Lead Tip Research Articles

Use of a Stylet Driven Lead With a Flexible Neck for Left Bundle Branch Area Pacing: A Single Center Experience.

The majority of data on left bundle branch area pacing (LBBAP) are on a lumenless lead. Data on the safety and effectiveness of stylet driven leads are comparatively lacking. We retrospectively analyzed 265 patients who underwent attempted LBBAP with an 7842 (Boston Scientific, Marlborough, MA) lead in the Duke University Health System between 1/1/2020 and 9/1/2023. Outcomes of interest included post-operative 7842 helix extension (≥2 helix rotations beyond the lead tip), complications, and lead parameters. A nested analysis of single and dual chamber LBBAP attempts was performed to compare outcomes among similar patients who underwent attempted LBBAP with the lumenless 3830 (Medtronic, Mineappolis, MN) lead. LBBAP success with 7842 was 89.8%. Characteristics were similar among patients with (n = 238) and without (n = 27) successful implants. Helix extension was evaluable for 222 of 238 successful 7842 implants. Of evaluable leads, helix extension was complete for 174 leads (78%), and partial for 48 (21.6%). A trend towards lower dislodgement rates was observed in patients with full versus partial extension (2.9% vs. 8.3%, p = 0.0895) and the rate of full helix extension increased over time (64.1% over 24 months vs. 81.4% over 21 months, p = 0.0162). The success rate of 3830 LBBAP implants (n = 140) was 92.8% (p = 0.069 vs. 7842). At implant, R waves were similar for 7842 and 3830 leads but were greater for 7842 during follow-up (14.4 + /-0.77 vs. 11.3 + /-0.68, p = 0.004). Pacing impedances were higher with 7842 compared with 3830 at baseline (838 + /-10.44 ohms vs. 772 + /-14.58 ohms, p < 0.001) and during follow-up (652 + /-11.0 ohms vs. 513 + /-9.18 ohms, p < 0.001); similarly, 7842 pacing thresholds (@ 0.4 ms) were slightly higher at baseline (0.85 V + /-0.03 vs. 0.68 V + /-0.03, p < 0.001) and 6 months (0.95 V + /-0.03 vs. 0.80 V + /-0.03, p < 0.001) compared with those for the lumenless 3830. LBBAP implant success rates, complications, and pacing parameters using the 7842 lead are stable over time, and appeared overall similar to the 3830 lead. Incomplete 7842 helix extension is a modifiable risk factor for lead dislodgement.

Intraprocedural transthoracic EChocardiography to facilitate Left Bundle Branch Pacing: EC-LBBP.

Left bundle branch (LBB) pacing (LBBP) has gained rapid adoption. Evidence for direct LBB capture has varied from 30%-95% depending on the criteria. The purpose of this study was to assess the feasibility and efficacy of intraprocedural transthoracic echocardiographic guidance to achieve LBB capture. This was a prospective, nonrandomized, case-control study (ClinicalTrials.gov Identifier: NCT05646251). The pectoral region including echocardiographic windows were sterile-draped using Ioban. The lead was placed in the right ventricular septum and sheath orientation adjusted under echocardiography. The lead was advanced under echocardiographic visualization until the tip reached the left ventricular subendocardium. LBB capture was strictly defined: transition from nonselective to selective/left ventricular septal capture; LBB potential with injury current; and Delta (HBP-LBBP) V6RWPT ≥10. Thirty patients underwent echocardiography-guided left bundle branch pacing (EC-LBBP) and compared with 30 patients (standard approach): mean age 74.4 ± 10 years; female 45%; hypertension 92%; cardiomyopathy 43%; atrioventricular block/atrioventricular nodal ablation 75%. Total procedural and fluoroscopy durations were similar. Left bundle branch area pacing (LBBAP or left ventricular septal pacing) was successful in all patients in both groups. EC-LBBP was 97% successful in achieving LBB capture vs 70% (P = .02) with LBB potentials (LB-V 23 ± 6 ms) in 95% vs 77% (22 ± 6 ms). Morphology transition confirming LBB capture was seen in 87% vs 67% (P = .02). Lead tip was visualized at the left ventricular subendocardium in 100% of patients in EC-LBBP. EC-LBBP was 97% successful in achieving LBB capture using strict criteria. LBBP lead was subendocardial in all patients. EC-LBBP is practical, feasible, safe, and highly effective in achieving LBB capture.

Electrophysiological Characteristics and Mechanism of His-Bundle Pacing Guided by Electrocardiograms in Uninterrupted Real-Time Monitoring Technique.

His-bundle pacing (HBP) is a pacing mode that provides near-physiological pacing and has more advantages over standard right ventricle (RV) septum pacing in positive clinical results. However, traditional HBP cannot accurately and stably place the lead tip into the His-Purkinje system. Hence, this study aimed to establish a novel strategy for HBP to strike a balancebetween an excellent pacing threshold and minor injuries to the conduction system. HBP, using continuous and real-time monitoring of unipolar His-bundle (HB) electrograms along with electrocardiograms, was performed in 29 consecutive atrial fibrillation patients. We analyzed the unipolar HB intracardiac electrogram (EGM) and electrophysiological characteristics during HBP using John Jiang's connecting cable and an electrophysiology recording system. All patients were followed up for 12 months. Of the 29 patients, 28 (96.55%) successfully received HBP. Twenty-one (75%) patients were confirmed to have the negative deflection of His potential with a negative amplitude of ≥ 0.1mV in HB EGM. The subgroup with a deep negative deflection was recorded with an HBP threshold (0.71 ± 0.41V), significantly lower than those thresholds with no deep negative deflection (1.83 ± 0.76V) (p < 0.05). The selective HBP rate was significantly different between the two groups: 20 (95.24%) in the deep negative deflection group and three (42.86%) in thenon-deep negative deflection group (p < 0.05); five (17.24%) patients presented right bundle branch block (RBBB) during the lead placement. This study supports the safety and feasibility of using an uninterrupted real-time monitoring technique for HBP. An uninterrupted real-time monitoring technique can guide theaccurate placement of the HB lead and may provide abalancebetween anexcellent pacing threshold and minor injury to the conduction system.

Joint Anatomical, Histological, and Imaging Investigation of the Midbrain Target Region for Superolateral Medial Forebrain Bundle Deep Brain Stimulation

Introduction: Deep brain stimulation (DBS) of the superolateral branch of the medial forebrain bundle (slMFB) is currently being researched in clinical trials and open case series as a therapeutic option for treatment-resistant major depressive disorder and treatment-resistant obsessive-compulsive disorder (TR-OCD). There are numerous publications describing stimulation in such proximity to the ventral tegmental area (VTA) and open questions remain concerning the stimulation target and its functional environment. As of right now, we are not aware of any publications that compare the typical electrode placements with the histologically supported tractographic depiction of the target structure. Methods: We used three cadaver midbrain samples with presumed unaltered anatomy. After fixation, staining and slicing, the histological samples were warped to the Montreal Neurological Institute (MNI) big brain environment. Utilizing a tractographic atlas, a qualitative analysis of the typical slMFB stimulation site in the lateral VTA utilizing a subset of clinically implanted DBS electrodes in n = 12 patients, successfully implanted for TR-OCD was performed. Results: A joint qualitative overlay analysis of predominantly tyrosine hydroxylase stained histology at different resolutions in an anatomical common space was achieved. Localization of the DBS lead bodies was found in the typical positions in front of the red nuclei in the lateral VTA. DBS lead tip region positions explained the oculomotor side effects of stimulation related to paranigral or parabrachial pigmented sub-nuclei of the VTA, respectively. The location of active electrode contacts suggests downstream and antidromic effects on the greater VTA related medial forebrain bundle system. Conclusion: This is the first dedicated joint histopathological overlay analysis of DBS electrodes targeting the slMFB and lateral VTA in a common anatomical space. This analysis might serve to better understand the DBS target region for this procedure.

Comparison of electrocardiogram parameters and echocardiographic response between distinct left bundle branch area pacing modes in heart failure patients.

Left bundle branch area pacing (LBBAP) has become an alternative method for cardiac resynchronization therapy. Various modes of LBBAP have been determined, including left bundle trunk pacing (LBTP), left anterior branch pacing (LAFP) and left posterior branch pacing (LPFP). However, whether the outcomes of various pacing modes differ in heart failure (HF) patients is still unclear. This study aimed to compare the electrophysiological characteristics and echocardiographic response rate among those distinct modes of LBBAP. HF patients undergoing successful LBBAP were retrospectively included. Distinct modes of pacing were determined based on paced QRS morphology. The fluoroscopic images were collected to compare the lead tip position between the groups. The electrocardiograms (ECG) before and after LBBAP were used to measure the depolarization (QRS duration [QRSd] and the interventricular delay [IVD]), and the repolarization parameters [QTc, TpeakTend(TpTe), and TpTe/QTc]. The left ventricular ejection fraction (LVEF) and left ventricular end-diastolic diameter (LVEDD) of patients were also recorded. In addition, the lead parameters and certain complications were compared. A total of 64 HF patients were finally included, consisting of 16 (25.0%) patients in the LBTP group, 22 (34.4%) patients in the LAFP group, and 26 (40.6%) patients in the LPFP group. The distribution features of LBBAP lead tips were significantly related to pacing modes: LBTP was more likely to be in zone 4 while LAFP or LPFP was prone to locate in zone 5. After LBBAP, the ventricular ECG parameters were significantly improved, regardless of pacing modes. Besides, the LVEF of the patients was significantly increased (P < 0.001), and LVEDD was significantly decreased (P < 0.001). There was no difference in the response rate and super-response rate among groups (P > 0.05). In addition, the lead parameters remained stable and no significant difference was observed among groups. LPFP was the main pacing mode among HF patients after LBBAP. The paced QRS morphology was significantly related to the position of lead tips. After LBBAP, the ventricular depolarization synchronization and repolarization stability were both significantly improved, regardless of pacing modes. There was no significant difference in the echocardiographic response rate among distinct LBBAP modes.

Removal of leads broken during extraction: A comparison of different approaches and tools.

Extraction of a broken lead fragment (BLF) has received scant attention in the literature. Retrospective analysis was to compare the effectiveness of different approaches and tools used for BLF removal during 127 procedures. A superior approach was the most popular (75.6%), femoral (15.7%) and combined (8.7%) approaches were the least common. Of 127 BLFs 78 (61.4%) were removed in their entirety and BLF length was significantly reduced to less than 4 cm in 21 (16.5%) or lead tip in 12 (9.4%) cases. The best results were achieved when BLFs were longer (>4 cm) (62/93 66.7% of longer BLFs), either in the case of BLFs free-floating in vascular bed including pulmonary circulation (68.4% of them) but not in cases of short BLFs (20.0% of short BLFs). Complete procedural success was achieved in 57.5% of procedures, the lead tip retained in the heart wall in 12 cases (9.4%) and short BLFs were found in 26.0%, whereas BLFs >4 cm were left in place in four cases (3.1%) of procedures only. There was no relationship between approach in lead remnant removal and long-term mortality. (1) Effectiveness of fractured lead removal is satisfactory: entire BLFs were removed in 61.4% (total procedural success-57.5%, was lower because five major complications occurred) and BLF length was significantly reduced in 26.0%. (2) Among the broken leads, leads with a long stay in the patient (16.3 years on average), passive leads (97.6%) and pacemaker leads 92.1% are significantly more common, but not ICD leads (only 7.9% of lead fractures) compared to TLE without lead fractures. (3) Broken lead removal (superior approach) using a CS access sheath as a "subclavian workstation" for continuation of dilatation with conventional tools deserves attention. (4) Lead fracture management should become an integral part of training in transvenous lead extraction.

Modeling and measurement of lead tip heating and resonant length for implanted, insulated wires.

To study implant lead tip heating because of the RF power deposition by developing mathematical models and comparing them with measurements acquired at 1.5 T and 3 T, especially to predict resonant length. A simple exponential model and an adapted transmission line model for the electric field transfer function were developed. A set of wavenumbers, including that calculated from insulated antenna theory (King wavenumber) and that of the embedding medium were considered. Experiments on insulated, capped wires of varying lengths were performed to determine maximum temperature rise under RF exposure. The results are compared with model predictions from analytical expressions derived under the assumption of a constant electric field, and with those numerically calculated from spatially varying, simulated electric fields from body coil transmission. Simple expressions for the resonant length bounded between one-quarter and one-half wavelength are developed based on the roots of transcendental equations. The King wavenumber for both models more closely matched the experimental data with a maximum root mean square error of 9.81°C at 1.5 T and 5.71°C at 3 T compared to other wavenumbers with a maximum root mean square error of 27.52°C at 1.5 T and 22.01°C for 3 T. Resonant length was more accurately predicted compared to values solely based on the embedding medium. Analytical expressions were developed for implanted lead heating and resonant lengths under specific assumptions. The value of the wavenumber has a strong effect on the model predictions. Our work could be used to better manage implanted device lead tip heating.

Lead break during extraction - predisposing factors and impact on procedure complexity and outcome on the basis of analysis of 3825 procedures

Abstract Background There are no reports describing lead break (LB) during transvenous lead extraction (TLE). Our aim was to compare the effectiveness of different approaches and tools used for LB removal during 127 procedures. Methods Retrospective analysis of 3825 consecutive TLEs using mechanical sheaths. Results Fracture of the lead defined as LB with a long lead fragment (LF) occurred in 2.48%, LB with a short LF in 1.20%, LB with the tip of the lead in 1.78% and LB with loss of a free-floating LF in 0.57% of cases. In total, extractions with LB occurred in 6.04%. In cases in which lead remnant was equivalent to a lead fragment (more than the lead tip only) there was a 50.31% chance of removing the LF in its entirety and an 18.41% chance of significantly reducing its length (to less than 4 cm). Risk factors for LB are similar to those for major complications and increased procedure complexity: long lead dwell time [OR=1.018], higher LV ejection fraction, multiple previous CIED-related procedures and extraction of passive fixation leads. A superior approach was the most popular (75.59%), femoral (15.75%) and combined (8.66%) approaches were the least common. Broken lead fragments (BLFs) were removed in their entirety in 63.78% and BLF length was significantly reduced (to less than 4 cm) in 24.41%. The best results were achieved when BLFs were longer (&amp;gt;4 cm) (66.67%), either free-floating or in the pulmonary circulation (68.42%) but not in cases of short BLFs (20.0%). Complete procedural success was achieved in 70.87% of procedures, the lead tip retained in the heart wall and short BLFs were found in 25.98%, whereas BLFs &amp;gt; 4 cm were left in place in 3.15% of procedures only. There was no relationship between approach in lead remnant removal and long-term mortality. All forms of LB were associated with increased procedure complexity and major complications (9.96% and 1.53%). There was no procedure-related death among such patients and LB did not affect survival after TLE. Conclusions 1. LB during TLE occurs in 6.04% of procedures and it increases procedure complexity and risk of major complications. Thus, the possibility of LB should be taken into account when planning lead extraction strategy and training. 2. Effectiveness of fractured lead removal is satisfactory. 3.Risk factors for lead fracture are implant duration (16.27 years on average), ventricular leads (71.65%), passive fixation leads (97.63%) and pacemaker leads (92.13%), but not ICD leads (only 7.87% of lead fractures). 4. Broken lead removal using a coronary sinus access sheath as a "subclavian workstation" for continuation of dilatation with conventional tools deserves attention.

Single-center experience with His bundle lead implantation: success rate, implantation method optimization, and lessons learned in 426 patients

Abstract Background Conduction system pacing (CSP) is increasingly used to avoid the development of pacing-induced cardiomyopathy in patients who require a high amount of ventricular pacing. His bundle pacing (HBP) is considered as ideal to achieve the narrowest paced QRS and optimal synchronization in patients with intrinsic narrow QRS or right bundle branch block but also as difficult at implantation. Purpose We analyzed our experience with HBP in terms of time and effort, pacing and sensing results, success rate, and lessons learned for optimization over a time period of 7 years. Methods All consecutive patients in whom HBP was attempted between 6/2016 and 11/2023 were included in this analysis. Implantations were performed using a pacing system analyzer (PSA) with high-resolution electrograms (EGMs). Data on implantation success [selective or non-selective HBP, left bundle branch area pacing (LBBAP)], sensing and pacing parameters, achievement of His bundle current of injury (coi), duration of implantation and fluoroscopy were collected prospectively. These results were compared for the 1st, 2nd, 3rd and 4th quartile of implantations and reasons for improvement or deterioration were analyzed. Results HBP was attempted in 426 patients (78±11 years, 38% female, 90% AV block, left ventricular ejection fraction 54±10 %, 81 single-, 286 dual-, 46 triple-chamber pacemakers, 2 dual- and 11 triple-chamber ICDs) and was successful in 404 patients (95%): 182 non-selective HBP, 206 selective HBP, and 16 LBBAP. R wave amplitude was 4.5±3.5 mV, pacing threshold 1.1 ± 0.6V/1.0 ms. In 16% of patients, a ventricular back-up lead was implanted. A His bundle coi was achieved in 61% of patients. The implantation duration was 92±43 min, fluoroscopy duration 10±8 min. Success rate increased from 89% in the 1st to 99% in the 4th quartile. Improved implantation success was associated with using a stiff 3D steerable sheath, implantation site at the distal His bundle, and an increased number of screw-in turns until a His bundle coi was visible. Conclusions Establishing an implantation routine with 1) a PSA and high-resolution EGMs, 2) use of a stiff 3D steerable sheath, 3) implantation at the distal His bundle with myocardial capture (non-selective HBP) as a back-up, and 4) an increased number of screw-in turns of the lead tip until a His bundle coi is achieved, HBP implantation can be facilitated and results optimized to a highly acceptable implantation effort and a success rate &amp;gt;95%.

Pulsed field ablation in patients with cardiac implantable electronic devices: an ex vivo assessment of safety.

Pulse field ablation (PFA) is a novel catheter ablation technology with potential safety benefits due to its tissue selectivity. It has the potential to directly damage or interact with the functionality of cardiac implantable electronic devices (CIEDs) in the form of electromagnetic interference (EMI). The aim of our study was to assess the impact of PFA on CIEDs. PFA lesions (45 per CIED) were applied from the Farapulse system to CIEDs (< 5 cm from the lead tip and < 15 cm from the generator). All devices were checked before and after PFA application for proper sensing and pacing functionality as well as for integrity of shock circuits in ICDs using a heart simulator. Moreover, devices were then interrogated for any spontaneous reprogramming, mode switching or other EMI effects. In total, 44 CIEDs were tested (16 pacemaker, 21 ICDs, 7 CRT-P/D) with 1980 PFA applications. There was no change in device settings, functionality and electrical parameters, and there was no macroscopic damage to the devices. The risk of damage to the electric components or leads on a patient-based analysis is 0/44 (95% CI 0-8%) and on a PFA pulse-based analysis is 0/1980 (95% CI 0-0.2%). Clinically relevant EMI appeared with oversensing and pacing inhibition but not tachycardia detection. Bipolar PFA appears safe and does not result in damage to CIEDs or leads. Clinically relevant EMI does occur, but appropriate peri-procedural programming may mitigate this. In vivo studies are needed to confirm our findings.

Impact of lead position on tricuspid regurgitation, ventricular function, and heart failure exacerbation and mortality after cardiac implantable electronic device implantation. Preliminary results from the PACE-RVTR Registry.

The most frequent mechanism of lead-related tricuspid regurgitation (LRTR), which occurs in 7.2% to 44.7% of patients implanted with a cardiac implantable electronic device (CIED), is leaflet impingement or the restriction of its movement by a ventricular lead. It is unclear if the position of the lead tip - in the right ventricular apex (RVA) or other location (non-RVA) - has any influence on the development of LRTR. The study aimed to determine the impact of the CIED lead tip position on the development or progression of tricuspid regurgitation (TR) and its potential impact on heart failure exacerbation and mortality. One hundred and two consecutive patients who received CIEDs between March 2020 and October 2021 were included in the prospective registry (PACE-RVTR). Patients were assigned to two groups depending on the lead position - the RVA group and the non-RVA group. All patients underwent echocardiographic evaluation before implantation and one year later. In terms of baseline clinical characteristics, the two groups did not differ. Before CIED implantation, patients in the non-RVA group had better left ventricular systolic function (P = 0.004). Pacemakers were implanted more often in the non-RVA group (P = 0.001) while implantable cardioverter-defibrillators in the RVA group (P = 0.008). Progression to severe or massive TR was more common in the non-RVA group (P = 0.005). Severe and massive TR occurred more often in patients with the non-RVA position of the lead. The right ventricular lead position did not impact heart failure progression or all-cause mortality at two-year follow-up.

Strategies to maximize lead tensile strength during extraction in three families of pacing leads

BackgroundTraction force that can be applied to an extraction rail is based on lead tensile strength, a product of its construction. A strong rail allows safe advancement of the extraction sheath. This study expands previous work providing strategies to optimize INGEVITY rail strength. ObjectiveThe purpose of this study was to measure forces that leads encounter in a simulated extraction procedure, determine lead response, and develop extraction recommendations for INGEVITY, INGEVITY+, and FINELINE II lead families. MethodsLeads were positioned in a simulated right atrial appendage implant. Subsequent traction forces enabled evaluation of lead tensile strength and effectiveness of preparation/extraction techniques. ResultsSignificant findings include (1) preserving the lead terminal pin did not decrease lead tensile strength and typically maximized it; (2) the weakest region is between the cathode and anode; (3) mid lead scar increases traction force tolerance until that scar is removed; and (4) optimal rail strength was observed using a multivenous approach with a femoral snare. Unique lead family findings include increased tensile strength of FINELINE II polyurethane vs silicone and INGEVITY active fixation vs passive fixation. ConclusionThis study teaches the implanting clinician there are specific extraction techniques available to improve the removal of leads that may be the best option for a patient's clinical needs. Bench testing demonstrates that lead construction drives lead behavior during an extraction. Preserving the lead terminal pin provides consistent and, in most cases, optimal rail strength. If clinically indicated, a multivenous approach using a femoral snare significantly increases rail strength and protects the vulnerable lead tip.

Assessing Torque Transfer in Conduction System Pacing: Development and Evaluation of an Ex Vivo Model

BackgroundConduction system pacing (CSP) faces challenges in achieving reliable and safe deployments. Complex interactions between tissue and lead tip can result in endocardial entanglement, a drill effect that prevents penetration. No verified ex vivo model exists to quantitatively assess this relationship. ObjectivesThe purpose of this study was to quantitatively characterize CSP lead tip to tissue responses for 4 commonly used leads. MethodsCSP leads (from Medtronic, Biotronik, Boston Scientific, and Abbott) were examined for helix rotation efficiency in ex vivo ovine right ventricular septa. A custom jig was utilized for rotation measurements. Fifteen turns were executed, documenting tissue-interface changes every 90° using high-resolution photography. Response curves (input rotation vs helix rotation) were evaluated using piecewise linear regression, with a focus on output vs input response slopes and torque breakpoint events. ResultsWe analyzed 3,840 quarter-turn CSP insertions with 4 different lead types. Helix rotations were consistently less than input: Abbott Tendril = 0.21:1, Medtronic 3830 = 0.21:1, Biotronik Solia = 0.47:1, and Boston Scientific Ingevity = 0.56:1. Torque breakpoint events were observed on average 7.22 times per insertion (95% CI: 6.08-8.35; P = NS) across all leads. In 57.8% of insertions (37 of 64), uncontrolled torque breakpoint events occurred, signaling unexpected excess helix rotations. ConclusionsUsing a robust ex vivo model, we revealed a muted helix rotation response compared with input turns on the lead, and frequent torque change events during insertion. This is critical for CSP implanters, emphasizing the potential for unexpected torque breakpoint events, and suggesting the need for novel lead designs or deployment methods to enhance CSP efficiency and safety.

2401. The Role of Quantitative Microbial Cell-free DNA (mcfDNA) Sequencing (Seq) from Plasma in the Diagnosis (Dx) of Staphylococcal Cardiac Implantable Electronic Device Infective Endocarditis (CIED IE)

Abstract Background Optimal treatment (rx) of staphylococcal CIED IE requires removing the entire CIED. Difficulty of dx plus cost and potential morbidity of rx make treatment challenging. Complicated staphylococcal bacteremia is associated with prolonged detection of plasma mcfDNA during antibiotic rx. To assess for IE, we studied plasma mcfDNA kinetics in CIED patients (pts) with staphylococcal bacteremia undergoing CIED removal. Methods With written consent, CIED pts (no persistent confounding infection) with bacteremia in the prior ≤ 7 days (d) and planned CIED removal had serial plasma specimens collected [Figure]. Quantitative mcfDNA-Seq was done using the Karius Test® at Karius CLIA certified Laboratory (Redwood City,CA) on batched pt specimens. Clinical data were obtained from the electronic medical record. CIEDs were removed through sterile pockets or surgically except in pt 012. Definite CIED IE was defined by multiple d of bacteremia plus a definite lead / tricuspid vegetation per echocardiogram, direct inspection or lead tip culture; multiple d bacteremia or a definite vegetation defined possible CIED IE. Results Nine pts with definite CIED IE had bacteremia 3-13 d (median 6 d) with Staphylococcus aureus (7 pts) or S. epidermidis (2 pts: 012 who due to retained lead fragment relapsed after rx 021) [Table 1]. At consent, after 2-11 d rx (median 6 d) mcfDNA was detected in 8 of 9 pts; in all 9, on CIED extraction mcfDNA increased significantly from consent and pre-extraction levels [Table3]. Five pts with possible S.aureus CIED IE had 1-3 d (median1 d) bacteremia [Table 2]. None had plasma mcfDNA after 5 d rx and 4 of 5 had no mcfDNA detectable on device extraction [Table3]. McfDNA patterns in definite CIED IE (8 of 9 pos on consent / pre-extraction and had an increase on extraction) differed from those in possible CIED IE (4 of 5 neg at 5 d of rx and none detected on extraction) [p=0.023 Fisher Exact]. Conclusion Quantitative mcfDNA patterns can help distinguish definite from possible CIED IE and absence of mcfDNA in plasma of possible CIED IE on device extraction suggests that the CIED may not be infected. After 5 days of rx, plasma mcfDNA-Seq in CIED pts with staphylococcal bacteremia coupled with clinical features may identify patients that can be effectively treated without device removal - a testable hypothesis. Disclosures Adolf W. Karchmer, MD, DeBiopharma: Advisor/Consultant|DeBiopharma: Honoraria|Karius: Grant to Institution for this study Jason D. Matos, MD, Merck: Wife is an employee Nicholas R. Degner, MD, MPH, MS, Karius: Employer

Animal study on left bundle branch current of injury and anatomic location of leads in His-purkinje conduction system pacing

Objective: Explore the relationship between tip of the left bundle branch pacing lead and anatomic location of left bundle branch as well as the mechanism of left bundle branch current of injury. To clarify the clinical value of left bundle branch current of injury during operation. Methods: The pacing leads were implanted in the hearts of two living swines. Intraoperative electrophysiological study confirmed that the left bundle branch or only the deep left ventricular septum was captured at low output. Immediately after operation, the gross specimen of swine hearts was stained with iodine to observe the gross distribution of His-purkinje conduction system on the left ventricular endocardium and its relationship with the leads. Subsequently, the swine hearts were fixed with formalin solution, and the pacing leads were removed after the positions were marked. The swine hearts were then sectioned and stained with Masson and Goldner trichrome, and the relationship between the anatomic location of the conduction system and the tip of the lead was observed under a light microscope. Results: After iodine staining of the specimen, the His-purkinje conduction system was observed with the naked eye in a net-like distribution, and the lead tip was screwed deeply and fixed in the left bundle branch area of the left ventricular subendocardium in the ventricular septum. Masson and Goldner trichrome staining showed that left bundle branch pacing lead directly passed through the left bundle branch when there was left bundle branch potential with left bundle branch current of injury, while it was not directly contact the left bundle branch when there was left bundle branch potential without left bundle branch current of injury. Conclusion: The left bundle branch current of injury observed on intracardiac electrocardiogram during His-purkinje conduction system pacing suggests that the pacing lead directly contacted the conduction bundle or its branches, therefore, the captured threshold was relatively low. Left bundle branch current of injury can be used as an important anatomic and electrophysiological evidence of left bundle branch capture.

Lower intercostal spaces depicted better final r wave than V1 at left bundle branch pacing implant attempts

Abstract Background Left bundle pacing lead positioning implies screwing the lead until a final ‘r’ wave is seen in V1 ECG lead (unipolar pacing), depicting the left part of the septum has been reached. That final vector should be better seen if V1 is placed parallel rather than perpendicular to the lead tip, so we used lower intercostal spaces for V1, to test this hypothesis. Failure to see the 'r' wave could increase the screwing efforts owing to perforation. Methods Leads V1 to V5 were positioned from 2nd to 6th right sided intercostal spaces during implants. Fluoroscopy was used to ascertain the lead most parallel to the final tip position. Inferior leads were used to confirm anterior, mid or posterior implants. A ratio between the ‘r’ wave amplitude and the QRS amplitude was used to compare the intercostal space depicting better the final ‘r’ wave. Results 19 patients were implanted using this new set-up of precordial leads (see figure 1); 32% were female; mean age at implant was 77,6 +/-8,04 years (range 58,3-90,6 years old); all but two were Medtronic 3830 leads. Regarding the position 26%, 32% and 42% of the leads ended in the posterior, mid or anterior septum respectively. Mean unipolar pacing QRS was 126ms +/- 18,2ms and mead LVAT was 76ms +/-19ms. Only 31% of patients had the lead placed parallel to the 4th intercostal space; 13% had the lead parallel between the 4th and the 5th space; and 56% of implants, had the 5th or 6th space as the most parallel to the lead tip. Finally in a consistent way, mean ratios of ‘r’/QRS amplitude were increasing at every intercostal space from: 0,12/2nd; 0,24/3rd; 0,3/4th; 0,35/5th and 0,45/6th (except for most posterior implanted leads where ratios varied less); this finding was even greater for anterior implanted leads (see figure 2). Conclusion Final ‘r’ wave is better depicted when V1 is lowered to 5th or 6th intercostal space, as the leads are mostly implanted parallel to these observation sites; but the septum is also a 3-D structure and when the leads are implanted too anterior, there is almost no way to see the final ‘r’ wave in usual 4th space V1, as the vector is directed mostly in the opposite direction (posteriorly and downward), while a lower placed V1 allows some of that vector to be depicted anyways. Placing V1-V3 leads in 4th-6th intercostal spaces could prevent excessive screwing and reduced perforation rates specially in anterior implanted leads.LAO: V1 to V5 placed 2-6 R intercostal'r' not seen until 5th-6th R intercostal

Abstract 16739: Tricuspid Regurgitation Following Conduction System Pacing Lead Entanglement in Chordae Tendineae

Case Description: A 62-year-old male with symptomatic sinus bradycardia presented for pacemaker implantation. Conduction system pacing (CSP) was pursued using the Medtronic 3830 lead. The lead was advanced through a C315His sheath and positioned at the basal-mid ventricular septum. Passive pacing demonstrated V1 notching and aVR/aVL discordance. An attempt was made to fixate the lead but despite rapid clockwise turns at the proximal lead tip, no lead penetration was seen in the LAO projection. The lead was removed and the sheath was repositioned. A second attempt was made with similar results. When attempting to remove the lead however, the lead remained adherent to the tissue despite multiple counter-clockwise turns. Increasing traction was applied at the proximal lead tip which resulted in elongation of the fixation screw and eventual disengagement from the tissue. Upon examination of the lead tip, there was fibrinous tissue suggestive of either chordae tendineae or valve remnant. Further attempts at CSP were aborted and the patient underwent traditional RV septal lead placement. Transthoracic echocardiogram (TTE) performed following the procedure demonstrated mild-moderate eccentric tricuspid regurgitation, likely due to chordae injury. Discussion: Left bundle branch pacing (LBBP) is becoming an increasingly popular form of CSP and requires deep penetration of the septum to engage the left bundle branch. To our knowledge, this is only the second case describing tricuspid valve chordae tendineae entanglement as a result of a CSP attempt. Most often, tricuspid regurgitation due to LBBP is attributed to entrapment of the septal TV leaflet from a basal position of the pacing lead. In our case, we suspect tricuspid valve injury occurred as a direct result of entanglement of the screw into the chordae. Potential ways to mitigate this complication are to pursue a more distal implantation site or to confirm adequate passive injury current prior to fixation to ensure the screw tip engages the myocardial tissue. Most of all, it is important to recognize that when a lead is not advancing into the septum, one should abort the position early and try an alternative site to avoid complications.

Abstract 14140: Management and Outcomes of Bacteremia After Transvenous Lead Extraction Complicated by Retained Lead Fragments

Introduction: Complete hardware removal is indicated for cardiovascular implanted electronic devices (CIED) infection. While transvenous lead extraction (TLE) is often successful in removing the entire device, some patients are left with residual hardware due to lead breakdown or unsuccessful attempts at removal. We sought to assess the outcomes and management in patients with retained CIED components that can be a nidus for ongoing infection. Methods: Single center retrospective case series among patients with lead extraction between 2010 and 2022. Results: There were 9 of 930 TLE patients (1%) who met study criteria (age 68 ± 23 yrs, 78% men, 67% ICD, 44% CRT, oldest lead 10.1 yrs IQR 6.1-22.2, combined lead age 21.2 yrs IQR 14.7-54.9). Two patients (22%) had epicardial leads as well. The majority of patients (n=8/9, 89%) had systemic infection, including lead vegetations in 22% (n=2). The most common infection organism was Staphylococcus aureus (n=5, 56%). Residual CIED components included lead tips (n=4, 44%), epicardial leads (n=2, 22%), entire intravascular lead portion (n=2, 22%), and a remnant ICD coil remaining in the SVC (n=1, 11%). TLE attempt was halted in 1 patient with a right atrial perforation during extraction (only removed 4/6 leads) and another patient with unsuccessful removal via laser, mechanical, and snaring attempts. Device reimplantation was performed in 4 patients (44%). The patient with the RA perforation underwent reimplantation of an epicardial system at the time of repair. Median follow-up was 0.9 years (IQR 0.4-7.2). Three patients (33%) were managed with indefinite antibiotic suppression, while the median antibiotic duration for the remainder was 35 days (IQR 14-43). Two patients (22%) had recurrent infections, both of which occurred despite the use of indefinite antibiotic suppression. None of the patients with residual lead tip alone had subsequent infections or were managed with suppressive antibiotics. Conclusion: Recurrent infection can be problematic when retained lead components are present after TLE and occurred despite the use of indefinite suppressive antibiotics in some patients. Further investigation is necessary to determine if the risk of recurrent infection varies by the type of residual CIED components.

Transient loss of atrial capture: the "atrial pacemaker stunning" phenomenon.

Atrial loss of capture in the chronic phase after implantation may be permanent due to various causes, e.g. technical lead problems or increased scar tissue formation around the lead tip. However, it may also be transient after atrial ischemia in the context of occlusion of the right coronary artery. In this case, it may be preferable to wait for recovery, which may take up to 45days, instead of immediately performing an atrial lead revision.

Respiratory Sensing Lead Malfunction in Upper Airway Stimulation: A Single Institution Report.

Upper airway stimulation (UAS) is an effective treatment for patients with obstructive sleep apnea. The device consists of a stimulating electrode, an internal pulse generator, and a respiratory sensing lead. The purpose of this study is to characterize the incidence of sensing lead malfunction necessitating revision surgery in a high-volume center in conjunction with a review of the FDA Manufacturer and User Facility Device Experience (MAUDE) database reports on adverse events associated with the sensing lead component. Patients age ≥18 implanted with the device were reviewed between July 2017 and June 2022. Those determined to have sensing lead malfunction were analyzed. The FDA MAUDE database was reviewed for reports associated with "Inspire Model 4323 Respiratory" and "Inspire Model 4340 Respiratory" between January 2014 and September 2022. One hundred ninety patients underwent UAS at our institution during the study period and four (2.1%) patients were found to have sensing lead malfunction. Analysis of the MAUDE database revealed 122 reports of adverse events associated with the sensing lead component, with 72% (88/122) of these requiring revision surgery. The most frequently reported adverse event was sensing lead tip separation from lead body, noted in 46% of these reports (56/122). The functionality of the sensing lead component is vital to the integrity of the UAS device and is measurable through waveform analysis. To provide optimal care after device implantation, it is essential to have a comprehensive understanding of the scenarios in which this component fails, the incidence of such events, and appropriate management. 4 Laryngoscope, 134:1479-1484, 2024.