Lead Fracture Research Articles

Risk for appropriate ICD intervention and complications in patients implanted after an out-hospital cardiac arrest compared to patients implanted for primary and other secondary prevention indication

Abstract Background Few data are available about patients implanted with an implantable cardioverter defibrillators (ICDs) after an out-of-hospital cardiac arrest (OHCA). In particular, it is unclear if these patients have a higher risk of appropriate device therapy than patients implanted for primary and other secondary prevention. Purpose To assess if appropriate device interventions (ATP/shocks) are higher in patients implanted after OHCA compared to patients implanted for primary and secondary prevention other than OHCA. To verify also if mortality, implantation-related complications (pneumothorax, hemothorax, hematoma, cardiac tamponade), device-related complications (lead displacement and fracture, infections) and inappropriate shocks/ATP are higher in OHCA patients compared to other patients. Methods This is a retrospective multicenter international study. All the patients implanted with an ICD between January 2015 and December 2016 in the participating centers were included. Follow-up was considered concluded in case of death or at the last follow-up available until December 2023. Patients were divided according to ICD implantation indication (secondary prevention after OHCA, other secondary prevention, primary prevention). Results 1386 patients (79% males; median age 67, IQR 59-74) from 15 centers were included with a median follow-up of 83 months: 111 patients in OHCA group, 134 in other secondary prevention group and 1141 in primary prevention group. Considering the first appropriate intervention, a significant difference among the three groups was observed (Fig.1A) and, at post-hoc comparison, the OHCA group was at higher risk than primary prevention (HR 1.51, 95%CI 1.06-2.17, p=0.02), but was at similar risk than other secondary prevention (HR 0.79, 95%CI 0.51-1.23, p=0.3). This was confirmed also after correction for age, gender, history of atrial fibrillation, aetiology and multi-comorbidity (Fig.2A). However, considering the number of appropriate interventions during follow-up, the risk of OHCA group was lower than other secondary prevention (IRR 0.28, 95%CI 0.11-0.68, p<0.01) and similar to primary prevention (IRR 0.97, 95%CI 0.47-1.96, p=0.93), also after correction for the other predictors (Fig.2B). The three groups showed no differences in survival (Fig.1B), implantation-related complication, device-related complications (Fig.1C) and inappropriate shocks/ATP. Conclusion Patients implanted with an ICD after an OHCA have a risk similar to those implanted for other secondary prevention, when considering the first appropriate intervention, but a risk similar to those implanted for primary prevention when considering the number of appropriate interventions during follow-up. Our study confirms that OHCA patients represents a peculiar population with the same chance of survival and rate of complications compared to primary and other secondary prevention patients suggesting the need of more studies to improve their long-term treatment.Figure 1 (Panel A, B and C)Figure 2 (Panel A and B)

ID: 328313 DRG Lead Fracture Leads to Return of Pain in a Patient with CPRS Type II

ID: 328313 DRG Lead Fracture Leads to Return of Pain in a Patient with CPRS Type II

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.

Sacral neuromodulation in pediatric refractory bladder and bowel dysfunction Insights from Canada's first pediatric cohort.

Refractory bladder and bowel dysfunction (BBD) significantly affects the health and quality of life of children and their caregivers, emphasizing the need for effective and minimally invasive treatments. This study aims to present the inaugural Canadian experience using sacral neuromodulation (SNM ) as a therapeutic option for children with refractory BBD. Patients <18 years old with refractory BBD were prospectively followed from 2018 to the present. Preoperative evaluation included spinal MRI and video urodynamics. Two-stage SNM implantation was executed with a minimum two-week stage 1 trial. Functional outcomes and complication rates were measured following validated questionnaires. Six patients completed staged implantation at a median age of 10.8 years (range 8.2-18). The median baseline Dysfunctional Voiding Scoring System (DVSS) score was 12.5 (10-22). At six months of followup, only one patient required adjunct bladder medication. Median DVSS at one-year followup was 5.5 (0-7). Symptomatic resolution was noted in three patients at six months, sustained over one year. Early surgical complications were reported in one (infection) and late complications in three (lead fracture, battery depletion, non-traumatic malfunction), requiring reimplantation at a median of 37.5 (1-49) months. Post-SNM reimplantation, oral medication and rectal therapy decreased, and DVSS scores improved by 30% (0-63.6) at six months. SNM is feasible and offers promising results for refractory pediatric BBD in Canada. The significant improvement of symptoms highlights the treatment's potential, which must be balanced against the high need for revision detected at three years, possibly related to patients' growth and high activity level.

Very early fractures of the stylet-driven Biotronik Solia lead used for left bundle branch area pacing

Abstract Introduction Left bundle branch area pacing (LBBAP) has become increasingly popular due to the relatively simple implantation procedure allowing for conduction system pacing (CSP). Initially, lumen-less leads have been used primarily for CSP. However, several authors have published encouraging results using conventional stylet-driven pacemaker (PM) leads as well and our centers have largely adopted this approach. Methods In our two tertiary referral centers, we assessed all patients, who underwent a LBBAP lead implantation using any lead. We observed several early lead fractures, exhibiting a unique failure mechanism, which we illustrate in this case-series. Results Between January 2022 and November 2023 343/393 patients (87.3%) were implanted with a Solia pacemaker lead, 46/393 (11.7%) received a SelectSecure 3830 lead, and 4/393 (1.0%) another stylet-driven lead. Three patients (0.8%) who initially were implanted with a Solia lead experienced very early intracardiac lead fractures within 1, 11 and 13 months after implantation despite good initial electrical performance values (Table shows initial values and values during the time of failure (bold)). The first case was a 54 year-old woman with permanent 3d degree AV block receiving an LBBAP lead after lead extraction. Four weeks later, she presented with presyncope and exit block at maximum output in uni- and bipolar configuration. The second case was a 72 year-old man with intermittent 3rd degree AV block in the context of an ischemic heart disease. He received a dual-chamber LBBAP PM. 13 months after the implantation, a bipolar impedance &amp;gt; 2’500Ω and exit block were noted. The third case was 65 year-old man suffering from sick sinus syndrome. He initially underwent a dual-chamber PM implantation in 2011 and due to ventricular sensing issues a transvenous lead extraction and implantation of a LBBAP lead in October 2022. During device follow-up after 11 months, a fractured LBBAP lead with bipolar impedance &amp;gt;2’500Ω and exit block during threshold testing was noticed. In all cases, X-rays and macroscopic analysis consistently showed a disintegration of the lead immediately distal to the ring electrode (Figure; site of fracture marked with an arrow). Most likely, this was caused by the repetitive shear stress at the hinge point of the lead where it is entering the septum. Conclusion No dedicated stylet-driven CSP lead is available to date. The implantation site and technique for LBBAP may exert higher mechanical stress on the distal part of the lead, making it more prone to fracture than in a conventional position. Currently, the use of conventional stylet-driven leads is still off-label and the performance of such leads should be monitored closely.TableFigure

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.

Substernal lead removal: experience from the EV ICD pivotal study

Abstract Background The extravascular implantable cardioverter defibrillator (EV ICD) has recently emerged as a new option for guideline indicated ICD patients. Previous study results from the EV ICD Pilot and Pivotal studies have demonstrated that the device can provide safe and effective therapy through chronic follow up. However, less has been reported regarding EV ICD lead removal. Purpose To report on the experience of lead removal in the EV ICD Pivotal Study. Methods The EV ICD Pivotal study was an international, prospective, single-arm, premarket clinical study. Patients with a class I or IIa indication for a single-chamber ICD per ESC or ACC/AHA/HRS guidelines were enrolled. Lead removal summary data was reported. Results Of 316 patients with an implant attempt, (74.7% male, age 53.8±13.1 years, 82% primary prevention, LVEF of 38.9%±15.4%, and NYHA Class I [23.7%] or II/III [65.5%]) 299 were fully implanted; 17 (5.7%) of which had a lead removal procedure (14–752 days post-implant, at 13 sites) with 3 of them having been implanted for more than 1 year. Reasons for lead removal were lead dislodgement (n=7), infection (n=5), high impedance alert due to lead fracture (n=2), pacing indication (n=1), cardiac transplant (n=1), or scheduled sternotomy (n=1). New EV ICD leads were placed in 7/17 (41.2%) patients. No serious adverse events were adjudicated as related to the explant procedures. There was a single observation of incision site haemorrhage, that was resolved with wound care. Additional details on lead removal will be included at the time of presentation. Conclusions The EV ICD lead was successfully removed 14-752 days post implant. Nine patients were re-implanted with either extravascular or transvenous systems. Longer term extraction data collection is ongoing through the EV ICD Pivotal study and through the EV ICD post-approval study and will continue to provide additional insights.Lead removed 24 months post-implant.

Safety, efficacy, and reliability evaluation ofa novel small-diameter defibrillation lead: Global LEADR pivotal trial results

BackgroundImplantable cardioverter-defibrillators last longer, and interest in reliable leads with targeted lead placement is growing. The OmniaSecure defibrillation lead is a novel, small-diameter, catheter-delivered lead designed for targeted placement, based on the established SelectSecure SureScan MRI Model 3830 lumenless pacing lead platform. ObjectiveThis trial assessed safety and efficacy of the OmniaSecure defibrillation lead. MethodsThe worldwide LEADR pivotal clinical trial enrolled patients indicated for de novo implantation of a primary or secondary prevention implantable cardioverter-defibrillator or cardiac resynchronization therapy defibrillator, all of whom received the study lead. The primary efficacy end point was successful defibrillation at implantation per protocol. The primary safety end point was freedom from study lead–related major complications at 6 months. The primary efficacy and safety objectives were met if the lower bound of the 2-sided 95% credible interval was >88% and >90%, respectively. ResultsIn total, 643 patients successfully received the study lead, and 505 patients have completed 12-month follow-up. The lead was placed in the desired right ventricular location in 99.5% of patients. Defibrillation testing at implantation was completed in 119 patients, with success in 97.5%. The Kaplan-Meier estimated freedom from study lead–related major complications was 97.1% at 6 and 12 months. The trial exceeded the primary efficacy and safety objective thresholds. There were zero study lead fractures and electrical performance was stable throughout the mean follow-up of 12.7 ± 4.8 months (mean ± SD). ConclusionThe OmniaSecure lead exceeded prespecified primary end point performance goals for safety and efficacy, demonstrating high defibrillation success and a low occurrence of lead-related major complications with zero lead fractures.

Cardiovascular images: pacemaker-lead fracture and excessive coiling in a dog

A seven-year-old male castrated Labrador Retriever presented emergently due to concern for pacemaker malfunction five years after successful transvenous pacemaker implantation to treat partial atrial standstill. On presentation, the dog's pulse rate was 30–50 beats per minute. An electrocardiogram showed no spontaneous atrial activity or paced ventricular activity. Pacemaker interrogation revealed an increased impedance of 7557 ohms, indicating a lead malfunction. Thoracic radiographs confirmed the lead was fractured and had excessive coiling. The transvenous pacing system was turned off, left in place, and an epicardial pacing system was implanted the following day. The dog was discharged with no perioperative complications. The dog eventually required escalated medical therapy for progressive cardiac disease and was euthanized two years after implantation of the replacement pacemaker. This manuscript illustrates a complete lead fracture and excessive lead coiling, which has not previously been detailed in veterinary medicine.

Lead performance of stylet-driven leads in left bundle branch area pacing: Results from a large single-center cohort and insights from in vitro bench testing

BackgroundLeft bundle branch area pacing (LBBAP) requires deep septal lead deployment for left-sided conduction stimulation. Advancing leads toward deep septal positions might add mechanical stress on these leads. Concerns about lead performance and reliability remain an unanswered question. ObjectiveThe purpose of this study was to analyze lead performance and integrity of stylet-driven pacing leads (SDLs) for LBBAP. MethodsThis study assessed lead fracture rates of SDL in a large single-center cohort of adult LBBAP patients. Fluoroscopic analysis of lead bending angulations at the septal insertion point and in vitro bench testing of lead preconditioning were performed to simulate clinical use conditions. Lead performance was compared between LBBAP and conventional right ventricular apical pacing (RVp) sites. ResultsThe study included 325 LBBAP patients (66% male; age 71±15 years). During median follow-up of 18 months, 2 patients (0.6%) experienced conductor fracture between tip housing and ring electrode, whereas no such fractures occurred with RVp patients (n = 149; P = .22). X-ray analysis revealed that high lead bending angulations occurred in 1.3% of the patients. Accelerated bench testing of excessive preconditioned leads showcased a higher probability of early conductor fracture compared to standard preconditioned leads. ConclusionThe incidence of early conductor failure in LBBAP seems higher than with conventional RVp sites. The most vulnerable lead part seems to be the interelectrode space between the tip housing and ring electrode. Excessive angulation and preconditioning might contribute to early fatigue fracture.

Unanticipated subcutaneous ICD end-of-service due to premature battery depletion and occurrence of lead fracture: A single centre experience

The use of subcutaneous ICDs (S-ICD) is growing over years despite increasing alerts on premature battery depletion (PBD) and lead fractures leading to unanticipated device replacements. In our single-centre study including 192 patients, per year analysis demonstrated that incidence of PBD is higher than previously reported with overall greatest battery replacement requirements around the fifth year of follow-up. The underlying issue appears to be limited to old series devices, but only a longer follow-up will clarify the real impact of this phenomenon on patient outcomes. PBD is an underestimated S-ICDs issue and if the hereby demonstrated trend were to be confirmed in latest device series, this would bring significant concerns to patient safety and huge economic expense to health system.

Upper airway stimulation device failure: A 7-year single center experience

ObjectiveTo identify and report a single center experience with upper airway stimulator device-related failures. Study designRetrospective case series. SettingSingle tertiary academic center. MethodsRetrospective data on 352 patients who underwent UAS surgery with an Inspire device from 2016 to 2023 was collected, including demographics, comorbidities, and nature of device failure requiring revision surgery. ResultsOut of the 348 patients included in our analysis, 16 (4.6 %) required revision due to device failure, with an average interval of 772 days (∼2 years) between initial implant and revision. Most failures were attributed to respiratory sensing lead damage (n = 11, 68.8 %), resulting in high system impedance and subsequent device malfunction. Lead fracture causes varied, including idiopathic occurrences and potential trauma. Lead migration was noted in one case (6.3 %), where the hypoglossal electrode detached from the nerve. Two patients (12.3 %) required implantable pulse generator (IPG) replacement, one after experiencing trauma and the other due to unclear source of malfunction. One patient (6.3 %) required complete system replacement following high lead impedance and absent tongue motion. The last patient required replacement of both the IPG and respiratory lead after experiencing high lead impedance (6.3 %). ConclusionRespiratory sensing lead fracture emerged as the leading cause of device failure in this cohort, underscoring the need to address this under-reported issue, potentially linked to the time lapse after device implantation.

Cassandra speaks: a case series of unanticipated subcutaneous ICD premature battery depletion in a single-centre experience

Abstract Background Subcutaneous ICDs (S-ICD) are a valuable option in sudden cardiac death prevention. The main advantage over conventional transvenous ICDs is the absence of intravascular hardware for patients without the need for cardiac stimulation, resynchronization therapy or anti-tachycardia pacing. The claim of reduced lead-related complications has on the contrary been challenged by recent warnings of unexpected lead fracture. Moreover, concerns related to premature battery depletion (PBD) leading to unanticipated device replacement are increasing. Purpose To evaluate retrospectively the incidence of unanticipated S-ICD premature battery depletion in a single-centre experience. Method 168 consecutive patients implanted with S-ICD from February 2015 to November 2022 in our tertiary cardiology centre were included in this study. 4 patients moved to other sites and were thus lost to follow-up, leaving a total of 164 patients. PBD was defined as the occurrence of battery depletion requiring generator replacement earlier than 60 months post-implantation in the absence of therapy being delivered, or as a result of manufacturer recommendations. Results Most patients were implanted for primary prevention (101 patients, 60%). The main aetiology was hypertrophic cardiomyopathy (47 patients, 28%), followed by arrhythmogenic (35, 21%) and dilated idiopathic cardiomyopathy (24, 14%). Mean age and left ventricular ejection fraction at baseline were 46±18yrs and 51±16%, respectively. Over a total follow up period of 44±25 months, at 58±17 months following implantation 19 (11,6%) patients needed early replacement due to PBD, while 2 (1.2%) patients had lead fracture after respectively 41 and 26 months, for a total of 12,8% of patients with system-related complications. In addition to those patients requiring early replacement due to PBD or lead fracture, two underwent S-ICD extraction due to infection. Analysis of freedom from unanticipated PBD per year of implantation showed higher rates in years 2016 and 2017, with 67% and 27% of all implanted patients, respectively (Figure 1). Conclusions In this study, the incidence of PBDs appear to be higher than reported in literature though confined to a limited device series. However, if on the contrary the trend should remain remarkably high, that would not only endanger patients health due to repeated replacements, but also pose a huge economic burden to health systems.

Abstract 165: Subarachnoid Hemorrhage Related to Thoracic Spinal Cord Stimulator Placement

Introduction Spinal cord stimulators (SCS) offer safe and effective pain relief. Precise lead placement is critical. Indications for lead placement include chronic pain, failed back surgery syndrome and complex regional pain syndrome (1). Hardware related complications include lead fracture and lead migration into the subdural space. Complications can also include spinal cord injury, nerve root damage or lack of desired pain control (2). We present a case of subarachnoid hemorrhage (SAH) due to SCS lead migration into the subdural space. Methods An 81‐year‐old female patient with a past medical history of heart failure, atrial fibrillation and a mechanical mitral valve, presents with a severe headache and right hemiparesis. The patient was anticoagulated with a warfarin to heparin bridge. One week prior to presentation, the patient underwent SCS placement for chronic lower back pain due to post herpetic neuralgia. She was also found to have 8/10 pain on palpation of the lumbar spine and loss of sensation in the right lower extremity. An urgent CT brain revealed a SAH in the bilateral occipital lobes, right sylvian fissure and right temporal lobe. CT angiogram was also performed and did not reveal any evidence of a cerebral aneurysm. CT of the thoracic spine revealed neurostimulator lead migration into the subdural space. Neurosurgery was consulted and subsequently removed the SCS. The patient’s hemiparesis resolved, and CT brain showed no progression of the hemorrhage. MRI brain showed no infarct. Results We propose that the combined risk of anticoagulation and lead migration into the subdural space led to the development of SAH. Conclusion In cases of a SAH, where a cerebral aneurysm or arteriovenous malformation have been excluded, other sources should be considered. We report a novel case of SAH following SCS placement.

Lead management in patients undergoing percutaneous tricuspid valve replacement or repair: a 'heart team' approach.

Clinically significant tricuspid regurgitation (TR) has historically been managed with either medical therapy or surgical interventions. More recently, percutaneous trans-catheter tricuspid valve (TV) replacement and tricuspid trans-catheter edge-to-edge repair have emerged as alternative treatment modalities. Patients with cardiac implantable electronic devices (CIEDs) have an increased incidence of TR. Severe TR in this population can occur for multiple reasons but most often results from the interactions between the CIED lead and the TV apparatus. Management decisions in patients with CIED leads and clinically significant TR, who are undergoing evaluation for a percutaneous TV intervention, need careful consideration as a trans-venous lead extraction (TLE) may both worsen and improve TR severity. Furthermore, given the potential risks of 'jailing' a CIED lead at the time of a percutaneous TV intervention (lead fracture and risk of subsequent infections), consideration should be given to performing a TLE prior to a percutaneous TV intervention. The purpose of this 'state-of-the-art' review is to provide an overview of the causes of TR in patients with CIEDs, discuss the available therapeutic options for patients with TR and CIED leads, and advocate for including a lead management specialist as a member of the 'heart team' when making treatment decisions in patients TR and CIED leads.

ID: 205748 A Case of Open Surgical Dorsal Root Ganglion Stimulator Implantation: A Novel Approach

Neuromodulation at the Dorsal Root Ganglion (DRG) has been used to treat chronic neuropathic pain conditions including CRPS of the lower extremity and pelvic pain syndromes1. It is particularly useful in cases where traditional dorsal column stimulation may not provide optimal efficacy and can provide a more targeted treatment2. DRG stimulators are typically inserted percutaneously under fluoroscopic guidance. In certain populations, however, this approach may prove to be challenging and open surgical approaches may be more feasible, while limiting the risk of long-term lead fracture or migration.

Gradually increasing impedance in patients with pacemakers and implantable defibrillators: a watchful waiting strategy

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): hospital resources Introduction Pacing impedance measurements are important in the surveillance of pacemaker and implantable cardioverter/defibrillator (ICD) devices. Whereas sudden changes in impedances can reflect lead fracture or isolation defects, gradually increasing impedances are thought to occur because of calcifications at the endomyocardial interface. In many cases, these leads are replaced prophylactically but this has not been studied systematically. Purpose We aimed to identify the outcome of right ventricular (RV) electrodes with high impedances that were left active in this single center study. Methods All patients in the electronic patient database were screened for impedances &amp;gt;1200Ohms. 41,201 individual recordings led to 219 individual patients. 161 patients were excluded from the analysis due to sudden impedance increase, temporarily high impedances or wrong entry. Of the remaining 58 patients, baseline characteristics as well as pacing impedance, sensing values, pacing thresholds, and shock impedance in case of ICDs were recorded. Results There were 17 pacemaker and 41 ICD patients, 68±15 years old, 69% were male. Glomerular filtration rate at baseline was 81±22 ml/min/1.73m2. Baseline RV impedance was 597±123Ohms. During follow-up impedances increased to 1875±682Ohms (p&amp;lt;0,001). Pacing thresholds increased from 0,6±0,4V to 3,0±1,9V (p&amp;lt;0,001). Sensing remained stable. The median time from implant to impedance rise &amp;gt;1000Ohms was 5,5 (3,4-7)years and median follow-up thereafter 3,8 years (1,6-6,6). During follow-up, no intervention was performed for 45 leads (78%). No events occurred. 13 leads (22%) were replaced , 9 prophylactically (mostly because of ICD advisory leads), 3 because of high pacing thresholds and high percentage pacing and one lead because of noise oversensing, probably unrelated as it occurred 7 years after impedance increase. Conclusions A watchful waiting strategy appears to be a safe option for patients with ICDs and pacemakers with low percentage pacing. As impedance increase cannot be used for surveillance for imminent lead fracture, other means such as short interval counts and non-sustained oversensing have to be employed and should be combined with remote monitoring.

Reducing radiation exposure and incision time in pacemakers implantation procedures using direct percutaneous axillary vein puncture

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Radiation exposure during device implantation depends overall on the operator experience but also on the type of venous access, type of device and number of leads implanted. Purpose to investigate radiation exposure/incision time for uni/bicameral pacemakers (PM) implantation procedures using direct percutaneous axillary vein puncture without primary fluoroscopy guidance and to assess the safety and the efficiency of this procedure strategy. Methods single center retrospective cohort study of patients implanted with unicameral and bicameral PM between January 2020 and December 2020 using direct percutaneous axillary vein puncture. All pts were given detailed explanations and informed consent. Procedural steps were: (I) direct percutaneous axillary vein puncture (anatomical landmarks: 1 or 2 cm medial and parallel to the deltopectoral groove at the level of the coracoid process); obtain separate vein access: 1 or 2 punctures; (II) skin incision and subcutaneous pocket dissection; (III) right ventricle (RV) ± right atrium (RA) lead placement and fixation. We analyzed the following data: fluoroscopy/incision time, dose area product (DAP) and the outcome related to procedure difficulties and complications. Results We collected data from 209 consecutive implant procedures; 152 patients (pts) underwent bicameral PM implantation, 57 pts received a unicameral device. All the procedures were done by the same operator (54 yo, 22 years of experience in PM implantation) using axillary access alone (2 years' experience in this technique). In 37 patients (18%) fluoroscopy guided puncture was needed. The mean fluoroscopy time was: bicameral PM 1.2±1.0 min (average incision time: 8.4±5.2 min); unicameral PM 0.4±0.3 min (average incision time: 6.5±4.3 min). The mean DAP was: bicameral PM 0.00358±0.00545 mGy/cm2; unicameral PM 0.00285±0.00449 mGy/cm2. In short term follow-up 1 patient (0.4%) developed pneumothorax and subsequent drainage was needed. Total follow-up period 19.7±4.3 months: at 6 months follow-up 1 patient (0.4%) presented lead fracture; 1 patient with DDD PM (0.4%) presented pocket infection; leads extraction were successful performed and another device was implanted. No other complications were noted. Conclusion Single venous access using axillary vein puncture was associated with reduced radiation exposure and decreased incision time. Our data showed a low incidence of complications.

P160 WHEN IMPEDANCE TRENDS LIE, REMOTE MONITORING HELPS FOR DIAGNOSIS

Abstract An 82–years old female patient with history of hypertension, diagnosis of dilatative cardiomyopathy with normal coronary arteries and permanent atrial fibrillation (AF) was implanted with a dual chamber implantable cardioverter defibrillator (ICD), Guidant Ventak Prizm DR (Boston Scientific,Marlborough,USA) as a secondary prevention of sudden cardiac death in 2002. The ICD was electively replaced in 2005 and in 2010 with a Guidant, Vitality 2 DR (Boston Scientific,Marlborough,USA). In 2016, despite an optimized medical therapy, the patient experienced an episode of palpitation due to an AF with high ventricular response. Considering the difficulties of the heart rate management with the pharmacological therapy the patient underwent to an ablation of AV node. In 2017 we performed a third replacement of the ICD downgrading the system to a single chamber ICD, Fortify Assura VR (Abbott,Sylmar,USA) and providing the patient with a bedside–transmitter Merlin@home (Abbott,Sylmar,USA) The patient, followed for 4 years remotely, did not experience ventricular arrhythmias and the ventricular lead electrical parameters, including pacing and shock impedances, were stable and in the normal range. In March 2021 an alert of the Merlin system triggered an unscheduled transmission that showed several episodes of ventricular oversensing. The episodes revealed that an electrical interference inhibited the ventricular pacing causing episodes of asystole with a maximum duration of three seconds (Fig.1). Unexpectedly electrical parameters such as the pacing and shock impedances showed a stable and normal measurements (Fig .2), while the chest X–rays showed that the ventricular lead was kinked at 90–degrees below the clavicle evidencing a lead fracture (Fig.3). The patient was therefore implanted with a new ventricular lead avoiding inappropriate shocks and further episodes of asystole. The occurrence of a lead failure represents an insidious and potentially harmful event for the device implanted population, especially for ICD or pacemaker–dependent patients. The diagnosis of a lead failure is not easily predictable, and it is usually driven after a clinical event of inappropriate shock or unexplained syncope. Our case highlighted how Remote Monitoring is extremely helpful even more in this case of apparently correct functioning based on electric measurements.

CE-454611-1 ISOLATED HIGH SHOCK IMPEDANCE DUE TO CALCIFIED POCKET AND THE MANAGEMENT

Impedance is the ratio of voltage to current in an electrical circuit. The most common causes of high shock impedance are lead conductor fracture and lead calcification often associated with lead malfunction. We present the first two cases of isolated high shock impedance from pocket calcification in which the lead function is normal. Case 1: A 73-year-old male with ICM, EF 10%, LBBB, sever COPD and Boston biventricular (BiV) ICD in 2013 that normalized EF. Shock impedance slowly rose from 70 Ω to 122 Ω in 2019 and 189 Ω in 2021. Lead extraction with a new system was considered at the time for generator exchange; however, the patient declined. The pocket was severely calcified, with normal defibrillator lead pacing parameters (pace impedance 796 Ω, pace threshold 0.8 V @ 0.4 msec). The calcium shell was removed (Figure 1A), and the shock impedance dropped to 146 Ω, and remained 137 Ω in one year follow up. Case 2: A 65-year-old female with NICM, EF 20%, LBBB, and Boston BiV ICD in 2013 that normalized QRS (Figure 1B). Shock impedance slowly rose from 65 Ω to 138 Ω (2019) and 165 Ω (2022). At the time of generator exchange, the pocket was heavily calcified. Defibrillator lead pacing parameters were normal (pace impedance 868 Ω, pace threshold 0.6 V @ 0.4 msec). After pocket decalcification, shock impedance reduced to 128 Ω. At one month follow up, shock impedance was stable at 130 Ω. N/A High shock impedance is a result of increased impedance in the circuit which includes the can. Lead fracture or calcification will alter lead function as well as shock impedance. This is managed by extraction. In contrast, pocket calcification, which only increases shock impedance, and can be easily managed by pocket decalcification. In both cases, patients benefited greatly from keeping their functional device and avoiding lead exchange. Lead fracture often results in abrupt increase in shock impedance. Calcification at the lead tip or at the pocket causes slow impedance rise. Unipolar and bipolar pacing impedance can also be used to localize the area of calcification. Normal bipolar pacing impedance and slow isolated high shock impedance should raise the suspicion of pocket calcification. Our cases highlight the importance of recognizing pocket calcification in the context of high shock impedance. Calcium removal at the pocket significantly reduces shock impedance. This management strategy can help to avoid lead extraction, a potentially high-risk operation.