval of a 4-year-old Micra transcatheter pacing system (TPS) and reimplantation of a new Micra TPS prevented device-to-device interactions from multiple pacing devices in the right ventricle. (Level of Difficulty: Advanced.).