Leadless Pacemaker Research Articles

Trends in safety of catheter-based electrophysiology procedures in the last 2 decades: A meta-analysis

BackgroundRapid technologic development and expansion of procedural expertise have led to widespread proliferation of catheter-based electrophysiology procedures. It is unclear whether these advances come at cost to patient safety. ObjectiveThis meta-analysis aimed to assess complication rates after modern electrophysiology procedures during the lifetime of the procedures. MethodsA comprehensive search was performed to identify relevant data published before May 30, 2023. Studies were included if they met the following inclusion criteria: prospective trials or registries, including comprehensive complications data; and patients undergoing atrial fibrillation ablation, ventricular tachyarrhythmia ablation, leadless cardiac pacemaker implantation, and percutaneous left atrial appendage occlusion. Pooled incidences of procedure-related complications were individually assessed by random effects models to account for heterogeneity. Temporal trends in complications were investigated by clustering trials by publication year (2000–2018 vs 2019–2023). ResultsA total of 174 studies (43,914 patients) met criteria for analysis: 126 studies of atrial fibrillation ablation (n = 24,057), 25 studies of ventricular tachyarrhythmia ablation (n = 1781), 21 studies of leadless cardiac pacemaker (n = 8896), and 18 studies of left atrial appendage occlusion (n = 9180). The pooled incidences of serious procedure-related complications (3.49% [2000–2018] vs 3.05% [2019–2023]; P < .001), procedure-related stroke (0.46% vs 0.28%; P = .002), pericardial effusion requiring intervention (1.02% vs 0.83%; P = .037), and procedure-related death (0.15% vs 0.06%; P = .003) significantly decreased over time. However, there was no significant difference in the incidence of vascular complications over time (1.86% vs 1.88%; P = .888). ConclusionDespite an increase in cardiac electrophysiology procedures, procedural safety has improved over time.

TIMES, ARE THEY A–CHANGING? IMPLANTATION AND FOLLOW–UP EXPERIENCE WITH LEADLESS PACEMAKERS (MICRA) AT PISA UNIVERSITY HOSPITAL

Abstract Background Leadless pacing represents a pivotal advancement in cardiac stimulation. Eliminating traditional pacing leads, leadless devices offer reduced complications, a bailout strategy for many previously challenging cases and streamlined procedures. Purpose This retrospective study aimed to compare, starting from December 1st 2023, newer implants (within the 3 years preceding Dec 1st 2023) and older implants (&amp;gt;3 years before) in a single–center experience with M–TPS (Micra Transcatheter Pacing System) in terms of safety and efficacy, at baseline and in a short–term follow–up (6 months). Methods A comprehensive analysis was conducted on 195 patients who underwent leadless pacemaker implantation at our Center, and that were followed–up for a minimum of 6 months. The cohort was stratified into two groups: recent (n=73) and less recent implants (n=122). Procedural variables, patient demographics, and clinical outcomes were documented. Post–implantation follow–up data include pacing threshold, fluoroscopy time, and other relevant variables. Results Comparison between the two groups revealed significant differences fluoroscopy time. Newer implants demonstrated a reduced fluoroscopy time [8 (IQR 5–12) vs 10 minutes (IQR 7–14)], suggesting potential advancements in technique. No significant differences were observed in other procedural or electrical parameters. Discussion: The comparison between older and newer leadless pacemaker implants reveals reassuring constancy in most parameters, suggesting the reliability of the M–TPS. The reduced fluoroscopy time aligns with the evolving proficiency of implanters and improved procedural efficiency. The dependable consistency observed across various parameters strengthens the confidence in the M–TPS, reinforcing its status as a reliable and effective solution for pacing. Conclusion The implantation and follow–up experience at our center elucidates very few differences between newer and older implants. This nuanced analysis contributes to the ongoing evolution of leadless pacemaker technology, which heralds a transformative era in cardiac care. With several years of implementation, accumulated follow–up data unveils valuable insights into its sustained effectiveness, guiding clinicians in optimizing patient outcomes and solidifying leadless pacing as a breakthrough in the realm of cardiac rhythm management.

DON’T FORGET ABOUT CARDIAC AMYLOIDOSIS: WHEN RED FLAGS MATTER

Abstract Case Report A 78–year–old man came to our attention for worsening dyspnea, asthenia and frequent lipothymic episodes in the last few weeks. Nothing remarkable was reported in anamnesis except for periodic cardiological check–ups ascribed to hypertensive heart disease and moderate aortic stenosis. Other cardiovascular risk factors were obesity, previous smoking habits and dyslipidemia. A recent 24–hours ECG monitoring revealed slow permanent atrial fibrillation (AF) with 3–seconds pauses, frequent premature ventricular complexes (PVCs) and some PVCs couplets. On arrival, NT–proBNP was elevated (2952 pg/mL), while ECG showed AF with a heart rate of 50/m and low voltages in peripheral leads. Transthoracic echocardiogram revealed a biatrial dilatation, a severe left ventricular (LV) concentric hypertrophy with a preserved LV ejection fraction (EF) and a moderate aortic stenosis. In addition, a restrictive LV filling pattern, a decreased longitudinal myocardial contraction and an apical sparing of longitudinal strain were reported. Invasive coronary angiography was performed with evidence of normal coronary arteries. Given the echocardiographic suspicion of amyloidosis, a 99mTc–Hydroxymethylene diphosphonate (HMDP) scintigraphy was performed, showing a moderate cardiac uptake and an attenuated bone uptake (Perugini Score 2). Serum and urine immunofixation resulted negative. Genetic testing did not find any mutations in Transthyretin (TTR) gene. Therefore, the diagnosis of TTR wild–type amyloidosis was made. Before discharge, putting it all together, we opted to implant a leadless pacemaker in order to protect the patient from life–threatening bradyarrhythmias. Discussion Although it is currently considered rare, there is growing evidence that cardiac amyloidosis may be more common than once thought. First of all, it should be investigated in HFpEF–patients (heart failure with preserved EF) with LV hypertrophy. Despite several red flags (low QRS voltages, conduction disorders, elevated NT–proBNP, severe LV hypertrophy and aortic stenosis) and various medical consultations, our patient had to wait 4 years or more to be diagnosed with cardiac amyloidosis. Inevitably, a diagnostic delay means loss of time in treatment initiation. Earlier diagnosis would enable us to improve our patients’ survival and heart failure hospitalization. Awareness alone is not enough, we must be right on target too.

POST-HOC STRATIFICATION OF THE RISK OF INFECTION IN EXTRACTED PATIENTS

Abstract Introduction Infection represents one of the most widespread and feared complications of CIED implantation procedures. Most of the time this could even evolve into endocarditis on electrocatheters or septic shock, to the point that the only life-saving therapy becomes the transvenous extraction of electrocatheters. For this reason, the problem often arises of preventing these infectious conditions by carrying out an infectious risk assessment before the implant so as not to incur these complications over time. This study aims to stratify post-hoc the infectious risk of patients extracted in our center to validate the introduction and use of scores for the pre-implantation assessment of infectious risk. Methodology We evaluated 163 patients who underwent transvenous extraction of leads, of which 130 due to pocket infection/endocarditis on leads or sepsis. In these patients, a post-hoc assessment of the risk of infection was made according to the UPCM score, a score created by the University of Pittsburgh. A score value greater than or equal to 7 identifies patients who are more likely to develop an infection over time. This score takes into account risk factors such as: early reoperation, type of device implanted (CRTD vs ICD/PM), presence of more than 2 catheters in place, replacement or revision of the device, use of temporary pacing, intake of corticosteroids or anticoagulants oral, renal function, fever within 24 hours before implantation, presence of diabetes or heart failure, male gender. We then paid particular attention to patients who had undergone an upgrade procedure or to those who had undergone an extraction procedure twice. Results Of the 130 patients in our center who underwent extraction for infection, 112 had a score greater than or equal to 7; On the other hand, 18 were those with a score lower than 7. The average value was found to be 22.9. Conclusions The identification of a score that can be evaluated before the CIED implantation procedure can be an excellent aid in identifying fragile patients who could suffer from infection in the long or short term. By doing this, further alternatives to the transvenous implant could be evaluated, such as the implantation of a leadless pacemaker or subcutaneous ICD in non-PM dependent patients eligible for this.

Harnessing cardiac power: Heart kinetic motion analysis for energy harvesters

Accurately estimating the complex motion of the heart can unlock enormous potential for kinetic energy harvesting. This paper presents a foundational dataset for heart kinetic motion through in-vivo tests and investigates the most influential factors in heart kinetic motion. In-vivo tests on a living pig's heart, with signal processing, were carried out to study the heart movement by heart beating and respiration motions. A network of nine points on the heart was employed for in vivo measurements. These measurements illustrated the kinetic energy signals in displacement, velocity, and acceleration. The results indicated that the motion level varies in distinct locations over epicardium. The statistical features and autocorrelations were reported for these points, illustrating the highest displacement and acceleration. Each heartbeat generated an energy of 14.35 mJ and a power of 1.03 W. However, this available energy is not uniformly distributed. The results illustrated that not only is cardiac movement location-dependent, but the speed of cardiac displacement cycles is also location-dependent. The right atrium has the highest cardiac kinetic movement with an amplitude of 16.19 mm displacement and 16.3 m/s2 acceleration. To evaluate the energy harvesting possibility from the heart's motion, a piezoelectric energy harvester was simulated by the finite element method, implying that the energy harvesting level significantly depends on implant location over epicardium. The results of this study open the potential of designing novel energy harvesters based on accurate heart movements and provide a foundation for future investigations of energy harvesting for leadless pacemaker energy systems.

Contemporary trends of leadless pacemaker implantation in the United States.

Leadless pacemakers (LPM) have established themselves as the important therapeutic modality in management of selected patients with symptomatic bradycardia. To determine real-world utilization and in-hospital outcomes of LPM implantation since its approval by the Food and Drug Administration in 2016. For this retrospective cohort study, data were extracted from the National Inpatient Sample database from the years 2016-2020. The outcomes analyzed in our study included implantation trends of LPM over study years, mortality, major complications (defined as pericardial effusion requiring intervention, any vascular complication, or acute kidney injury), length of stay, and cost of hospitalization. Implantation trends of LPM were assessed using linear regression. Using years 2016-2017 as a reference, adjusted outcomes of mortality, major complications, prolonged length of stay (defined as >6 days), and increased hospitalization cost (defined as median cost >34 098$) were analyzed for subsequent years using a multivariable logistic regression model. There was a gradual increased trend of LPM implantation over our study years (3230 devices in years 2016-2017 to 11 815 devices in year 2020, p for trend <.01). The adjusted mortality improved significantly after LPM implantation in subsequent years compared to the reference years 2016-2017 (aOR for the year 2018: 0.61, 95% CI: 0.51-0.73; aOR for the year 2019: 0.49, 95% CI: 0.41-0.59; and aOR for the year 2020: 0.52, 95% CI: 0.44-0.62). No differences in adjusted rates of major complications were demonstrated over the subsequent years. The adjusted cost of hospitalization was higher for the years 2019 (aOR: 1.33, 95% CI: 1.22-1.46) and 2020 (aOR: 1.69, 95% CI: 1.55-1.84). The contemporary US practice has shown significantly increased implantation rates of LPM since its approval with reduced rates of inpatient mortality.

Six-month electrical performance of the first dual-chamber leadless pacemaker

BackgroundThe first dual-chamber leadless pacemaker (DC-LP) system consists of 2 separate atrial and ventricular devices that communicate to maintain synchronous atrioventricular pacing and sensing. The initial safety and efficacy were previously reported. ObjectiveThe purpose of this study was to evaluate the chronic electrical performance of the DC-LP system. MethodsPatients meeting standard dual-chamber pacing indications were enrolled and implanted with the DC-LP system (Aveir DR, Abbott), including right atrial and ventricular helix-fixation LPs (atrial leadless pacemaker [ALP], ventricular leadless pacemaker [VLP]). Pacing capture threshold, sensed amplitude, and pacing impedance were collected using the device programmer at prespecified timepoints from 0–6 months postimplant. ResultsDe novo devices were successfully implanted in 381 patients with complete 6-month data (62% male; age 69 ± 14 years; weight 82 ± 20 kg; 65% sinus nodal dysfunction, 30% atrioventricular block). ALPs were implanted predominantly in the right atrial appendage anterior base and VLPs primarily at the mid-to-apical right ventricular septum. From implant to 1 month, pacing capture thresholds (0.4-ms pulse width) improved in both ALPs (2.4 ± 1.5 V to 0.8 ± 0.8 V; P <.001) and VLPs (0.8 ± 0.6 V to 0.6 ± 0.4 V; P <.001). Sensed amplitudes improved in both ALPs (1.8 ± 1.3 mV to 3.4 ± 1.9 mV; P <.001) and VLPs (8.8 ± 4.0 mV to 11.7 ± 4.2 mV; P <.001). Impedances were stable in ALPs (334 ± 68 Ω to 329 ± 52 Ω; P = .17) and reduced in VLPs (789 ± 351 Ω to 646 ± 190 Ω; P <.001). Electrical measurements remained relatively stable from 1–6 months postimplant. No differences in electrical metrics were observed among ALP or VLP implant locations. ConclusionThis first in-human evaluation of the new dual-chamber leadless pacemaker system demonstrated reliable electrical performance throughout the initial 6-month evaluation period.

Helix-fixed leadless pacemaker implantation through a valve-in-valve tricuspid prosthesis via the femoral approach.

Leadless pacemakers offer the opportunity to avoid transvenous hardware among patients with tricuspid valve prostheses. We present the first case of a helix-based fixation leadless pacemaker implanted through valve-in-valve tricuspid prostheses in a 43-year-old female with extensive prior cardiac history. At the time of presentation, epicardial pacing was no longer a viable option in the setting of pacemaker dependence. Placement of a helix-fixed, leadless right ventricular pacemaker was performed as a bridge to dual-chamber leadless pacing. This was safely and effectively performed and highlighted favorable procedural characteristics that included RV cavity dimensions and prosthesis type.

Transfemoral leadless pacemaker implantation after interventional or surgical tricuspid valve repair.

Transfemoral leadless pacemaker implantation after interventional or surgical tricuspid valve repair.

Impact of omitting the intravenous heparin bolus on outcomes of leadless pacemaker implantation.

Early guidance recommended a bolus of intravenous heparin at the beginning of leadless pacemaker (LP) implantation procedures. However, due to concern about bleeding complications, more recent practice has tended toward omitting the bolus and only running a continuous heparin infusion through the introducer sheath. The impact of omitting the heparin bolus on procedural outcomes is not clear. We reviewed all Medtronic Micra LP implants at our institution from 9/2014 to 9/2022. The decision to bolus with heparin was at operator discretion. Among 621 LP implants, 326 received an intravenous heparin bolus, 243 did not, and 52 patients were excluded because heparin bolus status could not be confirmed. There was a trend toward more frequent omission of the heparin bolus with more recent implants. Median follow-up after LP implant was 14.3 (interquartile range [IQR]: 8.4-27.9) months. There was no difference between heparin bolus and no bolus groups in the number of device deployments/recaptures (1.42 ± 0.81 vs. 1.31 ± 0.66, p = .15). Implant-related adverse events were also similar between heparin bolus and no bolus groups: access-site hematoma requiring intervention (7 vs. 5, p = .99), pseudoaneurysm (1 vs. 1, p = .99), cardiac perforation (1 vs. 1, p = .99), intraprocedural device thrombus formation (2 vs. 4, p = .41), 30-day rehospitalization (21 vs. 15, p = .98), and 30-day all-cause mortality (16 vs. 14, p = .70). There was one additional nonfatal cardiac perforation in a patient who was excluded due to unknown heparin bolus status. Regarding device electrical parameters between heparin bolus and no bolus groups, there were no significant differences at the time of implant: pacing capture threshold 0.5 ± 0.4 vs. 0.5 ± 0.3, p = .10; pacing impedance 739.9 ± 226.4 vs. 719.1 ± 215.4, p = .52; R wave sensing 11.7 ± 5.7 vs. 12.0 ± 5.4, p = .34). Long-term device performance was also similar between groups. Omission of the systemic heparin bolus at the time of LP implantation appears safe in appropriately selected patients. Heparin bolus may still be considered in long cases requiring multiple device deployments or in patients at high risk for thrombotic complications.

A Direct-Digital 40 μA 100 kb/s Intracardiac Communication Receiver with 250 μs Startup Time for Low Duty-Cycle Leadless Pacemaker Synchronization.

The first commercial dual-chamber leadless pacemaker (LLPM) was introduced recently. The system combines two separate implants situated in the right atrium and the right ventricle of the heart. Implant synchronization is accomplished with conductive intracardiac communication (CIC) using the myocardium and blood as transmission channel. Successful implant synchronization of this dual-chamber LLPM has been demonstrated. However, the continuously active synchronization transceivers, consuming about 800 nA, cause a 25-45% reduction in the projected device longevity. This work proposes an alternative strategy for power-optimized LLPM synchronization, which is based on synchronous duty-cycling of the transceivers and direct-digital CIC (DD-CIC). In line with this strategy, a novel low-power DD-CIC receiver for short-packet communication based on Manchester-encoded data and with fast startup time is presented. The circuit was fabricated in 180 nm CMOS technology and analyzed with respect to sensitivity, current consumption and startup time under highly duty-cycled operation. The receiver achieves a sensitivity of 81.6±7.4 μV at a data rate of 100 kb/s, with an active current consumption of 39.1±0.6 μA and a startup time below 250 μs. Operating the receiver as specified by the proposed LLPM synchronization strategy reduces the current consumption to a measured average value of 73 nA. In conclusion, this work suggests synchronous duty-cycling for CIC-based implant synchronization as a promising concept to severely reduce the current consumption of contemporary dual-chamber LLPMs. Consequently, device longevity may be increased significantly, potentially reducing the frequency of costly and complication-prone re-interventions.

Aveir VR leadless pacemaker: interview with professor Tom Wong

Aveir VR leadless pacemaker: interview with professor Tom Wong

Association of chronic kidney disease and end-stage renal disease with procedural complications and inpatient outcomes of leadless pacemaker implantations across the United States

Leadless pacemakers have emerged as a promising alternative to transvenous pacemakers in patients with kidney disease. However, studies investigating leadless pacemaker outcomes and complications based on kidney dysfunction are limited. The objective of this study was to evaluate the association of chronic kidney disease (CKD) and end-stage renal disease (ESRD) with inpatient complications and outcomes of leadless pacemaker implantations. National Inpatient Sample and International Classification of Diseases, Tenth Revision codes were used to identify patients with CKD and ESRD who underwent leadless pacemaker implantations in the United States from 2016 to 2020. Study end points assessed included inpatient complications, outcomes, and resource utilization of leadless pacemaker implantations. A total of 29,005 leadless pacemaker placements were identified. Patients with CKD (n = 5245 [18.1%]) and ESRD (n=3790 [13.1%]) were younger than patients without CKD and had higher prevalence of important comorbidities. In crude analysis, ESRD was associated with higher prevalence of major complications, peripheral vascular complications, and inpatient mortality. After multivariable adjustment, CKD and ESRD were associated with inpatient mortality (CKD: adjusted odds ratio [aOR], 1.62 [95% CI, 1.40-1.86]; ESRD: aOR, 1.38 [95% CI, 1.18-1.63]) and prolonged length of stay (CKD: aOR, 1.55 [95%CI, 1.46-1.66]; ESRD: aOR, 1.81 [95% CI 1.67-1.96]). ESRD was also associated with higher hospitalization costs (aOR, 1.63; 95% CI, 1.50-1.77) and major complications (aOR, 1.33; 95% CI, 1.13-1.57) after leadless pacemaker implantation. Approximately one-third of patients undergoing leadless pacemaker implantation had CKD or ESRD. CKD and ESRD were associated with greater length and cost of stay and inpatient mortality.

Leadless pacemaker implantation following tricuspid interventions: multicenter collaboration of feasibility and safety.

Permanent pacing is often required following valve intervention (either surgical or percutaneous); however, tricuspid interventions pose specific challenges to conventional pacing. Therefore, leadless pacemaker (LP) implantation may be the preferred strategy when permanent pacing is required after tricuspid valve intervention. To report periprocedural outcomes and follow-up of patients undergoing implantation of a LP system following tricuspid valve interventions. Patients with previous tricuspid valve intervention at the time of attempted implantation of a LP (MicraTM, Medtronic, Minneapolis, MN, USA) were included. Between 2019 and 2022, 40 patients underwent LP implantations following tricuspid interventions in 5 large tertiary centers. The mean age was 68.9 ± 13.7years, and 48% patients were male. The indication for pacing was as following: AVB in 27 (68%) patients, AF with slow ventricular response in 10 (25%) patients, and refractory rapid atrial fibrillation (AF) referred to AV junction ablation in 3 (7%) patients. Most of the patients received Micra VR (78%). The procedure was successful in all patients. The mean procedural time is 58 ± 32min, and the median fluoroscopy time is 7.5min. Electrical parameters were within normal range (threshold: 1.35 ± 1.2V@0.24ms, impedance: 772 ± 245 Ohm, R-wave: 6.9 ± 5.4mV). No acute complications were observed. During a mean follow-up of 10months, electrical parameters remained stable, and 4 deaths were occurred (not related to the procedure). A LP is a safe and efficient option following tricuspid valve interventions.

Biomechanical MEMS Electrostatic Energy Harvester for Pacemaker Application: A Study of Optimal Interface Circuit.

The leadless pacemaker is the most recent pacemaker concept, developed to overcome conventional pacemakers' limitations. This technology offers better comfort to the patients, lower risk from implantation, and higher reliability. However, these devices suffer from limited battery lifetime due to the extreme miniaturization required for implantation inside the heart cavities. This work proposes extending the battery lifetime by converting biomechanical heartbeat energy into electricity using an innovative electrostatic MEMS energy harvesting device. Based on theoretical models and experiments, we propose a general approach to choosing the optimal interface circuit which considers the parasitic capacitance of the circuit, as it is an imperfection that significantly affects the power performance. According to the energy consumed by the last generation commercial leadless pacemakers, the proposed MEMS solution with optimal interface circuit experimentally showed the possibility of extending the pacemaker battery lifetime by up to 44%.

Feasibility of a novel atrial mechanical sensing method for leadless atrioventricular synchronous pacing.

Few studies have demonstrated a high degree of atrioventricular (AV) synchrony with a new leadless pacemaker called Micra AV. Our group previously reported a new and unique sensing method. We believe that this novel sensing method, "Simplified A3 method,"might facilitate better AV synchrony than a conventional sensing method in almost all cases with Micra AV implantation. We conducted a non-randomized retrospective study comparing the two pacing methods at two centers. From December1,2021 to October 31, 2022, Micra AV was implanted for 32 patients at the two centers. Twenty of the 32 patients with sinus rhythm and complete AV block were included in this study. In Group 1, the conventional setting was programmed as follows: auto A3 threshold, auto A3 window-end (WE), and auto A4 threshold turned on during hospitalization. In Group 2, the "Simplified A3 method" was programmed as follows: auto A3 threshold and auto A3WE turned off. Instead, an intentionally prolonged A3WE (850-1000 ms) and low A3 threshold (A3 signal amplitude + 0.5-1.0 m/s2) were programmed. Twenty patients were analyzed. In Group 2, AV synchrony (%AMVp) was significantly higher at the first outpatient clinic (63.0 ± 5.7% vs 81.0 ± 4.2%, p = .03). A3 threshold was significantly lower in Group 2 (5.9 ± 0.7 m/s2, p < .05 vs 2.3 ± 0.5 m/s2, p < .05). Our novel sensing method might be a more feasible sensing method for obtaining higher AV synchrony than the conventional algorithm.

Early real-world implant experience with a helix-fixation ventricular leadless pacemaker.

Roughly one in six patients receiving conventional transvenous pacemaker systems experience significant complications within 1year of implant, mainly due to the transvenous lead and subcutaneous pocket. A new helix-fixation single-chamber ventricular leadless pacemaker (LP) system capable of pre-deployment exploratory electrical mapping is commercially available. Such an LP may mitigate complications while streamlining the implantation. In this study, the initial real-world implant experience of the helix-fixation LP was evaluated following its commercial release. In patients indicated for single-chamber right ventricular pacing, helix-fixation Aveir VR LPs (Abbott, Abbott Park, IL) were implanted using the dedicated loading tool, introducer, and delivery catheter. Implant procedural characteristics, electrical parameters, and any 30-day procedure-related adverse events of consecutive implant attempts were retrospectively evaluated. A total of 167 patients with Class I indication for permanent pacing received implants in four North American centers (57% male, 70years old). Pre-fixation electrical mapping of potential sites allowed repositioning to be avoided in 95.7% of patients. Median [interquartile range] LP procedure and fluoroscopy durations were 25.5min [20.0, 35.0] and 5.7min [4.0, 9.2], respectively. Pacing capture threshold, sensed R-wave amplitude, and impedance were 0.8V [0.5, 1.3], 9.0mV [6.0, 12.0], and 705 Ω [550, 910], respectively. Implantation was successful in 98.8% of patients, with 98.2% free from acute adverse events. The initial, real-world experience of the helix-fixation ventricular leadless pacemaker demonstrated safe and efficient implantation with minimal repositioning, viable electrical metrics, and limited acute complications.

Pacing and Defibrillation Consideration in the Era of Transcatheter Tricuspid Valve Replacement.

Tricuspid regurgitation is a commonly encountered valvular pathology in patients with trans-tricuspid pacing or implantable cardioverter-defibrillator leads. Transcatheter tricuspid valve interventions are increasingly performed in patients at high surgical risk. Implantation of these valves can lead to the "jailing" of a trans-tricuspid lead. This practice carries both short- and long-term risks of lead failure and subsequent infection without the ability to perform traditional transvenous lead extraction. Herein, this manuscript reviews available therapeutic options for lead management in patients undergoing transcatheter tricuspid valve interventions. The decision to jail a lead may be appropriate in certain high-risk cases, though extraction may be a better option in most cases given the variety of options for re-implant, including leadless pacemakers, valve-sparing systems, epicardial leads, leads placed directly through prosthetic valves, and the completely subcutaneous implantable-defibrillator. A growing number of patients meet the requirement for CIED implantation in the United States. A significant proportion of these patients will have tricuspid valve dysfunction, either related to or independent of their transvenous lead. As with any percutaneous intervention that has shown efficacy, the role of TTVI is also likely to increase as this therapy advances beyond the investigational phase. As such, the role of the heart team in the management of these patients will be increasingly critical in the years to come, and in those patients that have pre-existing CIED leads, we advocate for the involvement of an electrophysiologist in the heart team.

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.

Safety and performance of a novel subxiphoidal pacemaker system.

Traditional cardiac pacemakers commonly have a range of complications related to the presence of intracardiac leads. A new class of extravascular and leadless pacemakers has recently emerged with the potential to mitigate these complications and expand access to cardiac pacing. The objective of this study is to evaluate the implantation, short-term chronic safety, and performance of a novel subxiphoidal extracardiac pacemaker. Normal Yorkshire Cross swine (n = 16) were implanted with the subxiphoidal pacemaker. The pacemaker was inserted through a midline chest incision and clipped to the underside of the sternum, with the stimulation electrode placed on the anterior pericardium. Animals were chronically paced and followed for 90days post-implant, with periodic measurement of pacing capture threshold (PCT) and electrode impedance. All 16 animals were successfully implanted with the study device. At implant, a consistent average PCT of 2.2 ± 0.4V at a pulse width of 1.0ms was observed in all animals, with an average implant impedance of 648 ± 44 Ω. Chronic pacing was programmed at a rate of 60bpm, an amplitude of 3.4 ± 0.7V, and a pulse width of 1.0ms. PCT rose to 4.6 ± 0.8V at 14days and stabilized; at 90days, PCT was 3.8 ± 1.2V and electrode impedance was 533 ± 105 Ω. All implanted animals completed the study with no clinically significant findings, no clinically significant abnormalities, and with no adverse events that affected animal welfare. This study demonstrated the safety and feasibility of a novel subxiphoidal extracardiac pacemaker to deliver short-term chronic extravascular therapy. Further studies are required to assess the safety, feasibility, and long-term chronic pacing performance in human subjects.