Wireless Communication Between Paired Leadless Pacemakers for Dual-Chamber Synchrony.

Percutaneous solution for a frequent complication after transcatheter aortic valve replacement: A case of atrioventricular leadless pacemaker implantation after transcatheter aortic valve replacement

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

Preclinical safety and electrical performance of novel atrial leadless pacemaker with dual-helix fixation.

The aim of this analysis was to evaluate the upgradeability of a single-chamber leadless pacemaker (LP) to a dual-chamber system in patients indicated for a dual-chamber pacemaker. A prospective, multicentre study evaluated the safety and performance of a dual-chamber LP. The study included patients with a prior ventricular LP to evaluate its upgradeability. Patients had an attempted atrial LP implant, and if successfully implanted, the LPs were paired to a dual-chamber pacing mode to evaluate upgrade success. Patients were followed for 12 months from the attempted atrial LP implantation. Among 35 patients with an attempted upgrade (62.9% male, average age 70 years), the most common primary indication was sinus node dysfunction (57.1%). Out of 35 patients, 91.4% had successful upgrades. The mean atrial device electrical measurements stabilized within 1 month from the procedure and remained stable through 12 months (capture threshold at 0.4 ms 0.8 ± 0.6 V, sense amplitude 4.5 ± 2.7 mV at 12 months). A total of five (14.3%) patients experienced seven complications, all of which were procedure-related. There were no device or procedure-related deaths. The total estimated battery longevity (accounting for time since implant) evaluated at 12 months was 11.3 ± 4.2 and 5.7 ± 2.6 years for the ventricular and atrial LPs, respectively. One patient required an atrial LP revision 10 months after implantation. The LP was retrieved and replaced. These data confirm the feasibility, safety, and long-term effectiveness of adding an atrial LP in patients with a pre-existing ventricular LP to achieve dual-chamber leadless pacing.

Funding AcknowledgementsType of funding sources: Private company. Main funding source(s): Medtronic, inc.IntroductionAdvances in leadless pacemaker technology have enabled accelerometer based atrioventricular synchronous (AVS) pacing by sensing atrial mechanical contraction. However, acute safety performance of these devices in real-world clinical practice has not been assessed.ObjectivesTo report the acute performance of the Micra AV transcatheter pacemaker from the worldwide Micra AV post-approval registry (PAR).MethodsThe Micra AV PAR is an ongoing prospective single-arm observational study designed to assess the safety and effectiveness of the Micra AV system in the real-world setting. Patients enrolled in the Micra AV PAR will be followed for 3 years. For the present interim analysis, baseline characteristics, total AV synchrony index (sum of %AM-VP, %AM-VS, and AV conduction mode switch percentage), and major complications occurring within 30-days of implant were summarized and compared to a historical cohort of 2,667 transvenous dual chamber (TV-DC) pacing patients.ResultsThe device was successfully implanted in 797 of 802 patients (99.4%) at 99 centers. Mean age was 74.1±15.1 years and 42.3% were female. The most common pacing indication was AV block (55.7%). Comorbidities included diabetes (29.7%), CAD (22.8%), and heart failure (12.1%), with 31.3% precluded from transvenous device therapy. Micra AV patients were on average older (74.1 vs. 71.1 yrs, P<0.0001) and had a significantly higher incidence of renal disease (22.3% vs. 9.8%, P<0.0001). Major complications occurred in 2.6% of Micra AV patients and in 7.1% TV-DC patients (P<0.001, Figure). The reduction in major complications was largely driven by the absence of pneumothoraces and lead dislodgements among Micra AV patients. Of the 309 patients programmed to VDD mode with at least 30 days of device follow-up, the median AV synchrony index was 86.0% (IQR: 69.2% - 97.2%). Mean A4 amplitude was 2.1±1.6 m/s2 post-implant and 2.2±1.7 m/s2 at follow-up (P=0.57) in 308 patients with paired assessments.ConclusionsThe Micra AV leadless pacemaker was implanted with a high rate of success in patients with a high co-morbidity burden, with a significantly lower rate of acute complications relative to dual-chamber transvenous pacemakers despite patients being older and having a higher incidence of renal disease. Longer-term performance will continue to be assessed in this ongoing trial.Major Complications Within 30-days

Leadless pacemakers (L-PM) are an emerging effective and safe technology that offer an alternative to conventional pacemakers (C-PM) for right ventricular stimulation. However, there is little information about their potential benefits for quality of life (QoL) in patients with L-PM. We compared QoL between patients with L-PM and C-PM. The study population comprised patients undergoing single chamber pacemaker implantation from December 2016 to March 2018. The SF-36 questionnaire was used to evaluate QoL at baseline and at 6 months of followup. We also used a questionnaire consisted of 10 specific questions related to the implant procedure. A total of 106 patients (64 C-PM; 42 L-PM) were included. There were no differences in baseline characteristics between the groups (C-PM vs L-PM), except for age (81.5 vs 77.3 years; P = .012) and diabetes (38% vs 17%; P = .021). Baseline SF-36 scores did not differ between the groups. At 6 months followup, patients in the L-PM group scored significantly higher on physical function (63 vs 42; P < .001), physical role (64 vs 36; P = .004), and mental health (75 vs 65; P = .017), even after adjusting for covariates. Pacemaker-related discomfort and physical restrictions were significantly lower for the L-PM group. L-PM is associated with better QoL than C-PM in both physical and mental health. Patients undergoing L-PM implantation reported less procedure-related discomfort, physical restriction, and preoccupation.

Background A leadless pacemaker (L-PM) has been designed to avoid the need for a pacemaker pocket and transvenous lead. Long-term safety will largely depend on the need for replacements, mainly due to battery depletion (end-of-life). While the mean L-PM battery longevity predicted by the manufacturer is 12 years, real-world longevity data are still scarce. We aimed to describe L-PM parameters’ stability and battery longevity during the mid-term follow-up. Methods Single-center registry of consecutive patients undergoing L-PM implantation from May 2015 to November 2023. Procedural characteristics, lead parameters and battery longevity were collected immediately after implantation and during the most recent follow-up visit. Results Overall, 261 consecutive patients had a transcatheter L-PM implanted through a femoral vein (mean age 78±10 years; 66% male). Mean procedural duration was 44±28min and fluoroscopy time was 4,4±3,9min. The device was successfully implanted in all but one patient. The main indications for permanent pacing were high-degree atrioventricular block [N=130 (50%)], atrial fibrillation with pauses [N=78 (30%)], and sinus node disease [N=28 (11%)]. Immediately after implantation, three cases (1,2%) of pericardial effusion (one with tamponade) were reported. In one case (0,4%), a conventional pacemaker was implanted due to L-PM acute dysfunction. No other procedure-related complications, including dislodgment, were reported at discharge. After a mean follow-up of 2,8±1,7years, the pacing threshold and R-wave amplitude remained stable [0,67mV vs. 0,62mV (p=0,9); and 10,3mV vs. 16,1mV (p&amp;lt;0,001), respectively] and mean ventricular pacing was 54±38%. Expected battery longevity was &amp;gt;8 years (maximum value) in 84% of the patients. In the subgroup of patients with &amp;gt;5 years of follow-up (N=20; mean follow up of 6,3±1,8years), the expected battery longevity was &amp;gt;8 years in 85% (N=17) of the patients. In three cases, the L-PM was upgraded to cardiac resynchronization therapy or left bundle branch area pacing due to pacing-induced left ventricular dysfunction. There was one case of L-PM end-of-life 6 years after implant (pacing threshold 0,5mV; ventricular pacing 100%), in which a second L-PM was successfully implanted. Overall, 78 (31%) patients died, a mean of 2,2±1,9 years after L-PM implantation, none related to the device. Conclusion In this real-world cohort, L-PM maintained stable pacing parameters and, in the mid-term follow-up, only one battery depletion was observed while expected longevity remained above 8 years in the large majority of patients. Longer follow up will allow better understanding of both technical and clinical aspects relevant to manage end-of-life devices.Table 1Figure 1

Background: Around 10% of patients need a permanent pacemaker due to conduction issues in heart post-valvular interventions. The transvenous pacemaker has many complications compared to novel Leadless pacemaker(LPM) implantation. Objective: The main aim of this review is to compare the outcomes between conventional transvenous pacemakers and leadless pacemaker implantation after valvular intervention. Method: We conducted a comprehensive search of PubMed and ScienceDirect databases for relevant studies published between 2019 and 2024 using the keywords- pacemaker implantation and valvular intervention. Studies available in full text and in English language were included. After removing duplicates using the Rayyan tool, the remaining studies were screened and selected based on predefined inclusion criteria. Eligible studies included retrospective analyses of patients aged over 40 years, with indications for leadless pacemaker implantation such as atrial fibrillation, sick sinus syndrome, complete heart block, or complications following pacemaker implantation. Patients who had previously undergone implantations were excluded. We performed a qualitative synthesis of data to note the comparisons. Result: A total of 9 studies were included, comprising 10,776 patients, of whom 1121 underwent LPM implantation and 9655 received conventional transvenous pacemakers. Indications for LPM following valvular interventions included atrial fibrillation(n=24), complete heart block(n=20), bradycardia(n=26), high-degree atrioventricular (AV) block(n=30), and left bundle branch block(n=9). For conventional transvenous pacemakers, complete heart block(n=24) and high-degree AV block(n=7) were the primary indications. Compared to LPM, patients with conventional pacemakers reported more complications like pocket formation, pericardial effusion, pneumothorax, and infections, along with increased hospital stay duration. A few patients with LPM suffered from device-related complications like device dislodgement and device thrombus formation. Conclusion: The above findings suggest that while both the devices showed some device related risks, LPMs presented with fewer overall adverse outcomes, and thus, may be a safer alternative than conventional pacemakers. There is insufficient data on the use of LPM after valvular interventions. Further studies are required to fully assess the risks and benefits of LPM and their usage in patients of conduction abnormalities after valvular interventions.

Leadless pacemakers: The leap from single to dual chamber pacing

This study describes the acute and chronic effects of dual-chamber (DDD) pacing in 14 consecutive patients with hypertrophic obstructive cardiomyopathy (HOCM), whose symptoms were refractory to drug therapy. Although left ventricular (LV) outflow tract pressure gradients diminished from 106+/-47 to 62+/-33 mm Hg (p<0.001) by temporary pacing, the residual pressure gradients were >30 mm Hg in the majority of those with concomitant reductions in cardiac output. The DDD pacing was judged as insufficient by the acute study in the majority of patients. A dual-chamber pacemaker was, however, implanted in 11 patients, and the chronic pacing effects were evaluated. All symptoms (syncope, fainting, palpitation and dyspnea) subsided within 1 month. Left ventricular outflow tract pressure gradients diminished from 99+/-56 to 21+/-13 mm Hg (p<0.004) at 1 week after, and to 17+/-12 mm Hg (p<0.002) at 1 year after the implantation, as measured by Doppler echocardiography. Echocardiogram showed disappearance of the systolic anterior motion of the mitral valve, and significant regression of the septal hypertrophy (from 18.5+/-4.3 to 15.7+/-4.1 mm, p<0.04). There was no significant correlation between the acute and chronic pacing effects in the reduction of the pressure gradients or symptomatic improvement. These results suggest that DDD pacemaker implantation is an effective treatment without any serious risks for patients with drug-refractory HOCM. The chronic-pacing effect in the reduction of the pressure gradient, the regression of hypertrophy and symptomatic improvement cannot be predicted by the assessment of temporary DDD pacing.

Conduction abnormalities are common long-term sequelae after the Senning procedure for dextro-transposition of the great arteries (d-TGA), often requiring permanent pacing. Infection or lead malfunction may necessitate system extraction. Leadless pacemakers offer a promising alternative option. We present a 30-year-old man with d-TGA who previously underwent a Senning procedure. He had an infected pacemaker with lead extrusion. A combined procedure was performed, including complete system extraction and implantation of a leadless VDD pacemaker (Micra AV2). The procedure achieved atrioventricular (AV) synchrony and rapid recovery. This case highlights the viability of integrating leadless VDD pacemaker implantation with lead extraction in post-Senning d-TGA patients for efficient AV synchrony. It supports leadless pacing as practical solution for complex congenital cardiac anatomy. Leadless pacemakers represent a promising alternative pacing strategy for patients with d-TGA post-Senning procedure. Micra VDD pacing with AV synchrony represents an innovative and effective approach in this setting.

Leadless pacemaker (LP) technology was recently developed and introduced for clinical purpose as an alternative to traditional systems in order to reduce leads and pocket-related complications. Currently, two self-contained right ventricular pacemakers implanted by using a femoral percutaneous approach have been developed and initial results seem promising. Although the clinical use is still limited to the right ventricular pacing, the LP currently represents a valid and alternative solution in several settings, when the standard pacemaker cannot be used or its use is associated with higher risk of complications. Implementation of particular pacing algorithms in the near future will allow for a VDD pacing mode with only a single ventricular component, whereas the next evolution of technology will lead to develop multicomponent, communicating leadless systems capable to perform a dual-chamber pacing or even a cardiac resynchronization. The management after battery depletion is still controversial and experience on retrievability is anecdotic. Long term data from registry are necessary to reinforce the reliability of these systems in the real life and randomized trials comparing LPs with traditional pacemaker will be essential to better understand if the LP can become a new paradigm in cardiac pacing.

Leadless cardiac pacemaker (PM) implantation differs from conventional PM implantation. While the procedure has been considered safe, recent real-world data raised concerns about the learning curve of new operators and their implantation quality. The goal of this study was to investigate the influence of the first operator's experience on leadless PM implantation quality and procedural efficiency. We performed a bicentric analysis of all Micra TPS™ implantations in two large tertiary referral hospitals. We assessed both leadless PM implantation quality based on the absence of complications (requiring intervention or prolonged hospitalization), good electrical performance (pacing threshold ≤ 1.5 V/0.24 ms, R-wave amplitude > 5 mV), and acceptable fluoroscopy duration (<10 min) as well as procedural efficiency in relation to the operator's experience. Univariate and multivariate logistic regression analyses were performed to identify predictors for implantation quality and procedural efficiency. Leadless PM implantation was successful in 106/111 cases (95.5%). Three patients (2.7%) experienced acute complications (one cardiac tamponade, one femoral bleeding, one posture-related PM exit block). Multivariate analysis showed that implantation quality of more experienced first operators was higher [odds ratio 1.09 (95% confidence interval 1.00-1.19), P = 0.05]. Procedural efficiency increased with operator experience as evidenced by an inverse correlation of procedure time, time to the first deployment, fluoroscopy time, and the number of procedures performed (all P < 0.05). The operator's learning curve is a critical factor for leadless PM implantation quality and procedural efficiency.

Subcutaneous implantable cardioverter-defibrillators (S-ICDs) and leadless pacemakers (LPs) are intended to diminish transvenous lead-related complications. However, S-ICDs do not deliver antibradycardia pacing or antitachycardia pacing, and currently, there is no commercially available coordinated leadless option for patients with defibrillator and (expected) pacing needs. We evaluated the performance, safety, and potential replacement strategies of a novel modular cardiac rhythm management (mCRM) system, a wirelessly communicating antitachycardia pacing-enabled LP and S-ICD in a preclinical model. LP implantation was attempted in 68 canine subjects, and in 38 an S-ICD was implanted as well. Animals were evaluated serially up to 18 months. At all evaluations, communication thresholds (CTs) between the devices, LP electrical parameters, and system-related complications were assessed. Different replacement strategies were tested. The LP was successfully implanted in 67 of 68 (98.5%) and the concomitant S-ICD in 38 of 38 (100%). mCRM communication was successful in 1022 of 1024 evaluations (99.8%). The mean CT was 2.2± 0.7 V at implantation and stable afterward (18 months: 1.8± 0.7 V). In multivariable analysis, larger LP-to-S-ICD angle and dorsal posture were associated with higher CTs. At implantation, the mean pacing capture threshold, impedance, and R-wave amplitude were 0.3 ± 0.1 V, 898.4 ± 198.9 Ω, and 26.4± 8.2 mV. The mean pacing capture threshold remained stable and impedance and R-wave amplitudes were within acceptable ranges throughout (0.7± 0.4 V, 619.1 ± 90.6 Ω, and 20.1 ± 8.4 mV at 18 months). Different replacement strategies seem feasible. This first mCRM system demonstrated excellent performance up to 18 months in a preclinical model.

The AVEIR leadless pacemaker (LP) is a novel device that can function as a single atrial/ventricular or dual-chamber pacemaker. The introduction of single-chamber atrial LP has allowed electrophysiologists to treat patients with sinus node dysfunction with this device instead of implanting a dual-chamber transvenous pacemaker. We retrospectively identified all patients who underwent AVEIR LPs' implantation at Emory Healthcare between 2022 and 2025. Baseline characteristics, indications for pacing, and procedure outcomes were retrieved from electronic medical records. The device's electrical characteristics were reported from routine interrogations done at our device clinic. Between 2022 and 2025, 89 patients underwent implantation of 37 single-chamber atrial AVEIR, 34 single-chamber ventricular AVEIR, and 18 dual-chamber devices. Patients were followed for a median duration of 4.7 months [2;9]. The rate of major complications was 3.4% and minor complications 1.1%. Two patients with ventricular LP required upgrade to cardiac resynchronization therapy-defibrillator (CRT-D) due to pacing-induced cardiomyopathy (2.3%). One patient (2.7%) with a standalone atrial LP developed atrial fibrillation with slow ventricular response requiring the addition of a ventricular LP 10 months postimplantation. In our center, we adopted a modular pacing approach for leadless pacing. This strategy focuses on minimizing the amount of hardware in the heart. This reduces complications such as perforation and dislodgment while optimizing battery longevity, which is affected by i2i communication.