Leadless Pacing Research Articles

Implantation of leadless pacing systems in patients early after tricuspid valve surgery: A feasible option.

After tricuspid valve (TV) surgery due to tricuspid regurgitation (TR), patients needing a permanent pacemaker often receive an epicardial lead implantation. This may result in delayed recovery from open-chest surgery and increased postoperative risk. Leadless pacemaker (LPM) implantation may represent a valuable option. A total of 14 consecutive patients underwent LPM implantation (Micra Transcatheter Pacing System, Medtronic, Minneapolis, MN) early after TV surgery. The pacing indication in those patients was atrial fibrillation with a slow atrio-ventricular (AV) conduction or atrial fibrillation and a concomitant AV block III. Three patients already had a pacemaker prior to surgery, which was explanted during TV repair. Three patients received a valve replacement with a bioprosthesis, while the remaining eight patients received a TV repair. All procedural data and device measurements during and after LPM implantation were recorded. Transthoracic echocardiography was performed prior and post LPM implantation, showing no changes in TV or bioprosthesis performance. The device measurements were within an adequate range: threshold: 0.83±0.34 V @ 0.24±0ms, impedance: 480 ± 58.88ohm, and R-wave: 10.10±3.60mV. LPM implantation was successful in all patients with a mean procedural time of 32±11.8minutes, fluoroscopy time of 3.71±3.15minutes, and dose-area product of 536.67±811.26 cGy/m2 . Implantation of an LPM early after TV surgery is a feasible option. LPM implantation does not affect TV or bioprosthesis performance in transthoracic echocardiography.

Leadless pacemaker for patients following cardiac valve intervention

Permanent pacing is common after valve intervention. The presence of a conventional pacemaker in this population is recognized as a risk factor for infectious events. Therefore, a leadless pacing system could be the preferred strategy when permanent pacing is required after valve intervention. To report periprocedural outcomes and follow-up of patients undergoing implantation of a leadless pacing system after valve intervention. Patients with previous valve intervention at the time of attempted implantation of a leadless pacemaker (Micra™, Medtronic, Minneapolis, MN, USA) were included, and were compared with a control group (patients also implanted with Micra™ without valve intervention). Among a total of 170 Micra™ implantation procedures, 54 patients (31.8%) had a history of valve intervention: 28 after aortic valve replacement; 10 after mitral valve replacement; one after single tricuspid valvuloplasty; and 15 after multiple valve surgery. Median age of the patients was 82.5 (77.0-86.0) years and 53.7% were male. Patients with previous valve intervention had a higher incidence of arterial hypertension (P=0.014) and ischaemic heart disease (P=0.040). The primary indications for permanent pacing after valve intervention were high-degree atrioventricular block (59.3%) and atrial fibrillation with bradycardia (27.8%). Micra™ was successfully implanted in all patients (n=170) without any procedure-related major complications. During a median follow-up of 12 months, electrical performance was excellent and similar in both groups. Also, a similar reduction in left ventricular ejection fraction was observed at 12 months in both groups, which was correlated with the percentage of right ventricular pacing. A leadless pacemaker is safe and efficient after valve intervention, and therefore represents an effective pacing option in patients after valve intervention.

Leadless pacemaker implantation under direct visualization during valve surgery

ObjectiveThe leadless cardiac pacemaker is typically implanted percutaneously and has been widely used for patients who have already undergone valve surgery. We sought to determine the feasibility and safety of implanting the leadless pacemaker under direct visualization during valve surgery. MethodsWe performed a retrospective analysis of consecutive adult patients (n = 15) who underwent implantation of a leadless pacemaker under direct visualization at the time of valve surgery. Indications for single-chamber pacing were sick sinus syndrome with pauses (53.3%), atrial fibrillation with slow ventricular rates (13.3%) or complete heart block (6.6%), and elevated risk for postoperative heart block (26.6%). Leadless pacemaker performance and pacing percentage were assessed. ResultsPatients' age was 67.5 ± 17 years, 6 patients (40%) were male, and 14 patients (93%) had atrial fibrillation. Isolated tricuspid valve replacement was performed in 5 patients (33.3%), and the remainder underwent multivalve surgery that included concomitant tricuspid valve repair/replacement. In 93% of the patients (n = 14), the immediate post–cardiopulmonary bypass pacing thresholds were normal (≤2.0 V at 0.24 ms) and normalized in the remaining patient by the next morning. The impedance/sensing values were normal and stable through follow-up (151 ± 119 days) in all patients. Reliable leadless pacemaker performance allowed for deferral of temporary epicardial wires in 11 patients (73%). There were no procedural complications or device malfunction. ConclusionsLeadless cardiac pacemaker implantation during valve surgery is feasible and safe. This hybrid approach to pacing may simplify the perioperative management of patients undergoing valve surgery who have an indication for single-chamber pacing.

Tracking the motion of intracardiac structures aids the development of future leadless pacing systems.

Leadless pacemakers preclude the need for permanent leads to pace endocardium. However, it is yet to be determined whether a leadless pacemaker of a similar design to those manufactured for the right ventricle (RV) fits within the left ventricle (LV), without interfering with intracardiac structures. Cardiac computed tomography scans were obtained from 30 patients indicated for cardiac resynchronisation therapy upgrade. The mitral valve annulus, chordae tendineae, papillary musclesand LV endocardial wall were marked in the end-diastolic frame. Intracardiac structures motions were tracked through the cardiac cycle. Two pacemaker designs similar to commercially manufactured leadless systems (Abbott's Nanostim LCP and Medtronic's Micra TPS) as well as theoretical designs with calculated optimal dimensions were evaluated. Pacemakers were virtually placed across the LV endocardial surface and collisions between them and intracardiac structures were detected throughout the cycle. Probability maps of LV intracardiac structures collisions on a 16-segment AHA model indicated possible placement for the Nanostim LCP, Micra TPS, and theoretical designs. Thresholding these maps at a 20% chance of collision revealed only about 36% of the endocardial surface remained collision-free with the deployment of Micra TPS design. The same threshold left no collision-free surface in the case of the Nanostim LCP. To reach at least half of the LV endocardium, the volume of Micra TPS, which is the smaller design, needed to be decreased by 41%. Due to the presence of intracardiac structures, placement of leadless pacemakers with dimensions similar to commercially manufactured RV systems would be limited to apical regions.

Leadless cardiac pacing in resource limited settings: A Groote Schuur hospital experience with the Micra leadless pacemaker

Background: Cardiac pacemakers improve survival and quality of life in patients with atrioventricular (AV) block. However, conventional pacemakers carry a small risk of both acute and chronic lead and pacemaker generator complications. Leadless pacemakers negate these risks by not having a pacing lead and a subcutaneous generator. We report our Groote Schuur Hospital experience with the Medtronic Micra transcatheter pacing system (TPS). Methods: We report a consecutive case series of patients that received the Micra leadless pacemaker. The Micra transcatheter pacemaker, a single chamber ventricular pacemaker, is inserted using a TPS via the femoral vein into the right ventricle. Implantation data were obtained, and medical records were reviewed for the 6 weeks and 1-year follow-up visits. Results: A total of 5 patients were implanted with a Micra leadless pacemaker from 11 March 2015 - 2 November 2016. Four patients were male and 1 female, with an average age of 64 years. Four patients received the pacemaker for a second- or third-degree AV block and 1 patient received the pacemaker for unexplained syncope and right bundle branch block. The Micra leadless pacemaker was successfully implanted in all patients with no acute implantationrelated complications. One-year follow-up was available for 4 patients with good pacing thresholds, sensitivity and impedance. One patient demised after 9 months post Micra implantation due to unrelated causes (acute myeloid leukaemia). Conclusion: The Micra leadless pacing system is safe and effective and shows good short-term results in a real-world, resource-limited setting. This form of pacing offers a viable option for patients who require pacing for AV block, especially in patients with vascular access problems or who are at high risk of lead or pacemaker generator complications.

P1468Four years follow-up of leadless pacing system single center real life experience compared to data of the prospective trial

Abstract Funding Acknowledgements none OnBehalf Cologne Registry Introduction The Micra™ leadless intracardiac pacing system has been introduced and implemented into clinical routine more than three years ago. Feasibility, implantation safety and acute success have been proven in the setting of controlled studies. Additionally few real- life and post-implantation data exist. We aimed to report our single center follow-up (FU) data in comparison with the results of the prospective controlled Micra™- studie. Methods In 112 patients (69 men; age: 79 ± 10 y) successful Micra™ implantation was performed.Pacemaker interrogation was performed one to seven days after implantation and during FU (1; 3; 6, than every 6 month) up to 48 month. Data were assessed in a real-life setting and compared with existing data of the controlled prospectiv trial. Results The implantation was successful in all 112 attempts without procedure or device-related major complications. During Follow up there was one patient developing severe heart failure symptoms resulting in an implantation of a CRT-device and switching of the leadless pacemaker system. The average acute thresholds, sensing and impedance after system release were: 0.63 ± 0.42V@0.24ms; 9,94 ± 3,61mV and 705 ± 166 Ohm. During follow up of up to 4 years neither, pacemaker failure, nor infections were reported. Measurements were reevaluated for long-term thresholds, sensing and impedance: 0.54 ± 0.16V @ 0.24 ms; 16,15 ±4,22 mV and 579 ± 133 Ohm. In the first three years no significant changes from acute to long-term measurements were detectable. In comparison to the data of the controlled trial the measurements of our real-life cohort was very similar. Conclusion In a real life setting the implantation of the leadless Micra™ system demonstrates high rate of implant success without major complications. Also shown were stable long-term system parameters in the clinical setting of up to two years of follow up. These data of every day clinical practice support the findings of the prospectiv trials.

A Battery‐ and Leadless Heart‐Worn Pacemaker Strategy

AbstractOver the past half‐century, cardiac pacing technology has adhered to one basic system. However, many pacemaker‐related complications are related to this system, particularly in terms of the power supply and leads. Here, for the first time a heart‐worn pacemaker strategy is presented, which allows batteryless powering and leadless pacing. The batteryless feature is attained via heart‐extrusion energy scavenging through a micromachined piezoelectric thick film transducer. A record in vivo output current of 30 µA is obtained in an adult swine by the implanted piezoelectric transducer, which can effectively drive a commercial cardiac pacemaker. The exocardial pacing method is demonstrated by this batteryless pacemaker functions without a device or leads placed within the cardiac chambers. Lead‐ or batteryless options are being explored as new basic features of cardiac pacemakers. The presented heart‐worn pacemaker strategy may be useful in future pacing technology.

First transcatheter leadless pacemaker implantation in apediatric patient with agenetic disease.

Apediatric patient suffering from Marden-Walker syndrome, arare genetic disease, was referred to the authors' hospital for syncope due to bradycardia. Since this disease is associated with severe joint contractures, atranscatheter leadless pacing system (TPS) was chosen. Despite the small body size and complex anatomy, TPS implantation was feasible, demonstrating that it is asafe alternative in difficult venous access compared to aconventional pacemaker with increased risk of lead complications in these patients.

Leadless pacing – more and more common but…

The comment presents the results of observational registry study, referring to the current European practice of leadless pacemakers implantation (LP). The results of the work and their limitations were discussed; especially against the background of previous European snapshot data and the characteristics of the use of LP in Poland.

Leadless pacing in cardiac transplant recipients: Primary results of a multicenter case experience

About 4.5–20% of patients after heart transplant require pacemaker (PM) implantation. The high infective risk profile and the low probability of pacing dependency make heart-transplanted patients the ideal candidates for a leadless single-chamber PM. We report the first multicenter experience of leadless PM implantation in a series of heart-transplanted patients with a long-term follow-up. Our data confirm the feasibility and acceptable safety of leadless device in this peculiar kind of patients, despite implantation seems to be slightly more challenging with respect to non-transplanted patients. Although more data are required, a leadless single-chamber surveillance PM seems a valuable option for heart-transplanted patients.

First description of a successful leadless pacemaker implantation via the left internal jugular vein (in a 20 kg patient)

We demonstrate a case series of 8 pediatric patients, all under 30 kg, who had leadless pacemaker implants via the internal jugular vein.A retrospective review of pediatric leadless pacing placement via the internal jugular vein at the University of Minnesota Masonic Children's Hospital and UC Davis Medical Center from 2018 through 2021 was performed. Rationales for pacing, demographics of patients, pacing thresholds, and longevity of devices were recorded.Eight internal jugular pacemaker insertions were performed successfully in patients weighing between 10.9 kg and 29 kg. Five patients had Micra implantation via the right internal jugular vein, whereas 3 patients had insertion via the left internal jugular vein. No surgical cut-downs were performed. No venous complications occurred. Up to 3 years of follow-up were noted.Leadless pacemaker implantation, via left or right internal jugular veins, is feasible without surgical cutdown in patients <30 kg

CONCURRENT IMPLANTATION OF A LEADLESS PACEMAKER FOLLOWED BY TAVR IS A NOVEL AND FEASIBLE PROCEDURE IN PATIENTS WITH SEVERE AORTIC STENOSIS AND SICK SINUS SYNDROME

Transcatheter aortic valve replacement (TAVR) is a minimally invasive treatment strategy for patients with symptomatic aortic stenosis, and is a non-inferior alternative to surgical valve replacement. Leadless right ventricular pacing is an alternative to traditional transvenous pacing with the

Implantable cardioverter defibrillators - the past, present and future.

Since their formal introduction in 1980, implantable cardioverter defibrillators (ICDs) have undergone innumerable design modifications through several generations. They are indispensable today in successfully managing fatal ventricular arrhythmias. Their role in averting sudden cardiac death is recognized beyond doubt. Their applications and indications have continuously expanded over the last two decades. This article reviews the salient features in the evolution of ICDs, their current indications, recent advances and future directions. With more advanced detection algorithms, the potential integration with leadless pacing, and the possibility to serve as a remote monitoring device to recognize atrial fibrillation, acute ischemia, or electrolyte imbalance, the application of ICDs is rapidly evolving.

Selección de lo mejor del año 2019 en estimulación cardiaca

A summary is presented of the highlights in cardiac pacing published in 2019, especially in the field of physiological pacing including His-bundle and left bundle branch pacing. Comments are also made on the published experience in leadless pacing, the latest studies on pacing in vasovagal syncope, subclinical atrial fibrillation detected in electronic devices, as well as new strategies in the prevention of cardiac implantable electronic device infection, including novel aspects of cardiac resynchronisation therapy.

Leadless cardiac pacing in the elderly: less is more

Leadless cardiac pacing in the elderly: less is more

Comparison of Leadless Pacing and Temporary Externalized Pacing Following Cardiac Implanted Device Extraction.

Pacemaker-dependent (PD) patients undergoing implantable cardiac electronic device extraction often must be subjected to temporary pacing interventions. We sought to determine the safety and utility of a leadless pacing system (Micra™; Medtronic, Minneapolis, MN, USA) in patients undergoing system extraction as compared with externalized temporary transvenous right ventricular lead (temp-perm) placement. We performed a retrospective cohort analysis of all patients receiving either permanent Micra™ or temp-perm systems following system extraction from October 2013 to September 2017 at Vanderbilt University Hospital. The Micra™ and temp-perm cohorts included nine and 27 patients meeting the inclusion criteria, respectively. System infection was the most common indication for extraction (67% Micra™, 84% temp-perm), but no patients had active bacteremia at the time of permanent system reimplantation. There was no difference in system type (p = 0.09) or mean lead dwell time extracted (109 versus 81 months; p = 0.93). Procedure times were comparable between the two groups (180 versus 194 minutes; p = 0.74). Patients receiving Micra™ systems had shorter hospital stays after extraction (two versus eight days; p < 0.005), with no difference in major complications (11% versus 15%; p = 0.78) or 30-day (11% versus 7%; p = 0.77) or 90-day (11% versus 11%; p = 0.45) mortality. No reinfections were observed in either group at 90 days. Implantation of the Micra™ pacing system in select PD patients after system extraction is feasible and appears to reduce the hospital length of stay as compared with the use of temp-perm systems.

Rendimiento del marcapasos cardiaco Micra en nonagenarios

Introduction and objectivesThe Micra transcatheter pacing system has shown high effectiveness and a lower complication rate than conventional transvenous pacemakers. However, the benefit of the device is unknown in the very old population (≥ 90 years). The aim of this study was to evaluate the safety and effectiveness of Micra in patients ≥ 90 years. MethodsWe present a prospective observational study with consecutive patients aged >70 years who underwent implantation of a Micra pacemaker system. Patients were divided into 2 groups: ≥ 90 and<90 years. ResultsThe Micra system was implanted in 129 patients, of whom 41 were aged ≥ 90 years and 88<90 years. The device was successfully implanted in 40 (97.6%) patients ≥ 90 years and in 87 (98.9%) patients<90 years (P=.58). An adequate position was achieved with need for ≤ 2 repositions in 97.5% and 91.9% of patients, respectively (P=.32). Procedure time (26.1 ±11.6 vs 30.3 ±14.2minutes; P=.11) and fluoroscopy time (6.4 ±4.7 vs 7.2 ±4.9minutes; P=0.41) were similar in the 2 groups. There were 3 major complications (2.3%), all in the group aged<90 years: 1 cardiac perforation, 1 femoral hematoma, and 1 femoral pseudoaneurysm. Thirteen patients aged ≥ 90 years (31.7%) and 16 patients aged <90 years (18.2%) died during a mean follow-up of 230±233 days and 394±285 days, respectively. There were no device-related deaths. No infection, dislocation or migration of Micra were observed. The electrical performance was optimal at follow-up. ConclusionsThe Micra leadless pacing system seems to be safe and effective in patients older than 90 years. It may be considered a reasonable alternative to conventional transvenous pacing in this population.Full English text available from: www.revespcardiol.org/en

A novel use of leadless pacing in a patient with Parkinson’s disease

This case report records a novel indication for implantation of a leadless Micra transcatheter pacing system (TPS). We present the case of a 66 year-old man suffering from Parkinson’s disease who was admitted to the hospital with a third degree heart block which developed into cardiac arrest. Due to two previously implanted deep brain stimulation devices, which occupied the space where a standard pacemaker impulse generator would be located, placement of a standard pacemaker was deemed inappropriate. The patient was therefore qualified for a leadless Micra TPS implantation. The procedure was uneventful and the patient was discharged after undergoing extensive treatment of an underlying fungal pneumonia.

Patient selection, pacing indications, and subsequent outcomes with de novo leadless single-chamber VVI pacing.

Patient selection is a key component of securing optimal patient outcomes with leadless pacing. We sought to describe and compare patient characteristics and outcomes of Micra patients with and without a primary pacing indication associated with atrial fibrillation (AF) in the Micra IDE trial. The primary outcome (risk of cardiac failure, pacemaker syndrome, or syncope related to the Micra system or procedure) was compared between successfully implanted patients from the Micra IDE trial with a primary pacing indication associated with AF or history of AF (AF group) and those without (non-AF group). Among 720 patients successfully implanted with Micra, 228 (31.7%) were in the non-AF group. Reasons for selecting VVI pacing in non-AF patients included an expectation for infrequent pacing (66.2%) and advanced age (27.2%). More patients in the non-AF group had a condition that precluded the use of a transvenous pacemaker (9.6% vs. 4.7%, P = 0.013). Atrial fibrillation patients programmed to VVI received significantly more ventricular pacing compared to non-AF patients (median 67.8% vs. 12.6%; P < 0.001). The overall occurrence of the composite outcome at 24 months was 1.8% with no difference between the AF and non-AF groups (hazard ratio 1.36, 95% confidence interval 0.45-4.2; P = 0.59). Nearly one-third of patients selected to receive Micra VVI therapy were for indications not associated with AF. Non-AF VVI patients required less frequent pacing compared to patients with AF. Risks associated with VVI therapy were low and did not differ in those with and without AF.

Leadless Pacemakers: Recent and Future Developments.

Leadless pacemakers were developed to reduce complications associated with transvenous pacemaker implant and long-term follow-up. Since initial market release, however, there have been registry and single-center reports documenting improvements in implant technique, reduced complication rates, and new patient populations studied. Most studies have demonstrated a further reduction in complication rates and safe implant in those on continuous anticoagulation. Perforation rates are decreasing but still occur and risk factors include BMI < 20kg/m2, age ≥ 85years, females, history of heart failure, indication not including atrial fibrillation, and chronic lung disease. Device infections are exceedingly rare, even in those undergoing infected transvenous devices at the same time. For appropriate patients, leadless pacing is a safe and reasonable option, especially if atrial-based sensing or pacing is not needed. Future iterations may include VDD pacing, atrial pacing, dual-chamber pacing, biventricular pacing, and device-device communication.