Lead Implantation Research Articles

Stylet-driven vs. non-stylet-driven lead implantation for left bundle branch area pacing

Abstract Funding Acknowledgements Type of funding sources: None. Background Left bundle branch area pacing (LBBAP) is a novel pacing strategy, which overcomes limitations of right ventricular pacing. Conventional stylet-driven and non-stylet-driven leads have been used as a conduction system pacing lead. Procedural outcome data comparing both lead types are, however, scarce. Purpose To compare procedural outcomes during CSP device implantation with respect to the use of stylet-driven vs. non-stylet-driven leads. Methods We prospectively assessed 170 consecutive LBBAP lead implantation attempts at our center from 09/2021 to 11/2022. All implanters had previous experience with His-bundle pacing lead implantation using the non-stylet-driven lead and 91% of all systems were implanted by two high-volume device implanters. Successful conduction system pacing was established according to standard criteria (LBBAP: R-wave peak time in V6, V1-V6-interpeak interval, programmed stimulation or visibility of a left bundle potential) and pacing thresholds (<2V/0.5ms). The used leads in this analysis were the non-stylet-driven 3830 SelectSure lead (Medtronic, US) and the stylet-driven Solia (Biotronik, Germany), Ingevity+ (Boston Scientific, US) and Tendril STS (Abbott, US) lead. Patient selection and implantation strategy was at the operator’s discretion. Results Clinical baseline characteristics, echocardiography/ECG data and indications did not differ between patients, who received a stylet-driven or non-stylet-driven lead (table showing percentages and median values/interquartile ranges). Patients underwent implantation of a non-stylet driven 3830 SelectSure lead in 20% of cases and a stylet-driven lead in 80% of cases (Solia 76%, Ingevity+ 3%, Tendril STS 1%). Electrical outcome data did not differ between lead types. However, procedural success rate was significantly higher using stylet-driven leads (p=0.025) and a trend towards shorter overall intervention duration was observed as well (p=0.1). Conclusion Stylet-driven leads offer higher LBBAP lead implantation success rates while shortening implant duration.

Conduction system pacing guided by 3d-electroanatomic mapping system preserves systolic function in paediatric patients

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction Paediatric transvenous permanent pacing from alternative ventricular sites including conduction system pacing may prevent ventricular dyssynchrony and systolic dysfunction. These procedures may be difficult and require higher fluoroscopic exposures. The use of three-dimensional-electroanatomic mapping system (3D-EAM) may guide lead implantation toward these alternative sites and reduce fluoroscopic exposure. Purpose of this study is the outcome of 3D-EAM-guided alternative sites pacing in paediatric patients. Methods Retrospective analysis of children and young patients with congenital or acquired complete atrioventricular block (CAVB) with or without other congenital heart disease (CHD) who underwent 3D-EAM-guided transvenous pacing in alternative sites of the subpulmonary ventricle, to perform non-selective His bundle pacing (NSHBP), pacing of ventricular septum close to conduction system (VS-CSP) or outflow tract (OT). 3D-pacing map guided stylet-directed screw-in lead implantation toward septal sites with narrower paced QRS. Procedure and follow-up data were recorded. Parameters of ECG (QRS duration, left ventricular activation time, LVAT), echocardiogram (3D ejection fraction, EF, global longitudinal strain, GLS, of the systemic ventricle) and lead (threshold, sensing) were registered and compared at baseline (pre-implantation) and during follow-up (1-3-year). Data are reported as median (25th-75th centiles). P<0.05 was significant. Results 64 patients (47 females) with CAVB, of whom 11 with CHD, underwent 3D EAM-guided pacing (31 VVIR, 33 DDD) at age 12 (8-15) years, weight 44 (27-57) kg. Prior pacing (RV apex, RV and LV free wall, also biventricular) was present in 27 patients. Pacing sites were: 10 NSHBP, 5 RVOT, 49 VS-CSP (Figure 1). Procedure time was 175 (146-200) min, fluoroscopy exposure was: 3.0 (1.2-5.0) mGy and 90 (33-146) microGy/m2. Echographic parameters at baseline and follow-up are reported in Table 1. Baseline QRS duration 85 (80-130) ms, increased after implantation, 115 (100-120) ms (P=0.002), with LVAT 80 (70-81) ms (Figure 1). In patients with prior pacing, QRS shortened post-implantation: QRS 130 (120-160) vs. 120 (110-125)ms (P=0.004). Lead parameters were good post-implantation and at 3-year follow-up: threshold 0.5 (0.4-0.7) vs. 0.9 (0.7-1.2)V/0.5 ms; R-wave sensing 9 (6-12) vs. 7 (4-9)mV. Four NSHBP patients showed lead dislodgement requiring lead repositioning. Conclusions 3D-EAM-guided alternative site pacing was accomplished with low fluoroscopic exposure. Paced QRS duration was significantly broader than in junctional rhythm but it was significantly narrower than prior epi/conventional site endo pacing. This pacing approach preserved ventricular systolic function in paediatric patients with CAVB at mid-term follow-up.

Zero or near-zero x-ray pacemaker implantation in paediatric patients. dream or reality?

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction Transvenous implantation of pacemaker is performed with fluoroscopy for leads’ insertion and implantation in the heart. This implies radiation exposure for patients and operators. Fluoroscopy allows a two-dimensional view of lead movements, and sometimes it is difficult to implant lead in the complex heart anatomy, or in alternative right ventricular (RV) pacing sites, that often requires higher radiation doses. These alternative pacing sites may prevent pacing-induced ventricular dysfunction. They are his bundle pacing area (HBP), ventricular septum close to the conduction system area (VS), RV outflow tract (RVOT). The use of three-dimensional-electroanatomic mapping system (3D-EAM) may reduce fluoroscopy and guide lead implantation. Published median fluoroscopy data for similar procedure are: 6 mGy (1), 13 mGy and 231 microGy/m2 (2). Purpose of this study is to seek out if a 3D-EAM-guided transvenous implantation into RV alternative sites pacing in paediatric patients can be accomplished with zero or near-zero X-rays. Methods Retrospective analysis of children and adolescents with congenital or acquired (idiopathic) complete atrioventricular block (CAVB) without other congenital heart defects who underwent 3D-EAM-guided pacing in alternative RV sites. The implant procedure was divided in 4 steps: 1-contrast venography; 2- 3D mapping: with a steerable catheter (femoral vein), the 3D-EAM acquired geometric reconstruction of the right heart and a pacing map identified RV sites with narrower paced QRS; 3-axillary vein puncture; 4-lead and pacemaker implantation: 3D-EAM guided stylet-directed screw-in lead implantation toward desired RV sites. Data are reported as median (25th-75th centiles). Results 54 CAVB patients (42 females), underwent 3D EAM-guided pacing (27 VVIR, 27 DDD) at age 11.5 (7.7-14) years, weight 42 (26-54) kg. Pacing sites were: 10 HBP, 4 RVOT, 40 VS (Figure 1). Procedure time was 170 (143-193) min, total fluoroscopy exposure and that of the 4 steps are reported in Table 1. The lowest exposures were: 0.2 mGy, 8 microGy/m2 (VVIR) and 0.6 mGy, 15 microGy/m2 (DDD). Paced QRS was 115 (100-120) ms. Conclusions 3D-EAM-guided alternative RV pacing sites was accomplished with very low fluoroscopic exposure, close to zero in some cases. Therefore, with 3D-EAM we can significantly reduce radiological doses also in difficult pacing procedures in paediatric patients, thus reducing radiological risks and preserving ventricular function. The dream is becoming reality.

Left bundle branch area pacing guided by electroanatomical mapping in patients with structural heart disease and advanced conduction abnormalities

Abstract Funding Acknowledgements Type of funding sources: None. Background Left bundle branch area pacing (LBBAP) can be technically challenging and fluoroscopy-intense, particularly in patients with structural heart disease (SHD) and advanced conduction abnormalities. Three-dimensional electroanatomical mapping (EAM) facilitates high-resolution, real-time, and non-fluoroscopic lead navigation, electrogram and pace mapping. Purpose The purpose of the study was to prospectively evaluate the feasibility, safety, and outcomes of routine EAM-guided LBBAP in patients with SHD and advanced conduction abnormalities. Methods Consecutive patients with SHD and advanced conduction abnormalities (defined as second or third-degree atrioventricular (AV) block and/or complete bundle branch block) who underwent an attempt at EAM-guided LBBAP were included. EAM-guided lead implantation was performed in all patients following a standardized protocol irrespective of the pacing indication and type of conduction disturbance. The feasibility, safety, procedural and mid-term outcomes were evaluated. Electrical, echocardiographic, and clinical parameters were assessed at implantation and last follow-up. Results Thirty-two patients (68±18 years; 19% female) were included. The indication for pacing was cardiac resynchronization therapy in 50%, AV block in 44%, and pace-and-ablate in 6% of patients; 24 patients (75%) had an intrinsic QRS >150 ms, 17 (53%) had LBBB. Primary EAM-guided LBBAP was successful in 29 patients (91%). Procedural duration was 95 (70-110) min, total fluoroscopy time 0.93 (0.40-1.73) min, and total fluoroscopy dose 35.4 (20.5-77.2) cGycm2 (Figure 1A). The paced QRS duration during LBBAP was significantly shorter than the baseline intrinsic QRS duration (121.9±10.7 vs. 159.2±34.4 ms; p<0.001) (Figure 1B) and remained stable (120.3±11.1 ms; p=0.370) during a mean follow-up of 7.0±5.9 (median 5.4 [IQR 2.1-12.6]) months. LBBAP capture threshold was 0.57±0.23V/0.4ms at implantation and remained low during follow-up (0.58±0.18V/0.5±0.2ms; p=0.877). There was no increase in LBBAP capture threshold >1.0V/0.4 ms during follow-up. Overall LVEF improved significantly from 44.2±14.3% at baseline to 49.4±13.1% at last follow-up (p=0.009), NYHA functional class from 2.4±0.6 to 1.8±0.6 (p=0.002), respectively (Figure 1C+D). No complications occurred that required intervention. Conclusion Routine near-zero fluoroscopy EAM-guided LBBAP can safely be performed in patients with SHD and advanced conduction abnormalities with high success rates and favourable mid-term outcomes. Further studies are needed to investigate whether the use of EAM improves overall outcome of conduction system pacing, and to identify specific patient populations who benefit the most from EAM-guided lead implantation.

Axillary vein puncture versus cephalic vein cutdown for cardiac implantable electronic device implantation: a meta-analysis

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Cephalic vein cutdown (CVC) and axillary vein puncture (AVP) are both recommended for transvenous implantation of leads for cardiac implantable electronic devices (CIEDs). Nonetheless, it is still debated which of the two techniques has a better safety and efficacy profile. Methods We systematically searched Medline, Embase and Cochrane electronic databases up to September 5th, 2022, for studies that evaluated the efficacy and safety of AVP and CVC reporting at least one clinical outcome of interest. The primary endpoint was acute procedural success. The effect size was estimated using a random-effect model as Risk Ratio (RR) and relative 95% Confidence Interval (CI). Results Overall, 8 studies were included, which enrolled 1926 patients and 3532 transvenous lead implants [66.3% (n=1277) males with an average age of 72.3±14.8 years]. Compared to CVC, AVP showed a significant increase in the primary endpoint (95.7 % vs 76.1 %; RR: 1.24; 95% CI: 1.09-1.40; p=0.001) (Figure 1). Total procedural time (Mean Difference [MD]: -8.25 min; 95%CI: -10.23- -6.27; p<0.0001; I2 =0%) and venous access time (MD: -6.24 min; 95%CI: -7.01- -5.47; p<0.0001; I2 =0%) were significantly shorter with AVP compared to CVC. No differences were found between AVP and CVC for incidence of pneumothorax (RR: 0.72; 95% CI: 0.13 - 4.0; p=0.71), lead failure (RR: 0.58; 95% CI: 0.23-1.48; p=0.26), pocket hematoma/bleeding (RR: 0.58; 95% CI: 0.15- 2.23; p=0.43), device infection (RR: 0.95; 95% CI: 0.14- 6.60; p=0.96) and fluoroscopy time (MD: -0.24 min; 95%CI: -0.75- 0.28; p=0.36). Conclusion Our meta-analysis suggests that AVP may improve procedural success and reduce total procedural time and venous access time compared to CVC.

Defibrillation testing during S-ICD implantation: How relevant? Results from a multicenter study

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Defibrillation testing (DFT) is still recommended in patients with subcutaneous implantable cardioverter-defibrillator (S-ICD) to ensure proper detection of ventricular fibrillation and confirm effective defibrillation. Given the significant risk of complications, recent studies, are reconsidering the interest of the DFT in S-ICD. The purpose of this study was to assess the clinical "real-life" outcomes of DFT over a mid-term follow-up period after third-generation S-ICD implantation. Methods and Results 368 patients (pts) (47.9 ± 15.5 years old; male 72.8%) implanted with Generation 3 S-ICD system were included in this retrospective multicenter registry-based study. Mean left ventricular ejection fraction (LVEF) was 40.8% (primary prevention 56.1%). For 99.2% pts, S-ICD implantation was performed using the two-incision technique and intermuscular positioning of the generator was performed for all pts. 81% pts underwent ICD testing during implantation. Reasons for not performing DFT were: very low LVEF (3.5%), intracardiac thrombus (2.4%) and VF induction failure. In 2.2% (8 pts) DFT was unsuccessful, causes were: induction of ventricular tachycardias with rates falling below the shock zone for 3 pts while shocks were ineffective for 5 pts. One patient required revision for contralateral lead implantation, while sensing vector reprogramming and shock polarity modification were efficient for the others. The mean impedance was 68.4 (±14.7) Ω and time to shock therapy ranged from 10 to 33 s, with a mean of 16.7 (±4) s. A total of 36 appropriate shocks (10.1%) have been observed after a FU period of 11.02±8.8 months (1.8 shocks per patient, several shocks for 12pts, failure of the first shock for 5 patients). 17 patients (4.6%) underwent S-ICD system extraction. The reasons were pocket site complication (7 pts), pacing indication for cardiac resynchronization therapy or bradycardia (3 pts), and S-ICD lead dysfunction (4 pts). Extraction after heart transplant was needed in 3 pts. Among the 4 pts explanted for system dysfunction, only one patient had a DFT during implantation. After a mean follow-up of 19±12.1 months, the mortality rate was 3.8% (no S-ICD-related deaths were reported). There was no significant difference between the 2 groups of pts with and without DFT testing (p=0.629). Conclusion The DFT remains for the moment highly recommended during S-ICD implantations. Results from randomized studies are still needed to confirm the relevance of DFT during S-ICD implantation.

The last shall be the first: the role of combined QLV- and CMR-determined electromechanical concordance in predicting optimal left ventricular stimulation site in cardiac resynchronisation therapy

Abstract Funding Acknowledgements Type of funding sources: None. Background/introduction Optimisation of cardiac resynchronisation therapy (CRT) response still represents a significant challenge to cardiac electrophysiology. In this regard, perhaps the area of greatest uncertainty revolves around optimal left ventricular lead (LVL) position and in particular whether this should be directed at areas of latest electrical or mechanical activation given the equivocal evidence on their precise relationship in heart failure (HF) patients. Furthermore, while echocardiography has demonstrated that LVL aimed at regions of greatest mechanical delay maximises CRT response, cardiac magnetic resonance (CMR) with its greater spatial resolution and tissue definition is yet to demonstrate a role in doing so. Purpose To retrospectively evaluate concordance between latest electrical and CMR-determined mechanical activation in a CRT population and its relationship with reverse remodeling. Methods This is a retrospective single center analysis of 104 CRT patients. All patients had CMR and echocardiography performed before implantation. During implantation, coronary sinus angiogram was performed and electrical delay (QLV time with RV-LV time greater than 80 ms) was mapped on all veins suitable for lead implantation and LVL was positioned in the region of latest electrical activation programming LVL cathode accordingly. LVL cathode position was thus assumed to represent the region of latest electrical delay. A post-hoc analysis was then conducted by means of CART-Tech® software providing radial strain and scar maps on a 36-segment anatomical model. Patients were then stratified based on concordance between LVL cathode position (using 3D heart models superimposed on 2D angiography images) and most mechanically delayed segments (either the three most delayed segments or adjacent ones) or non concordance (one or more segments between LVL cathode and three most mechanically delayed segments). Data from patient follow-up was collected with echocardiography at least 3 months after implant date. CRT response was expressed as reduction in end-systolic volume (ESV) greater than 15%. Results A preliminary analysis of the first 30 patients of our cohort was conducted. Electromechanical concordance and non-concordance were present in 24 and 6 patients, respectively. Baseline patient characteristics including demographics, comorbidities, HF aetiology, ECG and echocardiography features were comparable between groups except for scar burden, which was higher in the non-concordance group. Response to CRT was 80% in the concordant vs. 20% in the non-concordant group. Conclusions While a confounding effect of scar burden cannot be excluded, these preliminary data suggest that electromechanical concordance in LVL cathode placement may represent a predictor of optimal CRT response. The full scope of this study will be fully appreciated in the coming month on completion of analysis of the entire patient cohort.

Self-taught ultrasound-guided axillary vein access for pacemaker implantations - complication rates and outcomes

Abstract Funding Acknowledgements Type of funding sources: None. Background Cardiac implantable electronic devices (CIEDs) are the mainstream therapy for advanced atrioventricular block or sustained ventricular arrhythmia. EHRA survey (1) showed that cephalic vein dissection and blind subclavian vein puncture are the preferred techniques for the implantation of CIED leads in European centres. Ultrasound (US) guided axillary puncture has emerged as feasible alternative for safe and rapid venous access for lead implantation. However, insufficient evidence to support its widespread adoption. Aim To compare the complication rates and clinical outcomes of CIED implantations utilising self-taught US guided axillary puncture versus non-US guided venous access (Subclavian puncture and fluroscopy guided axillary puncture). Assess the mean time to gain venous access and overall success rate in US guided technique. Methods Retrospective , observational study across two sites involving all CIED implantations of four experienced implanters over the year from January 2021 - June 2022. Patient's demographics, venous access time, complications and clinical outcomes were extracted from electronic database. US axillary access technique was self-taught. Results and Outcomes Venous access was obtained by US Guided axillary puncture in 146 patients, non-US guided in 208 patients. Successful axillary venous access by ultrasound guidance is 97%(146/151) with mean time to venous access of 2.1 minutes. Baseline demographics (age, gender) and comorbidities (hypertension, diabetes, cardiomyopathy, coronary artery disease, dyslipidemia, renal failure, oral steroid use, nicotine use) were similar between both US-guide and non-US guided groups, usage of oral anticoagulations (32.9% vs 39.4%,p=0.208) and antiplatelet agents(28.1% vs 35.1%,p=0.164) were not statistically different. Greater proportion of dual chamber pacemakers were implanted in US guided access group versus non-US guided (39.7% vs 27.9%,p=0.015). US Guided axillary access resulted in lower overall complication rate (2.1% vs 8.9%, p=0.0196): lower risk of pneumothorax (0% vs 3.8%,p=0.0236), lower risk of haemathoma (0% vs 3.4%,p=0.0448). No difference in short term pocket/lead infection or lead displacement. Severe vascular complications remains low in both groups. Stepwise binary regression analysis demonstrated US guidance as independent predictor of lower overall complication rate, odd-ratio 0.195 (95% CI 0.054 - 0.706). Summary: This multi-centered, retospective observational study demonstrated that US guided axillary access has high overall success rate, not time consuming and resulted in lower complication rates (especially pneumothorax and pocket haemathoma), despite the US access technique being self-taught and have greater proportion of dual chamber device implantations. US guided axillary access is demonstrated to be independently associated with 5-fold lower risk of complications.

Percutaneous epicardial pacing in infants using direct visualization: A feasibility animal study.

Pacemaker implantation in infants and small children is limited to epicardial lead placement via open chest surgery. We propose a minimally invasive solution using a novel percutaneous access kit. To evaluate the acute safety and feasibility of a novel percutaneous pericardial access tool kit to implant pacemaker leads on the epicardium under direct visualization. A custom sheath with optical fiber lining the inside wall was built to provide intrathoracic illumination. A Veress needle inside the illumination sheath was inserted through a skin nick just to the left of the xiphoid process and angled toward the thorax. A needle containing a fiberscope within the lumen was inserted through the sheath and used to access the pericardium under direct visualization. A custom dilator and peel-away sheath with pre-tunneled fiberscope was passed over a guidewire into the pericardial space via modified Seldinger technique. A side-biting multipolar pacemaker lead was inserted through the sheath and affixed against the epicardium. Six piglets (weight 3.7-4.0 kg) had successful lead implantation. The pericardial space could be visualized and entered in all animals. Median time from skin nick to sheath access of the pericardium was 9.5 (interquartile range [IQR] 8-11) min. Median total procedure time was 16 (IQR 14-19) min. Median R wave sensing was 5.4 (IQR 4.0-7.3) mV. Median capture threshold was 2.1 (IQR 1.7-2.4) V at 0.4 ms and 1.3 (IQR 1.2-2.0) V at 1.0 ms. There were no complications. Percutaneous epicardial lead implantation under direct visualization was successful in six piglets of neonatal size and weight with clinically acceptable acute pacing parameters.

PO-01-025 EPICARDIAL LEAD PERFORMANCE TRENDS IN PEDIATRICS AND CONGENITAL HEART DISEASE: WHAT STARTS UP, MUST COME DOWN

Small children and certain types of congenital heart disease (CHD) require epicardial CIED systems when pacing is indicated. Lead performance at implant is potentially affected by patient clinical status, as many of these systems are placed during other operation for CHD or in the post-operative period. Anatomical alterations and scarring from prior procedures may result in limited options and higher lead performance measurements are often accepted at implant. To assess evolution of epicardial lead performance in the acute post-implant period at mid-term follow-up. Retrospective single center study of children and adult congenital heart disease patients undergoing epicardial bipolar pacing lead and generator implantation between 1/2012-6/2022. Patients were censored in follow-up at the time of lead removal, patient death, or pacing polarity change to unipolar. There were 256 leads implanted in 128 pts (mean age 6.1 ± 9.8 years), including 201 (79%) leads implanted in patients with CHD and 138 (54%) implanted in the perioperative or immediate post-operative period (within 30 days). Implant sites were: 76 right atrial, 71 right ventricle, 39 left atrial and 70 left ventricle. Threshold for measurements were available at 6 weeks and 1 year for 160 (63%) and 138 (54%) respectively. The mean threshold at time of implant was 1.3 (range 0.1-6) V. Mean threshold change from implant to post op day 1 (POD1), 6 weeks and 1 year was: –0.34±0.78V (p=0.0001), –0.23 ±0.85V (p=0.003), and –0.2±0.9V (p=0.0026), respectively. At implant, 47 leads (18%) had a threshold ≥ 2 V, of which 42/47 (90%) decreased to <2 by POD1. Leads with higher threshold at implant had a mean decrease in threshold by POD1 of -1.33 V vs. -0.44 V for leads with an implant threshold of <2V (p<0.0001). For patients with an implant threshold of ≥2V, impedance >1000 ohms, CHD, perioperative or acute post-op status, and location of the lead did not significantly impact the odds of having a persistently higher threshold (≥2 V) on POD1. Epicardial pacing lead thresholds improve significantly in the immediate post-op period, even when initial measures could be considered unacceptably high and remain stable at one year post implant. Most leads with high implant thresholds improved to <2 by POD1. No factors effecting the likelihood of improvement were identified. While striving for low threshold at implant remains important, these data support a high likelihood that thresholds will optimize by POD 1.

PO-03-077 CENTRAL VENOUS OCCLUSION IN PEDIATRIC PATIENTS WITH TRANSVENOUS DEVICE LEAD RE-IMPLANTATIONS

Central venous occlusion is a risk when using transvenous pacemaker leads, which may complicate repeated lead implantation. This is particularly important in young children with small body sizes, who often need an upgrade from single to dual chamber device later in life. Furthermore, lead survival is reported to be shorter in children compared to adults. Despite this, there are limited data on venous access patency during repeated lead implantations in patients receiving their first transvenous device during childhood. We aimed to assess the rate of central venous occlusion at repeated and third transvenous lead implantation in patients, who received their first transvenous device during childhood. All children who received a transvenous pacemaker or ICD before the age of 15 and had a repeat transvenous lead implantation were identified in the Danish National Pacemaker and ICD Registry. Patient and device characteristics were retrieved from medical charts. Between 1977 and 2021 284 children had a transvenous device implanted. Median age at first implantation was 7.4(IQR2.9-11.3) years. 139 patients underwent re-implantation of lead after median 7.7(IQR2.7-10.5) years. Most frequent causes of re-implantation were lead failure, lead fracture and growth-related lead problems. At first re-implantation, nine patients (6.5%) had venous occlusion of which three patients (2.2%) led to using the contralateral venous access. It was found that age below 7 years at first lead implantation predicted venous occlusion at first reimplantation(P-value 0.04). Median age at second lead re-implantation was 18.1(IQR 13.2-22.5) years. Median time between first and second lead re-implantation was 4.6(IQR 1.4-7.0) years. At second re-implantation, seven patients (5.0%) had venous occlusion. Repeatedly, age below 7 years was a risk factor of venous occlusion (P-value 0.02). In pediatric patients with repeated transvenous lead implantation, 6.5% had a venous occlusion at first re-implantation and 5.0% at second reimplantation. Age below 7 years was found to be a risk factor of venous occlusion at both first and second re-implantation. To increase transvenous patency in children with life-time device need, transvenous lead implantation should be avoided at age below 7 years.

PO-04-013 A CASE OF INTERMITTENT ANODAL CAPTURE AFTER LEFT BUNDLE AREA PACING

Left bundle area pacing (LBAP) is emerging as a reliable form of conduction system pacing (CSP) that can be beneficial in cardiac resynchronization therapy (CRT). We present a case of intermittent anodal capture noted after septal lead insertion in a patient undergoing LBAP. N/A An 80-year-old male with hypertension, COPD, and sick sinus syndrome who had undergone dual chamber pacemaker implantation in 2007, had known atrial lead fracture since 2020, now presented with heart failure syndrome (EF dropped from 60% to 15%). A coronary angiogram showed non-obstructive coronary artery disease. As such decision was made for fractured atrial lead extraction and implantation of new atrial lead to provide AV synchrony as well as upgrading the device to biventricular ICD, given the persistent low ejection fraction. During the procedure, coronary sinus anatomy was found unsuitable for lead insertion, and hence LBAP was opted for instead. LBAP lead was placed at an appropriate septal location with QRS morphology in lead V1 changing from an initial “W” pattern to notching as the lead was advanced with an appropriate rise in thresholds. QRS duration decreased to 144 milliseconds; however, intermittently variable QRS morphologies were noted. In LBAP, anodal capture can occur during bipolar configuration where the tip of the lead (cathode) is capturing the left bundle, and the ring (anode) starts capturing the right bundle area. This happens when the lead is penetrating the interventricular septum (IVS) enough for the ring portion to come into contact with the right septal area. In our patient, note the different QRS morphologies in lead V1 (Panel A). The right bundle morphology QRS (marked red) is the expected result of LB pacing, while the left bundle morphology QRS (marked green) is likely occurring from concurrent anodal capture of the right bundle. The QRS duration is noted to be somewhat narrower when the left bundle morphology is present, as would be expected when both bundles are simultaneously captured (LB by the tip and RB by the ring) (Panel B). It is unclear whether such a phenomenon as anodal capture of the RB along with concurrent LB pacing can be of any clinical significance and needs further research.

PO-05-047 METHODOLOGY OF VENTRICULAR SEPTAL PACING USING STYLET-DRIVEN LEAD AND THREE-DIMENSIONAL GUIDING CATHETER

Superiority of conduction system pacing is recognized and need for septal/physiological pacing is emerging. Recently, catheter-guided implantation of stylet-driven lead(SDL) was introduced to clinical use. The present study was carried out to investigate the acute efficacy and safety of different strategies of catheter-guided ventricular septal implantations of SDL compared to apical implantation. We retrospectively analyzed consecutive patients who underwent implantation of ventricular leads, including both apical implantations and initial experience of septal implantations. The paced QRS duration was compared between 4 groups: G1(apical implantation), G2(septal with fluoroscopic guidance), G3(septal with echo-guidance), G4(septal with echo-guidance and additional lead-body rotation). Body rotation was performed to purpose deep septal pacing. We also performed multivariate analysis to find predictors of short QRS duration less than 130ms during ventricular pacing. In total, 80 patients were analyzed. Selectra3D catheter was exclusively used to implant conventional screw-in leads into septum. Eight physicians (6 in-training and 2 experienced) implanted all the ventricular leads. The number of patients in G1,G2,G3,and G4 were 21,12,29,and 19, respectively. In-procedural or post-procedural dislodgement of septal lead was less frequently in G3/G4 compared to G2(2% vs. 21%). The QRS duration were 161±15,146±13,140±11,and 132±18ms, respectively.(Figure) As for echo-guided implantation cohorts (G2 and G3), multivariate analysis revealed body-rotation(OR: 5.72(95%CI: 1.46-22.4), P=0.012) and experienced physician (OR:5.48(95%CI: 1.16-25.8), P=0.031) were significantly associated with short QRS duration. Combination of echocardiographic guidance and body-rotation could be effective to improve procedural and clinical results after catheter-guided septal implantation of SDLs.

PO-04-104 MANAGEMENT OF FROZEN PACEMAKER LEADS IN GENERATOR EXCHANGE

As the number of cardiac implantable electronic devices (CIEDs) increases, so does the need for generator exchanges. While rare, chronic pacemaker leads may become frozen in the header or may fracture when removal is attempted. This can lead to unnecessary lead implants and extractions if the lead is damaged while removal is attempted. We present a case and discuss our technique to safely remove these leads without damage to the lead itself during generator exchange. To highlight a technique to manage frozen pacemaker leads during generator exchange. N/A An 89 year old lady presented for elective generator exchange for elective replacement indicator. The leads were 31 years old (Intermedics Pacemakers Inc, Tx). When attempting to unscrew the right ventricular lead, Intermedics model 430-02, the pin became partially separated from the rest of the lead. Thus, the lead was pushed back into the header and a sterile saw was used to remove the header from the tip of the lead. We utilized two surgical clamps to create a guide so the saw stayed in the desired direction. Once the back of the header was cut out, the torque wrench was used to push the pin through intact. Though rare, the increasing number of CIED implants and generator exchanges makes encountering a frozen lead more likely in one’s career and successful management is imperative for patient outcomes, safety, and cost effectiveness. There have been rare reports of similar techniques using a variety of instruments, such as scalpels, drills, and bone cutters, to accomplish a similar effect. We have found a sterile saw to be the most effective way to manage these lead complications safely and effectively.

PO-01-048 FACTORS INFLUENCING SUBCUTANEOUS IMPLANTABLE CARDIOVERTER DEFIBRILLATOR SCREENING SUCCESS IN PAEDIATRIC POPULATION: A TERTIARY HOSPITAL EXPERIENCE

Implantable cardioverter defibrillators (ICD), used to reduce risk from life threatening ventricular arrhythmia, are important treatments. Subcutaneous ICD (SICD) offers a lower risk of endocarditis, lead fracture and vascular complication. Screening is essential to identify the appropriate candidates and reduce inappropriate shocks, however there are limited data available in the paediatric population. To assess the incidence and associated characteristics of SICD screen failure, and the incidence of inappropriate shocks in a paediatric population. All patients screened for SICD from June 2016 to November 2022 were included. Screening failures were identified from supine, standing and exercise in both left and right sternal positions. Those who passed at least two vectors in all conditions were offered an SICD. The incidence of inappropriate shocks on follow up was assessed. From 74 screened patients (baseline characteristics Table 1), 58 (78%) passed supine and standing and 51(69%) on exercise screening. 59 (67%) had Hypertrophic Cardiomyopathy (HCM), 17 (23%) Inherited arrhythmias (IA) and 8 (11%) Other Cardiomyopathies (OC). Overall, 60(81%) had a primary prevention indication. Of the 45 (61%) who passed screening on the left supine, all passed when standing and 43 (96%) passed on exercise. Those screened on the right, 18 (55%) passed supine, 16(88%) of these passed standing and 14(87%) passed on exercise. Those that failed were younger and had HCM (passed vs failed, age 14±2.6 vs 12±3.7, p=0.009, HCM 56% vs 87%, p=0.008). IA patients were more likely to pass (pass vs failed, 35% vs 8%, p=0.02). Weight, height and BMI did not impact on the failure rate (Table 1). Overall, 40 (78%) had an SICD implanted with a mean follow up 21±15 months. Four patients had inappropriate shocks; One for air in the header and three for T wave oversensing. Those who had T wave oversensing had left sided lead implants, two had HCM and one had AI. In this population the screen failure rate for SICD was high, particularly in younger patients with HCM. The addition of exercise further excluded patients however, the number was small. There was no link between weight, height and BMI and screen failure. The incidence of inappropriate shocks was low.Tabled 1Table 1 – Characteristics of patients who passed and failed Subcutaneous Internal Cardioverter Defibrillator ScreeningCharacteristicsPassed (n=51)Failed (n=23)p-valueAge, years mean (SD)14 ± 2.612 ±3.7p=0.009Sex F(%)17 (34)6 (26)p=0.6Weight kg, mean (SD)57 ±16.953 ±(22)p=0.34Height cm mean (SD)156 ±29.6155 ±17.8p=0.88BMI kg/m2 mean (SD)23 ± 10.421 ± 5.5p=0.39HCM n (%)29 (56)20 (87)p=0.008Inherited n (%)15 (29)2 (8)p=0.02Other Cardiomyopathy n (%)7 (14)1 (4)p=0.26 Open table in a new tab

Actual conditions of atrial septal lead implantation and the factors related to successful implantation

BackgroundPacemaker leads were originally implanted into the right atrial appendage (RAA) and right ventricular apex, but septal pacing, which is more physiological, is becoming increasingly popular. The usefulness of atrial lead implantation in the RAA or atrial septum is inconclusive, and whether or not atrial septum implantation is accurate has not yet been verified. MethodsPatients who underwent pacemaker implantation between January 2016 and December 2020 were included. The success rate of atrial septal implantation was validated using thoracic computed tomography performed for any reason postoperatively. We examined factors related to the successful implantation of the atrial lead in the atrial septum. ResultsForty-eight people were included in this study. Lead placement was performed with a delivery catheter system (SelectSecure MRI SureScan; Medtronic Japan Co., Ltd., Tokyo, Japan) in 29 cases and a conventional stylet in 19 cases. The mean age was 74 ± 12 years old, and 28 (58%) were male. Successful atrial septal implantation was performed in 26 patients (54%), with only 4 (21%) successful implantations in the stylet group. There were no significant differences in the age, gender, body mass index (BMI), pacing P wave axis, duration, or amplitude between the atrial septal implantation group and non-septal groups. The only significant difference was for delivery catheter use [22 (85%) vs. 7 (32%), p < 0.001]. In multivariate logistic analysis, the use of a delivery catheter was independently associated with successful septal implantation [odds ratio (OR): 16.9, 95% confidence interval 3.0–90.9] after adjusting for the age, gender, and BMI. ConclusionThe success rate of atrial septal implantation was very low at 54%, and only the use of a delivery catheter was associated with successful septal implantation. However, even with a delivery catheter, the success rate was 76%, so further investigations are warranted.

High predictive value of paced QRS frequency in verification of left bundle branch pacing.

Left bundle branch area pacing (LBBAP) is a newer technique to deliver more synchronous left ventricular activation. Several criteria have been proposed, but not fully validated, to confirm LBBAP during implantation of the pacing lead. Spectral analysis has been used to characterize the frequency components of the clinical QRS utilizing the Fourier transform algorithm. We hypothesized that higher frequency content of the paced QRS complex may show predictive value of successful LBBAP. We evaluated 84 patients with ejection fraction > 50%, who underwent LBB lead placement (n = 42) using ≥ 1 current criteria and right ventricular midseptal (RVsp) lead placement (n = 42) from 2000 to 2022. Time frequency analysis (Matlab) was used to determine the frequency content of the paced QRS complex. The centroid frequency (CF), which is the weighted average QRS frequency, was calculated. Patients in RVsp group had a longer paced QRS duration (155.6 ± 28.0 vs 127.1 ± 17.2, p < 0.002) compared to the LBBAP group. Of all standard ECG leads, the paced QRS in V2 gave the greatest difference of the CF of the LBBAP group at 8.8 ± 1.6 Hz versus 5.7 ± 0.7 Hz of the RVsp group. This difference was significant by both univariate (p < 0.003) and multivariate (p < 0.010) analysis. Predictive value of the CF for successful LBB pacing in lead V2 was highest with an AUC of 0.98. The sensitivity and specificity were 88.1% and 97.6%, respectively. Spectral analysis predicts successful LBBAP with higher frequency content when compared to RVsp pacing. Given the limitations to the current criteria to confirm LBBAP, intraprocedural use of frequency content analysis of the paced QRS complex in patients may prove useful at verifying LBB capture if verified by prospective clinical trials.

207 An Investigation Into the Characteristics of Peri-Lead Edema After Deep Brain Stimulation Surgery

INTRODUCTION: Peri-lead edema (PLE) is an increasingly recognized effect of deep brain stimulation (DBS) surgery. Despite this, PLE remains poorly characterized, with reports of the phenomenon’s incidence and clinical meaning differing widely among studies. METHODS: We regularly obtained 2 CT scans at each stage of routine DBS surgery (lead implantation and implantable pulse generator implantation) in 55 consecutive patients. Both image sets (early and late postoperative CTs) were inspected for PLE, and edema volume was manually segmented. Clinical characteristics were procured by chart review. Edema volume was assessed quantitatively and compared with clinical postoperative course to investigate any possible correlations. RESULTS: Zero (0%) and 24 (43.6%) patients were found to have PLE at stage one and stage two imaging, respectively. Nineteen of the edema patients were treated for Parkinson’s Disease and 5 for essential tremor. DBS targets were STN (12), VIM (6), and GPi (6). Mean edema volume was 8.10 ± 5.66 mL, with a median of 8.91 mL and ranging from 1.60 to 26.90 mL. Closer inspection of volume into left- and right-hemispheric PLE ascertained no discernible difference between each or to the total (ANOVA F &lt; 0.0005, p = 0.99), nor did an analogous partition into volume by target (ANOVA F = 0.19, p = 0.90). Three patients experienced symptomatic PLE, all of whom had DBS targeting VIM. One patient had experienced seizure, another with altered mental status and gait instability, and the last had dizziness and weakness. All fully recovered following antiepileptic medication for the patient with seizure, and the other two following steroid administration. CONCLUSIONS: PLE occurs in about half of the patients undergoing DBS and is usually asymptomatic. Symptomatic PLE may be managed to resolution in an outpatient setting with steroid administration.

504 Safety and Efficacy of Brain-Responsive Neurostimulation Treatment With Depth Leads Placed in the Neocortex

INTRODUCTION: Responsive neurostimulation (RNS) is efficacious in treating medically refractory epilepsy arising from neocortical foci. During clinical trials, most patients with neocortical seizure foci received cortical strip leads, perhaps due to intracranial monitoring with subdural grids/strips. Stereo-electroencephalography (sEEG) has become more widely utilized since the trials, resulting in increased placement of neocortical RNS depth leads. This is also an appealing approach when dural adhesions make strip lead implantation difficult. METHODS: We conducted retrospective chart review of adult patients with refractory epilepsy at seven institutions who underwent placement and connection of at least one RNS depth lead in the neocortex. RESULTS: 61 neocortical depth leads were connected to the RNS neurostimulator in 53 patients. 33 patients had additional depth leads in a non-neocortical focus, and 12 had an additional neocortical strip lead. Median follow-up was 2.2 years (range: 0.4 – 5.2 years). Median clinical seizure reduction in seizures was 63% at 1 y and 75% at last follow-up. 12 patients (23%) were seizure-free at last follow-up; a majority of these (83%) were seizure-free for &gt;6 mo, with five patients seizure-free for &gt;1 y. There were two (3.8%) scalp infections. One patient (1.9%) had each of the following: chemical meningitis, epidural hematoma, post-surgical status epilepticus (resolved with stimulation), new-onset non-epileptic seizures, and stimulation-related nausea (resolved with programming). CONCLUSIONS: Our multicenter series of 53 patients with neocortical-onset epilepsy treated with neocortical RNS depth leads demonstrated 75% median seizure reduction at 2 y of follow-up with a similar safety profile to placement of deep brain electrodes for movement disorders. Neocortical depth leads may be preferred with the RNS system following sEEG evaluation and/or if strip placement poses increased surgical risk.

Ultrasound-guided Axillary Vein Puncture for Cardiac Device Implantation: A Safe and Effective Approach

Ultrasound-guided axillary vein access is an effective alternative to conventional subclavian and cephalic access for cardiac implantable electronic device implantation. The aim of this study was to compare the safety, efficacy, and radiation exposure data of the ultrasound-guided axillary approach with other conventional access techniques. The study population included 130 consecutive patients, stratified as 65 (64% male; median age, 79 years) in the study group and 65 (66% male; median age, 81 years) in the control group. We performed a retrospective not-randomized analysis by comparing ultrasound-guided axillary vein puncture with subclavian and cephalic approaches in order to test the effect on X-ray exposure, total procedure time, and complications. Significant differences were observed in terms of radiation exposure, including fluoroscopy time (median, 95 s [study group] vs. 193 s [control group]; P < .001), air kerma (median, 29 mGy [study group] vs. 55.7 mGy [control group]; P < .001), and dose-area product (median, 8219 mGy·cm2 [study group] vs. 16736 mGy·cm2 [control group]; P < .001). The median procedure time was 45 min in the study group but 50 min in the control group (P < .05). Complications occurred in 6 control group patients (1 urticaria contrast medium-related, 3 pneumothorax, 2 subclavian artery puncture) and 2 study group patients (2 axillary artery puncture). We conclude that the ultrasound-guided axillary venous approach is a fast, feasible, and safe technique for cardiac lead implantation. It allows a significant reduction in fluoroscopy time without prolonging the procedural time. This approach offers direct visualization of the vessel during the puncture, so it can be useful in patients who cannot receive contrast medium, those who require "difficult" thoracic approaches (emphysema, too much or too little fat tissue), or those on anticoagulant therapy.