Device Upgrade Research Articles

Procedural and long-term outcomes of tunneled transvenous leads

BackgroundLead-related venous stenosis and occlusion can complicate the insertion or replacement of transvenous leads in patients with cardiac implantable electronic devices (CIEDs). A possible solution is to tunnel the lead from the contralateral vasculature to the ipsilateral generator. Procedural complications and long-term outcomes remain unclear with this technique. ObjectiveWe sought to assess outcomes of tunneled transvenous leads. MethodsWe retrospectively identified all patients who underwent transvenous CIED lead tunneling to a contralateral pocket at our institution between 2014 and 2024. Clinical characteristics, indications for lead implantation, postoperative complications, and long-term outcomes were collected. ResultsWe identified that 27 patients underwent transvenous lead tunneling at our institution. Most patients were men (20, 74%) with a mean age of 68.8 ± 18.3 years. Most patients had nonischemic cardiomyopathy (16, 59%) with a mean ejection fraction of 29.3% ± 11.3%. The tunneled leads were coronary sinus leads (20, 74%), followed by defibrillator leads (5, 18.5%) and right ventricular pacing leads (2, 7.4%). Implantation procedures were primarily for device upgrade (18), lead revisions (8), or de novo lead placement (1). No postoperative complications were seen. Patients were followed for a mean of 2.2 ± 1.4 years. One tunneled defibrillator lead (3.7%) had low shock impedance 3 years after implantation, which was monitored and did not require an intervention. ConclusionIn patients with ipsilateral venous occlusion, contralateral lead tunneling appears to be an effective and safe approach to manage patients with CIEDs and occluded ipsilateral subclavian veins.

Simulation of hemispherical cathode-based linear plasma propulsion device upgrade

Simulation of hemispherical cathode-based linear plasma propulsion device upgrade

Deep septal pacing for pacemaker-induced cardiomyopathy

Abstract Background Conventional right ventricular pacing can impair left ventricular function and cause heart failure, known as pacing induced cardiomyopathy (PICM). Upgrade to cardiac resynchronization therapy (CRT) is the most common treatment for PICM. Recently, left bundle branch area pacing (LBBAP) has emerged as a potential alternative both to conventional RV pacing and to CRT. In Deep septal pacing (DSP), a simplified alternative to LBBAP, the lead is inserted deep in the septum, does not reach the subendocardial area, but is still able to achieve narrower paced QRS than during conventional pacing. Purpose The aim of this study was to assess the effect of DSP in a cohort of patients with PICM. Methods We included consecutive patients diagnosed with PICM who were referred to our unit between January 2020 and January 2022 for a device upgrade. The aim was to upgrade patients to DSP. In the absence of terminal R wave in V1, the procedure was considered successful if a paced QRS duration ≤140 ms was obtained. Clinical and device follow-up were performed one and 6 months after the procedure, and echocardiography at 6 months. The study was approved by the Clinical Research Ethics Committee and all patients signed informed consent. Results Fifteen patients were recruited during the study period. One patient was excluded because a QRS ≤ 140 ms could not be achieved, and 2 other patients because a terminal R wave in paced QRS in V1 was obtained. The characteristics of the 12 included cases are detailed in Table 1. The mean LVEF was 33% (SD 4%) and the mean percentage of RV pacing was 99% (SD 1%). All patients had symptomatic heart failure. Non stylet-driven electrodes were used in 8 of the 12 patients. Acute threshold was < 1V - 0’4 ms in all, and remained stable during follow-up. No procedure-related complications or lead dislodgements were detected. The mean paced QRS duration with RV pacing was 172 ms (SD 14 ms) whereas after the upgrade it was 130 ms (SD 7 ms). As compared to RV pacing, DSP was associated with a significant reduction in paced QRS duration (mean difference 41 ms, p<0.001). As shown in Table 1, after DSP all patients except one (11/12, 92%) experienced an increase in LVEF of at least 10%; five patients (42%) achieved an LVEF>50%. The mean LVEF after the upgrade was 46% (SD 9%). The mean improvement in LVEF with DSP was 13% (SD 10%). Conclusions In patients with PICM, deep septal pacing achieves narrower QRS as compared to RV pacing and is associated with a significant improvement in LVEF. Deep septal pacing might be an effective and simpler alternative to biventricular or left bundle branch pacing in patients with PICM.Table 1

Feasibility and outcomes of ultrasound-guided transcutaneous access to the axillary vein for implantation, revision, and upgrade of cardiac electronic devices

Abstract Background Implanting leads for cardiac implantable electronic devices (CIED) requires venous access. Venous access is commonly established through the cephalic and subclavian vein. For CIED upgrades or revisions, the preferred cephalic vein access is often not viable. Several reports suggest that fluoroscopy-guided axillary vein puncture may reduce thoracic complications. Purpose This study reports on procedural outcomes of ultrasound-guided axillary vein access for CIED implantation, revision, or upgrade in a large tertiary care centre. Outcomes were compared to the traditional subclavian vein approach. Methods This retrospective, single-center non-randomized study, conducted from January 2021 to August 2023, analyzed patients undergoing CIED implantation, revision, or upgrade. Axillary access, initially introduced by one operator, was increasingly adapted by additional operators. The axillary access was obtained by ultrasound-guided visualization of the axillary vein at the deltopectoral groove (Figure 1A and B). Subsequently, the wire(s) were transcutaneously inserted. An adjacent skin incision allowed for threading the wire(s) followed by standard lead implantation (Figure 1C). The study evaluated the acute success of each venous access method and the incidence of adverse events. Those were defined as pneumothorax, hemothorax, and pocket hematoma. An intention-to-treat analysis was performed. A p-value assessed the comparative outcomes between the axillary and subclavian access methods. Results In this study, 986 patients (mean age 74, IQR 64-82 years, 35% women) underwent CIED implantation, revision, or upgrade with 1636 lead implants. Axillary access was used in 578 patients with 532 (92%) successful implantations. Subclavian access yielded a higher success rate with 394/408 patients (97%) (p=0.003). For device upgrades or revisions specifically, axillary access was successful in 68/79 patients (86%), versus 44/47 patients (94%) with subclavian access (p=0.193). Acute complications were less frequent with axillary access (0.3%, 2/578 patients) and consisting of two cases of pneumothorax requiring intervention. In CIED implantations via subclavian access, complications occurred in 17/408 patients (4.2%) (p<0.001) including pneumothorax in 12 patients (2.9%, with 2% requiring intervention), hemothorax in three patients (0.7%), and pocket hematoma in two patients (0.5%). No additional complications were observed in the axillary group. Conclusion The implementation of transcutaneous, ultrasound-guided axillary access for CIED implantations, revisions and upgrades in a major CIED training centre is feasible. Complication rates were low compared to subclavian venous access.Figure 1

DECAF cross-device characterization of tokamak disruptions indicated by abnormalities in plasma vertical position and current

Abnormal (deviating from the target) variations in the plasma vertical position Z and current Ip (such as vertical displacements, transient Ip ‘spikes’ and quenches) constitute common elements of a disruption, a phenomenon that is to be mitigated, or ultimately avoided in future reactor-relevant tokamaks. While these abnormalities are generally recognized cross-shot and cross-device, details in terms of appearance (or not) and order of these abnormalities in disruption event chains (DEC) are bound to the plasma state at the time of the chain initiation. Detection of these abnormalities is thus indicative not only of the onset of the plasma collapse itself but also of the disruption driving cause that is promoted at a particular plasma state. Here, the occurrence of disruptions, explored via the detection of an Ip quench, and the analysis of DEC constituted by Ip and Z abnormalities is reported for in total seven full device-year pairs of operation of three machines (4, 2 and 1 years of KSTAR, MAST-U and NSTX-U operation, respectively) using the DECAF code expanded tools and capabilities. It is shown that the disruption occurrence depends not only on the details of the plasma state but also on (device-dependent) technical elements of the shot exit scenario. Year-to-year changes in the main disruption causes and a reduction in the disruptivity rate, bound by device and operation upgrades, are reported. Particular trigger instances of DEC (and the full chains when applicable) are shown to occupy different parts of the operation space diagrams, in accordance with prior expectations. Plasma elongation is identified as an important factor influencing details of the chains and its role will be further explored.

Factors associated with cardiac implantable electronic device-related infections, New South Wales, 2016-21: a retrospective cohort study.

To quantify the rate of cardiac implantable electronic device (CIED)-related infections and to identify risk factors for such infections. Retrospective cohort study; analysis of linked hospital admissions and mortality data. All adults who underwent CIED procedures in New South Wales between 1 January 2016 and 30 June 2021 (public hospitals) or 30 June 2020 (private hospitals). Proportions of patients hospitalised with CIED-related infections (identified by hospital record diagnosis codes); risk of CIED-related infection by patient, device, and procedural factors. Of 37 675 CIED procedures (23 194 men, 63.5%), 500 were followed by CIED-related infections (median follow-up, 24.9 months; interquartile range, 11.2-40.8 months), including 397 people (1.1%) within twelve months of their procedures, and 186 of 10 540 people (2.5%) at high risk of such infections (replacement or upgrade procedures; new cardiac resynchronisation therapy with defibrillator, CRT-D). The overall infection rate was 0.50 (95% confidence interval [CI], 0.45-0.54) per 1000 person-months; it was highest during the first month after the procedure (5.60 [95% CI, 4.89-6.42] per 1000 person-months). The risk of CIED-related infection was greater for people under 65 years of age than for those aged 65-74 years (adjusted hazard ratio [aHR], 1.71; 95% CI, 1.32-2.23), for people with CRT-D devices than for those with permanent pacemakers (aHR, 1.46; 95% CI, 1.02-2.08), for people who had previously undergone CIED procedures (two or more v none: aHR, 1.51; 95% CI, 1.02-2.25) or had CIED-related infections (aHR, 11.4; 95% CI, 8.34-15.7), or had undergone concomitant cardiac surgery (aHR, 1.62; 95% CI, 1.10-2.39), and for people with atrial fibrillation (aHR, 1.33; 95% CI, 1.11-1.60), chronic kidney disease (aHR, 1.54; 95% CI, 1.27-1.87), chronic obstructive pulmonary disease (aHR, 1.37; 95% CI, 1.10-1.69), or cardiomyopathy (aHR 1.60; 95% CI, 1.25-2.05). Knowledge of risk factors for CIED-related infections can help clinicians discuss them with their patients, identify people at particular risk, and inform decisions about device type, upgrades and replacements, and prophylactic interventions.

Long-term outcomes with abandoning versus extracting sterile leads: A 10-year population-based study.

Long-term outcomes of sterile lead management strategies of lead abandonment (LA) or transvenous lead extraction (TLE) remain unclear. We performed a retrospective study of a population residing in southeastern Minnesota with follow-up at the Mayo Clinic and its health systems. Patients who underwent LA or TLE of sterile leads from January 1, 2000, to January 1, 2011, and had follow-up for at least 10 years or until their death were included. A total of 172 patients were included in the study with 153 patients who underwent LA and 19 who underwent TLE for sterile leads. Indications for subsequent lead extraction arose in 9.1% (n=14) of patients with initial LA and 5.3% (n=1) in patients with initial TLE, after an average of 7 years. Moreover, 28.6% of patients in the LA cohort who required subsequent extraction did not proceed with the extraction, and among those who proceeded, 60% had clinical success and 40% had a clinical failure. Subsequent device upgrades or revisions were performed in 18.3% of patients in the LA group and 31.6% in the TLE group, with no significant differences in procedural challenges (5.2%vs. 5.3%).There was no difference in 10-year survival probability among the LA group and the TLE group (p=.64). An initial lead abandonment strategy was associated with more complicated subsequent extraction procedures compared to patients with an initial transvenous lead extraction strategy. However, there was no difference in 10-year survival probability between both lead management approaches.

Leadless pacemakers at 5-year follow-up: the Micra transcatheter pacing system post-approval registry.

Prior reports have demonstrated a favourable safety and efficacy profile of the Micra leadless pacemaker over mid-term follow-up; however, long-term outcomes in real-world clinical practice remain unknown. Updated performance of the Micra VR leadless pacemaker through five years from the worldwide post-approval registry (PAR) was assessed. All Micra PAR patients undergoing implant attempts were included. Endpoints included system- or procedure-related major complications and system revision rate for any cause through 60 months post-implant. Rates were compared through 36 months post-implant to a reference dataset of 2667 transvenous pacemaker patients using Fine-Gray competing risk models. 1809 patients were enrolled between July 2015 and March 2018 and underwent implant attempts from 179 centres in 23 countries with a median follow-up period of 51.1 months (IQR: 21.6-64.2). The major complication rate at 60 months was 4.5% [95% confidence interval (CI): 3.6%-5.5%] and was 4.1% at 36 months, which was significantly lower than the 8.5% rate observed for transvenous systems (HR: .47, 95% CI: .36-.61; P < .001). The all-cause system revision rate at 60 months was 4.9% (95% CI: 3.9%-6.1%). System revisions among Micra patients were mostly for device upgrades (41.2%) or elevated thresholds (30.6%). There were no Micra removals due to infection noted over the duration of follow-up. At 36 months, the system revision rate was significantly lower with Micra vs. transvenous systems (3.2% vs. 6.6%, P < .001). Long-term outcomes with the Micra leadless pacemaker continue to demonstrate low rates of major complications and system revisions and an extremely low incidence of infection.

Multilevel Venous Obstruction in Patients with Cardiac Implantable Electronic Devices.

Background and Objectives: The nature of multilevel lead-related venous stenosis/occlusion (MLVSO) and its influence on transvenous lead extraction (TLE) as well as long-term survival remains poorly understood. Materials and Methods: A total of 3002 venograms obtained before a TLE were analyzed to identify the risk factors for MLVSO, as well as the procedure effectiveness and long-term survival. Results: An older patient age at the first system implantation (OR = 1.015; p < 0.001), the number of leads in the heart (OR = 1.556; p < 0.001), the placement of the coronary sinus (CS) lead (OR = 1.270; p = 0.027), leads on both sides of the chest (OR = 7.203; p < 0.001), and a previous device upgrade or downgrade with lead abandonment (OR = 2.298; p < 0.001) were the strongest predictors of MLVSO. Conclusions: The presence of MLVSO predisposes patients with cardiac implantable electronic devices (CIED) to the development of infectious complications. Patients with multiple narrowed veins are likely to undergo longer and more complex procedures with complications, and the rates of clinical and procedural success are lower in this group. Long-term survival after a TLE is similar in patients with MLVSO and those without venous obstruction. MLVSO probably better depicts the severity of global venous obstruction than the degree of vein narrowing at only one point.

Abstract 13072: Safety and Efficacy of Lead Extraction at Time of Device Upgrade

Introduction: Patients with permanent pacemakers may require upgrade to ICD or CRT but there is no consensus on whether unused leads should be abandoned or extracted. Transvenous lead extraction (TLE) adds potential risk and can be complex in cases of complete venous occlusion. The safety and efficacy of TLE as a strategy to upgrade pacemakers has not been systematically explored and the impact of venous occlusion is unknown. Aims: 1) Characterize the success and safety of TLE for the indication of pacemaker upgrade to ICD or CRT 2) Assess the effect of complete venous occlusion on outcomes Methods: A total of 50 patients underwent TLE for the sole indication of pacemaker upgrade at UCSD from January 2018 to January 2023. All patients completed preoperative cardiac TLE CT. In-hospital outcomes and procedural variables were collected by chart review. Association with venous occlusion was analyzed using McNemar and t-tests. Results: All 50/50 (100%) patients had successful TLE and successful device upgrade with CRT-D in 44/50 (88%) patients and DC-ICD in 6/50 (12%) patients. No complications occurred (conversion to open extraction, injury, tamponade). Preoperative CT showed complete venous occlusion in 14/50 (28.0%) patients. Median lead extraction fluoroscopy time was 6.0 minutes (IQR: 3.7-8.5). Laser extraction was required in 48/50 patients (96%), laser sheath upsizing in 4/50 (8.0%), conversion to mechanical sheath in 7/50 (14.0%), and telescoping sheaths in 1/50 (2.0%). Venous occlusion was not associated with different baseline characteristics, TLE techniques, or fluoroscopy time (Table 1). Conclusions: TLE in combination with pacemaker upgrade had excellent procedural success. Preoperative CT identified complete venous occlusion in 28% of patients, but this was not associated with technical difficulty, procedural success, or clinical outcomes. Further studies are required to assess the long-term impact of this lead management strategy.

Abstract 12244: Gender Differences in Leadless Pacemaker Peri-Procedural Adverse Events, Long-Term Device Functions, and Clinical Outcomes

Introduction: Some studies suggested gender differences in procedural complication rates and long-term outcomes for trans-venous pacemakers. Little is known about gender differences associated with leadless pacemaker (LP) implantation. Methods: We reviewed all Medtronic Micra LP implants at our institution from 9/2014 to 9/2022. Device parameters (R wave sensing, impedance, and capture threshold), right ventricular pacing burden (RVP), left ventricular ejection fraction (LVEF), and 30-day adverse events post implant were obtained. Results: Among 489 patients, 50.9% were men. Mean follow-up was 1.7 ± 1.5 years. Women were older than men at the time of LP implant (78.1 ± 14.7 vs 75.5 ± 15.3 years old, p=0.04). There were no significant differences in R wave sensing and RVP between genders. Impedance and LVEF were higher in women and capture thresholds were higher in men at both baseline and last follow up. Despite significant differences in device parameters between genders, differences were small and not clinically relevant in most cases (Figure). Mean number of device deployments required at implant was similar: women 1.3 ± 0.6 vs men 1.4 ± 0.9, p=0.16). Implant related complications were similar between women and men: access site hematoma (5 vs 9, p=0.42), pseudoaneurysm (0 vs 2, p=0.49), cardiac perforation (2 vs 1, p=0.62), 30-day re-hospitalization (16 vs 25, p=0.19) and 30-day mortality (16 vs 17, p=0.99). LVEF decreased over time in both genders (Figure). During follow-up, 4 women and 6 men required transvenous cardiac resynchronization therapy (CRT) implantation (p=0.75) and 4 women vs 2 men required transvenous dual chamber pacemaker implantation (p=0.44). Conclusion: Outcomes of leadless pacemaker implantation are similar between women and men. Long-term device function is excellent in both genders. However, about 3% of all patients required device upgrade, highlighting the need for close electrophysiology follow-up after LP implant in both genders.

Chlorhexidine gluconate pocket lavage to prevent cardiac implantable electronic device infection in high-risk procedures

Infection is the most dreaded complication of cardiac implantable electronic devices (CIEDs), particularly in patients undergoing high-risk procedures (eg, generator change, device upgrade, lead/pocket revision). The purpose of this study was to describe the impact of chlorhexidine gluconate (CHG) pocket lavage in high-risk procedures. Patients from a prospective multicenter registry undergoing high-risk procedures were included. CHG lavage was performed by irrigating the generator pocket with 20 cc of 2% CHG without alcohol followed by and normal saline (NS) irrigation. Only NS irrigation was performed in the comparison group. The primary efficacy outcome was CIED-related infection at 12 months. The primary safety outcome was any CHG-associated adverse event. The secondary outcome was CIED infection during long-term follow-up. Propensity score matching (PSM) analysis was performed for the primary efficacy outcome. A total of 1504 patients were included. At 12-month follow-up, the primary efficacy outcome occurred in 4 of 904 CHG (0.4%) and 14 of 600 NS (2.3%) subjects (log-rank P = .005). On multivariate analysis, the use of CHG irrigation was associated with a lower risk of infection at 1-year follow-up (Cox proportional hazard ratio [HR] 0.138; 95% confidence interval [CI] 0.04-0.45; P= .001). This effect persisted during long-term follow-up. PSM demonstrated a significant reduction in CIED-related infection for the CHG group (0.2% vs 2.5%; Cox proportional HR 0.08; 95% CI 0.01-0.59; P = .014). No adverse events were associated with the use of CHG. CHG lavage during high-risk procedures was associated with a reduction in CIED-related infections without any adverse events reported. The benefits of CHG lavage were observed even during long-term follow up and in PSM analysis.

Transvenous Lead Extraction during Cardiac Implantable Device Upgrade: Results from the Multicenter Swiss Lead Extraction Registry.

Device patients may require upgrade interventions from simpler to more complex cardiac implantable electronic devices. Prior to upgrading interventions, clinicians need to balance the risks and benefits of transvenous lead extraction (TLE), additional lead implantation or lead abandonment. However, evidence on procedural outcomes of TLE at the time of device upgrade is scarce. This is a post hoc analysis of the investigator-initiated multicenter Swiss TLE registry. The objectives were to assess patient and procedural factors influencing TLE outcomes at the time of device upgrades. 941 patients were included, whereof 83 (8.8%) had TLE due to a device upgrade. Rotational mechanical sheaths were more often used in upgraded patients (59% vs. 42.7%, p = 0.015) and total median procedure time was longer in these patients (160 min vs. 105 min, p < 0.001). Clinical success rates of upgraded patients compared to those who received TLE due to other reasons were not different (97.6% vs. 93.0%, p = 0.569). Moreover, multivariable analysis showed that upgrade procedures were not associated with a greater risk for complications (HR 0.48, 95% confidence interval 0.14-1.57, p = 0.224; intraprocedural complication rate of upgraded patients 7.2% vs. 5.5%). Intraprocedural complications of upgraded patients were mostly associated with the implantation and not the extraction procedure (67% vs. 33% of complications). TLE during device upgrade is effective and does not attribute a disproportionate risk to the upgrade procedure.

Management of temporary mechanical circulatory support devices in cath-lab and cardiac intensive care unit.

Different temporary mechanical circulatory support (tMCS) devices are available and can be used to maintain end-organ perfusion while reducing cardiac work and myocardial oxygen demand. tMCS can provide support to the right ventricle, left ventricle, or both, and its use can be considered in emergency situations such as cardiogenic shock or in elective procedures such as high-risk percutaneous coronary intervention to prevent haemodynamic deterioration. Invasive and, most importantly, non-invasive haemodynamic parameters should be taken into account when choosing the type of tMCS device and its initiation and weaning timing, determining the need for a device upgrade, and screening for complications. In this context, ultrasound tools, specifically echocardiography, can provide important data. This review aims to provide a description of the different tMCS devices, the invasive and non-invasive tools and parameters to guide their management, and their advantages and drawbacks.

PO-02-079 SAFETY AND FEASIBILITY OF DEVICE EXTRACTION OF THE HIS 3830 SELECTSECURE© LEAD

The 3830 SelectSecure© Lead (Medtronic, MN) is widely used for conduction system pacing. Data regarding the safety and complexity of lead extraction from the septum with this lumenless 4.1 Fr ETFE coated lead is limited to a few reports. To evaluate safety, efficacy, and complexity of 3830 lead extractions implanted on the interventricular septum. Consecutive patients undergoing SelectSecure© lead extractions between Jan 2015 and Jan 2021 at Virginia Commonwealth University were analyzed. Procedural tools, lead dwell times, complications, and indications for lead failure were tabulated. A total of 23 patients had lead extractions during the study period. All leads were implanted in the His bundle region with median dwell time of 190 days (IQR 34-319 days) and mean dwell time of 290 days. Devices were implanted for sick sinus syndrome (13, 57%), AV block (9, 39%), and planned CRT (1, 4%) The most common indication for extraction was lead failure (75%) followed by device upgrade (17%), infection (4%), or a combination of need for upgrade with lead failure (4%). The mean capture threshold prior to extraction was 2.8V±1.9V @ 1 ms. 21 (91%) of patients had successful explant with manual traction alone, 2 (4%) leads required laser sheath, and 1 (4%) patient required both laser and mechanical tools. The only complication was a femoral vein hematoma; total lead extraction with no remnants, was achieved in all patients. Procedural success was complete and safety outcomes were excellent with the caveat that the cohort primarily fell into the low to intermediate risk category, as calculated by the SAFeTY TLE score. The dwell times are relatively short given the more recent advent of the technique. Device extraction of the entirety of the 3830 lead can be done safely despite its placement in the septum and a unique lumenless design. However, most extractions took place after relatively short implant times and more information is needed about extraction of 3830 after long implant times.

CI-452769-2 PERFORMANCE OF LEADLESS PACEMAKERS IN EXTENDED FOLLOW-UP: 5 YEAR RESULTS FROM THE MICRA VR TRANSCATHETER PACING SYSTEM POST-APPROVAL REGISTRY

Prior reports have demonstrated a favorable safety and efficacy profile of the Micra leadless pacemaker over mid-term follow-up; however, long-term outcomes in real-world clinical practice remain unknown. We report 5-year outcomes of the Micra VR leadless pacemaker from the worldwide post-approval registry (PAR). All Micra VR PAR patients (n=1809) undergoing implant attempt were included. Endpoints included system- or procedure-related major complications and system revision rate for any cause through 60 months post-implant. Rates were compared through 36 months post-implant to a reference dataset of 2667 patients implanted with a transvenous pacemaker using Fine-Gray competing risk models. Patients were followed for a median of 48.9 (IQR: 21.6-59.8) months with active patients followed for a median of 59.7 (IQR: 54.2-64.9) months. Median age was 79 (IQR: 71-84) years at implant and patients had multiple comorbidities, including renal dysfunction (21.5%) and heart failure (15.4%). The major complication rate at 60 months was 4.3% (95% CI: 3.4%-5.4%) and was 4.1% at 36 months, which was significantly lower than the 8.5% rate observed for transvenous systems (HR: 0.47, 95% CI: 0.36-0.61; P<0.001; Figure). The all-cause system revision rate at 60 months was 4.9% (95% CI: 3.9%-6.1%). System revisions among Micra patients were mostly for device upgrades (40.2%) or elevated thresholds (28.0%). The most frequent action was to program the device OOO (78.0%), while 10 devices were successfully explanted 2-1442 days post-implant. No infection requiring Micra removal was noted over the duration of follow-up. At 36 months, the system revision rate was significantly lower with Micra vs. transvenous systems (3.3% vs 6.6%, P<0.001). Extended performance data of the Micra leadless pacemaker remains in-line with previously reported data with a 53% reduction in major complications through 36-months relative to transvenous pacemakers. The rate of system revisions was low through 5 years and importantly, no infections requiring Micra removal were observed. Performance will continue to be evaluated in this ongoing trial.

Review of Threats in IoT Systems: Challenges and Solutions

Abstract: The Internet of Things (IoT) is an emerging technology concept that revolutionizes our way of living, ranging from standard household objects to sophisticated industrial tools. They represent a collection of interconnected devices equipped with software, sensors, and several other tools to interact and share information with gadgets and programs in the network infrastructure through the internet in a bid to enhance their decision-making skills. However, with such significant advancements come several issues that intimidate the IT industry, which has deteriorated due to the lack of capacity of various organizations to identify, evaluate, and monitor essential features to ensure adherence to security policies. The absence of efficient and robust security procedures, inaccurate device upgrades, user unawareness, and system tracking are a few issues IoT faces from a security, privacy, and cybersecurity perspective. Thus, there is a need for comprehensive knowledge of these IoT threats and their solutions to leverage their usage efficiently. Hence, this review paper focuses on exploring the different kinds of IoT risks and their potential solutions, which are necessary for the successful performance of IoT devices.

Core integrated simulations for the Divertor Tokamak Test facility scenarios towards consistent core-pedestal-SOL modelling

Deuterium plasma discharges of the Divertor Tokamak Test facility (DTT) in different operational scenarios have been predicted by a comprehensive first-principle based integrated modelling activity using state-of-art quasi-linear transport models. The results of this work refer to the updated DTT configuration, which includes a device size optimisation (enlargement to m and a = 0.70 m) and upgrades in the heating systems. The focus of this paper is on the core modelling, but special attention was paid to the consistency with the scrape-off layer parameters required to achieve divertor plasma detachment. The compatibility of these physics-based predicted scenarios with the electromagnetic coil system capabilities was then verified. In addition, first estimates of DTT sawteeth and of DTT edge localised modes were achieved.

Efficacy and Safety of Transvenous Lead Extraction at the Time of Upgrade from Pacemakers to Cardioverter-Defibrillators and Cardiac Resynchronization Therapy.

Upgrading from pacemakers to ICDs and CRTs is a difficult procedure, and often, transvenous lead extraction (TLE) is necessary for venous access. TLE is considered riskier in patients with multiple diseases. We aimed to assess the complexity, risk, and outcome of TLE among CRT and ICD candidates. We analyzed clinical data from 2408 patients undergoing TLE between 2006 and 2021. There were 138 patients upgraded to CRT-D, 33 patients upgraded to CRT-P and 89 individuals upgraded to ICD versus 2148 patients undergoing TLE for other non-infectious indications. The need for an upgrade was the leading indication for TLE in only 36-66% of patients. In 42.0-57.6% of patients, the upgrade procedure could be successfully done only after reestablishing access to the occluded vein. All leads were extracted in 68.1-76.4% of patients, functional leads were retained in 20.2-31.9%, non-functional leads were left in place in 0.0-1.1%, and non-functional superfluous leads were extracted in 3.6-8.4%. The long-term survival rate of patients in the CRT-upgrade group was lower (63.8%) than in the non-upgrade group (75.2%). Upgrading a patient from an existing pacemaker to an ICD/CRT is feasible in 100% of cases, provided that TLE is performed for venous access. Major complications of TLE at the time of device upgrade are rare and, if present do not result in death.

Upgrading right ventricular pacemakers to biventricular pacing or conduction system pacing: a systematic review and meta-analysis.

Guidelines recommend patients undergoing a first pacemaker implant who have even mild left ventricular (LV) impairment should receive biventricular or conduction system pacing (CSP). There is no corresponding recommendation for patients who already have a pacemaker. We conducted a meta-analysis of randomized controlled trials (RCTs) and observational studies assessing device upgrades. The primary outcome was the echocardiographic change in LV ejection fraction (LVEF). Six RCTs (randomizing 161 patients) and 47 observational studies (2644 patients) assessing the efficacy of upgrade to biventricular pacing were eligible for analysis. Eight observational studies recruiting 217 patients of CSP upgrade were also eligible. Fourteen additional studies contributed data on complications (25 412 patients). Randomized controlled trials of biventricular pacing upgrade showed LVEF improvement of +8.4% from 35.5% and observational studies: +8.4% from 25.7%. Observational studies of left bundle branch area pacing upgrade showed +11.1% improvement from 39.0% and observational studies of His bundle pacing upgrade showed +12.7% improvement from 36.0%. New York Heart Association class decreased by -0.4, -0.8, -1.0, and -1.2, respectively. Randomized controlled trials of biventricular upgrade found improvement in Minnesota Heart Failure Score (-6.9 points) and peak oxygen uptake (+1.1 mL/kg/min). This was also seen in observational studies of biventricular upgrades (-19.67 points and +2.63 mL/kg/min, respectively). In studies of the biventricular upgrade, complication rates averaged 2% for pneumothorax, 1.4% for tamponade, and 3.7% for infection over 24 months of mean follow-up. Lead-related complications occurred in 3.3% of biventricular upgrades and 1.8% of CSP upgrades. Randomized controlled trials show significant physiological and symptomatic benefits of upgrading pacemakers to biventricular pacing. Observational studies show similar effects between biventricular pacing upgrade and CSP upgrade.