A comparison of procedure-related adverse events between two right ventricular leadless pacemakers.

INTRODUCTION: The Medtronic Micra VR and Abbott AVEIR VR are the leadless pacemakers (LPM) currently available in the United States (US). Micra VR employs fixation tines and the AVEIR VR uses an active fixation helix. Micra VR requires fixation before electrical measurements are obtained, while R-waves may be mapped by AVEIR VR without fixation. Little comparative data is available for these LPMs. Accordingly, we compared the incidences of procedure-related major adverse clinical events (MACE) and device problems in the US for Micra VR and AVEIR VR during 2022-2024. METHODS: We searched the FDA's Manufacturer and User Facility Device Experience (MAUDE) database for US reports of MACE and device problems that were filed from April 2022 to December 2023 for AVEIR VR, and from June 2022 to April 2024 for Micra VR. Totals for US-registered LPM implants were obtained from the manufacturers' product performance reports. RESULTS: During the study period, 5990 AVEIR VR and 10 940 Micra VR implants were registered in the US. We found 305 MAUDE reports for AVEIR VR (5.1%), versus 541 MAUDE reports for Micra VR (4.9%) (p = .702). The incidence of MACE was 0.72% (43/5990) for AVEIR VR versus 0.59% (65/10 940) for Micra VR, (p = .387). The incidences of procedure-related death, cardiac perforation. cardiac arrest, emergency pericardial drainage or reparative surgery were similar for both LPMs (p > .05). Micra VR had more unacceptable thresholds requiring LPM replacement compared to AVEIR VR (95;0.9% vs. 24;0.4%; p = .001). AVEIR VR had a statistically higher incidence of device dislodgement during (32) and after (21) implant compared to Micra VR (53 (0.9%) vs. 46 (0.4%), p < .001). CONCLUSIONS: Micra VR and AVEIR VR have similar procedural safety profiles, including the incidences of death and perforation. However, device problems differed significantly, possibly related to their design differences. Compared to Micra VR, AVEIR VR appears to have an advantageous threshold measurement capability but is more prone to device dislodgement.

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

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

Leadless pacemaker implantation using halo-shape technique in a severe dextroscoliosis octogenarian.

The halo-shape technique (HST) is an emerging approach for implanting a leadless pacemaker in scoliosis patients in recent years. Severe scoliosis and humpback made it challenging to push the tip of the delivery catheter towards the ventricular septum using the conventional gooseneck-shape technique. The feasibility and safety of the use of HST in an octogenarian with severe dextroscoliosis and humpback have not been well-assessed. Here, we report a case of high-degree atrioventricular block octogenarian with severe dextroscoliosis and humpback who successfully received a leadless pacemaker implantation using HST. Procedure-related complications were not observed, and the electrical parameters were stable at 6-month follow-up.

Conceptual Piezoelectric-Based Energy Harvester from In Vivo Heartbeats' Cyclic Kinetic Motion for Leadless Intracardiac Pacemakers.

This paper studies the development of piezoelectric energy harvesting for self-powered leadless intracardiac pacemakers. The energy harvester fit inside the battery compartment, assuming that the energy harvester would replace the battery with a smaller rechargeable battery capacity. The power output analysis was derived from the three-dimensional finite element analysis and in vivo heart measurements. A Doppler laser at the anterior basal in the right ventricle directly measured the heart's kinetic motion. Piezoceramics in the cantilevered configuration were studied. The heart motion was periodic but not harmonic and shock-based. This study found that energy can be harvested by applying periodic bio-movements (cardiac motion). The results also showed that the energy harvester can generate 1.1 V voltage. The effect of various geometrical parameters on power generation was studied. This approach offers potential for self-powered implantable medical devices, with the harvested energy used to power devices such as pacemakers.

Implantation techniques for a helix-fixation dual-chamber leadless pacemaker.

In a pivotal trial (NCT05252702), the AVEIR DR (Abbott) leadless pacemaker system was found to be safe and effective in delivering DDDR synchronous atrial and ventricular pacing. This dual-chamber system employs 2 leadless pacemakers with implant-to-implant communication. Although implantation of the ventricular device as a single-chamber pacemaker has been well described, there are additional considerations surrounding the dual-chamber implantation procedure. Herein, we review the dual-chamber leadless pacemaker implantation workflow while providing guidance to optimize safe and effective implantation procedures.

Retrievable dual-chamber leadless pacemaker implant (Aveir DR) in an adult patient with congenital heart disease.

Leadless pacemakers have demonstrated potential as a transvenous pacing option in Adult Congenital Heart Disease patients. Aveir™ single-chamber (VR) leadless pacemakers have demonstrated safety in patients without congenital heart disease in a dual chamber approach. We present a case of dual-chamber pacing using the Aveir dual-chamber (DR) leadless pacemaker in a patient with repaired dextro-transposition of the great arteries with ventricular septal defect (VSD) surgical closure. A 26-year-old male patient with a history of transposition of the great arteries status post arterial switch and VSD repair neonatally had complicated second degree atrioventricular block and sinus node dysfunction necessitating pacemaker placement. Epicardial single-chamber ventricular pacemaker was placed neonatally, which was switched to dual-chamber pacemaker at age 17 due to malfunction. Recent fracture of pacemaker leads led to implantation of new dual chamber leadless pacemaker. Removal of previous pacemaker leads via mechanical extraction occurred and implantation of Aveir DR leadless pacemaker was performed under anesthesia via right femoral vein access without complication. Follow-up demonstrated Aveir VR threshold of 1.0V@0.2 ms, R-wave of 8.9mV, impedance of 490Ω, and the Aveir AR threshold of 0.75V@0.2 ms, P-wave of 3.7mV, and impedance of 400Ω. This case demonstrates safety and efficacy of dual chamber leadless pacemaker implantation in an ACHD patient.

Management of Persistent Left Superior Vena Cava: Overcoming Lead and Vascular Complications With Transcatheter Pacing System Implantation.

Isolated persistent left superior vena cava (PLSVC) is a rare congenital anomaly typically found incidentally due to its asymptomatic nature. However, it can present technical challenges for device implanters. We report a case involving a patient with PLSVC, for whom the implantation of a transcatheter pacing system proved to be the most effective long-term solution. Although this venous anomaly initially provided a safe pacing route, it eventually led to early complications. The patient, a 78-year-old Puerto Rican man with hypertension, diabetes mellitus, and complete atrioventricular block, experienced multiple complications with pacing devices. After a failed left-sided pacemaker implant, a right-sided single-chamber ventricular device was placed, but it led to right ventricular lead fractures and was eventually abandoned. A new pacing system implanted in the left chest lasted only a year. Venography revealed a patent PLSVC with a previously implanted device now obstructed by an occluded left brachiocephalic vein. After laser-assisted extraction, a dual-chamber device was successfully implanted through the PLSVC. Despite unremarkable physical and lab results, the patient later showed syncope and high lead impedances with fractures in both leads and total PLSVC occlusion. A transcatheter pacing system was chosen to address the complex anatomical issues and abandoned hardware. Atrial synchronized pacing was confirmed the morning after implantation, and the patient was safely discharged. Ensuring a stable ventricular rhythm is crucial for patients with complete heart block. When hemodynamic stability is compromised by recurrent lead fractures and rare anatomical variants, implanters must consider alternative solutions. In this case, a transcatheter system was selected to avoid further lead and pocket-related complications and mitigate the risks of additional laser-assisted extractions. At the end of the device's lifespan, a new device can be implanted without significant anatomical issues, and the epicardial route remains a viable option if necessary.

Utilizing Leadless Pacemakers in Extremely Elderly Patients With a Conventional Pacemaker System: A Two-Year Follow-Up Case Series Without Generator Extraction in High-Risk Scenarios.

Background and objectives Leadless pacemakers, known for their safer clinical profile, offer significant advantages for elderly patients at a higher risk of complications associated with transvenous pacemaker procedures, particularly those susceptible to high-risk bleeding and infections related to cardiac implantable electronic device interventions. This study explores an alternative use of leadless pacemakers without removing existing transvenous systems, deviating from conventional generator replacement and lead re-interventions. Methods This study was conducted with full approval from the Institutional Review Board, Medical Ethical Committee, Centro Hospitalar Conde São Januário, Macau. Between January 2018 and December 2021, we conducted a retrospective case series involving extremely elderly individuals (aged 85 years or older) at a high risk of complications, necessitating either generator replacement or lead re-implantation. The study considered implanting a leadless pacemaker (Micra; Medtronic, Minneapolis, MN, USA) without removing the transvenous generator. For the primary endpoints, we evaluated procedure-related complications and clinical outcomes during hospitalization. Secondary endpoints included the stability of parameters and any unexpected interference or interactions between the two systems during the two-year follow-up. Results Eleven patients (aged 86-101) were enrolled, most receiving antiplatelet or anticoagulation therapy. Leadless pacemaker implantation proceeded without major complications or adverse clinical outcomes during hospitalization. Regular follow-up was conducted every three to six months for adjusting pacemaker parameters and interrogating each patient. Over two years, three patients died from non-cardiac causes: two from infection and one from spontaneous intracranial hemorrhage, while eight completed regular follow-ups. We didn't detect any episodes of ventricular arrhythmias or intracardiac capture from the transvenous pacemaker system. We observed the stability in both the longevity and the voltage of the conventional generator battery, maintaining similar parameters without significant depletion (mean voltage decline: -0.07V/year). Parameters of the leadless pacemaker remained consistently normal without interference with existing pacing systems. Conclusion Implanting leadless pacemakers without removing transvenous pacemaker generators appears safe and effective for extremely elderly patients who are at high risk of complications. Comprehensive two-year follow-up supports the safety and viability of this approach. Opting for this approach instead of conventional generator replacement, with or without additional lead implantation, may be reasonable in this population. However, further research within this patient cohort, such as exploring long-term outcomes beyond two years or comparing clinical outcomes with conventional strategies, may be necessary.

Optimizing electrical efficacy of leadless cardiac resynchronization therapy and leadless left ventricular septal pacing: Insights on left and right ventricular activation from electrocardiographic imaging.

Background: Leadless cardiac resynchronization therapy (CRT) is an emerging heart failure treatment. An implanted electrode delivers lateral or septal endocardial left ventricular (LV) pacing (LVP) upon detection of a right ventricular (RV) pacing stimulus from a coimplanted device, thus generating biventricular pacing (BiVP). Electrical efficacy data regarding this therapy, particularly leadless LV septal pacing (LVSP) for potential conduction system capture, are limited. Objectives: The purpose of this study was to evaluate the acute performance of leadless CRT using electrocardiographic imaging (ECGi) and assess the optimal pacing modality (OPM) of LVSP on the basis of RV and LV activation. Methods: Ten WiSE-CRT recipients underwent an ECGi study testing: RV pacing, BiVP, LVP only, and LVP with an optimized atrioventricular delay (LV-OPT). BiV, LV, and RV activation times (shortest time taken to activate 90% of the ventricles [BIVAT-90], shortest time taken to activate 95% of the LV, and shortest time taken to activate 90% of the RV) plus LV and BiV dyssynchrony index (standard deviation of LV activation times and standard deviation of all activation times) were calculated from reconstructed epicardial electrograms. The individual OPM yielding the greatest improvement from baseline was determined. Results: BiVP generated a 23.7% improvement in BiVAT-90 (P = .002). An improvement of 43.3% was observed at the OPM (P = .0001), primarily through reductions in shortest time taken to activate 90% of the RV. At the OPM, BiVAT-90 improved in patients with lateral (43.3%; P = .0001; n = 5) and septal (42.4%; P = .009; n = 5) LV implants. The OPM varied by individual. LVP and LV-OPT were mostly superior in patients with LVSP, and in those with sinus rhythm and left bundle branch block (n = 4). Conclusion: Leadless CRT significantly improves acute ECGi-derived activation and dyssynchrony metrics. Using an individualized OPM improves efficacy in selected patients. Effective LVSP is feasible, with fusion pacing at LV-OPT mitigating the potential deleterious effects on RV activation.

Left ventricular electrical delay predicts volumetric response to leadless cardiac resynchronization therapy.

BACKGROUND: Leadless left ventricular (LV) endocardial pacing is an emerging cardiac resynchronization therapy (CRT) technology. Predictors of response to leadless CRT are poorly understood. Implanting the LV endocardial pacing electrode in sites with increased electrical latency (Q-LV) may improve response rates. OBJECTIVE: The purpose of this study was to examine the association between Q-LV and echocardiographic remodeling response to leadless CRT delivered with the WiSE-CRT system. METHODS: A post hoc analysis (n = 122) of the SOLVE-CRT trial examined the relationship between LV pacing site Q-LV with rate of left ventricular end-systolic volume (LVESV) reduction >15% at 6 months. Multivariable regression analysis, adjusting for age, sex, previous CRT nonresponse, cardiomyopathy etiology, QRS morphology, and QRS duration was performed, followed by receiver operating characteristic analysis and analysis of variance by Q-LV quartile. A subgroup analysis of the ischemic cardiomyopathy cohort was undertaken. RESULTS: Complete Q-LV data were available for 122 of 153 patients (80%) in the active arms SOLVE-CRT. Overall, the 6-month LVESV response rate was 46%. Logistic regression identified Q-LV as an independent response predictor with borderline significance (adjusted odds ratio 1.015; P = .05). Analysis by Q-LV quartile demonstrated a significant improvement in response rate in quartile 4 (longest Q-LV 64%) compared to quartile 1 (shortest Q-LV 28%) (P <.01). This association was primarily driven by strong Q-LV-response correlation in patients with ischemic cardiomyopathy, demonstrated by subgroup logistic regression (adjusted odds ratio 1.034; P = .004). CONCLUSION: Increased Q-LV was associated with improved reverse remodeling following leadless CRT. Targeting LV endocardial sites of high Q-LV may deliver additional benefit compared to empirical LV electrode implantation.