Transvenous ICD Research Articles

Abstract 13663: 90-day Safety and Performance Outcomes With a Novel Extravascular ICD Lead

Introduction: Long-term transvenous implantable cardioverter defibrillator (ICD) leads have many pitfalls. There is in development a novel extravascular (EV) ICD lead for sensing and defibrillation of ventricular tachyarrhythmias (VT/VF) utilizing commercially available DF-4 ICD pulse generators. We evaluate here 90-day safety and performance outcomes for delivery, stability, sensing, and defibrillation using this prototype EV lead. Methods: 18 patients scheduled to undergo de novo or replacement ICD were enrolled in a prospective, nonrandomized study (SECURE-EV STUDY). Each subject was simultaneously implanted with EV ICD lead (AtaCor, SanClemente, CA) attached to a commercially available ICD pulse generator. Study lead was delivered with a designed tool into left parasternal anterior mediastinum via a selected 4th, 5th or 6th intercostal space. Over 90 days pts were evaluated intermittently for defibrillation energy requirements, matched sensing events between both devices, stability of lead position and adverse events. Results: 16/18 of enrolled subjects received study device. Lead failed implant in 2 due to (1) intercostal ossification and (1) mediastinal adhesions. Prior to 30-days, 4 subjects were withdrawn from study due to pneumothorax, wound dehiscence, death unrelated to IV-ICD implantation and early elective lead removal. Over 90-days of simultaneous sensing, 4 events of VT/VF in 3 pts were detected by both devices. There was 1 AF discrimination error & 1 atrial oversensing event detected by both devices. There were 4 events of non-cardiac noise in 4 pts detected by EV-ICD only. 1 event of Twave oversensing was detected by TV-ICD. 23 conversion tests in 13 subjects were performed at energy (26 to 30 J delivered, 1 tested with 35J) at 30- and 90-day visits, with successful conversion in all 23. Mean time between fibrillation detection and shock delivery was 10.7 seconds. Conclusion: This study showed feasibility of sensing and defibrillating induced VT/VF with intercostal placed prototype extravascular ICD lead. Findings with ICD lead was consistent across 4 commercially available ICDs. Simultaneous sensing of VT/VF in ambulatory pts was matched. Non-cardiac inappropriate sensing with EV-ICD lead is being addressed in new prototype.

Abstract 17080: Subcutaneous Implantable Cardioverter Defibrillator in Hypertrophic Cardiomyopathy: A Systematic Review and Meta-Analysis

Background: The subcutaneous implantable cardioverter-defibrillator (S-ICD) is an alternative to transvenous implantable cardioverter-defibrillator (TV-ICD), mitigating the risks associated with transvenous leads. However, the effects of S-ICD in hypertrophic cardiomyopathy (HCM) remains uncertain. Thus, we performed a systematic review and meta-analysis to assess the efficacy and safety of S-ICD in treating patients with HCM. Methods: We systematically searched PubMed, Embase and Scopus on April 2023 for studies comparing S-ICD to TV-ICD in patients with HCM. Key endpoints of interest included incidence of appropriate shocks (AS), inappropriate shocks (IAS), and device-related complications. Odds ratios (ORs) and their 95% confidence intervals (CIs) were computed using a random-effects model. Heterogeneity was assessed with I 2 statistics, and a p-value of <0.05 was considered statistically significant. Results: We screened 1070 records. Six studies comprising 3,820 patients were included, of whom 2,497 (65.4%) were male. Mean age ranged from 39.1 to 49.4 years. Our pooled analysis indicated that device-related complications were significantly less frequent in the S-ICD group compared with the TV-ICD group (OR 0.39; 95% CI 0.18 to 0.82; p=0.01; Figure 1A). However, the incidences of AS (OR 0.56; 95% CI 0.20-1.57; p=0.27) and IAS (OR 1.26; 95% CI 0.61 to 2.59; p=0.54; Figure 1B) were not significantly different between the two groups. Conclusions: These findings suggest that S-ICD are associated with fewer device-related complications as compared with TV-ICD, among patients with HCM. Appropriate and inappropriate shocks are not significantly different between the two strategies.

Combined subcutaneous implantable cardioverter defibrillator and pacemaker devices in complex congenital heart disease: a single-center experienced based study.

Subcutaneous implantable cardioverter defibrillators (S-ICD) are widely accepted therapy in congenital heart disease (CHD) patients at risk of life-threatening ventricular arrhythmias or sudden cardiac death (SCD) when pacing is not required. Occasionally, pacemaker (PM)-dependent CHD patients will subsequently develop an indication for a cardioverter defibrillator. The use of S-ICD in complex CHD patients who have had already PM devices implanted implies some specific considerations, as the safety for these patients in unknown and recommendations among physicians may vary widely. We review the data and studied the indications for S-ICD in complex CHD with previous PM and discuss its usefulness in clinical practice. From a large cohort of 345 patients enrolled in the S-ICD Monaldi care registry, which encompass all the patients implanted in the Monaldi Hospital of Naples, we considered 11 consecutive complex CHD patients (10M/1F aged 40.4 ±18.4 years) who underwent S-ICD implant after a previous PM implant, from February 2015 to October 2022. Mean follow-up was 25.5 ± 22 months. All the patients showed a good compliance to the device system with no complications (infections or skin erosions). In complex CHD with already implanted PM devices, S-ICD implant appears to be a safe alternative to PM upgrading to transvenous ICD system, avoiding abandoned leads or life-threatening lead extraction. However, there are important issues with regard to testing and programming that need to be addressed at the time of implantation.

The Subcutaneous Implantable Cardioverter-Defibrillator: A Patient Perspective.

The subcutaneous implantable cardioverter-defibrillator (S-ICD) is a new technology for the management of ICD patients. But what is the patients' perspective? Previous studies on the transvenous ICD (TV-ICD) showed that device implantation is related not only to anxiety and depression because of the fear of ICD shocks, but also to many biopsychosocial factors like body image changes, perceived reduction of socialization and limitation in professional and sports activities. Anxiety and distress are more evident in younger women because of aesthetic reasons. The scar size and the position of the S-ICD can help these patients and positively influence their social relationships. Moreover, the position of the S-ICD reduces possible complications from catheters due to stress injury and can improve patients' professional life by avoiding some work activity limitations. An S-ICD can be also a good option for athletes in avoiding subclavian crash and reducing inappropriate shocks. However, some questions remain unsolved because an S-ICD is not suitable for patients with indications for pacing, cardiac resynchronization therapy or anti-tachycardia pacing. In conclusion, the use of an S-ICD can assist physicians in reducing the negative impact of implantation on the well-being of some groups of patients by helping them to avoid depression and anxiety as well as improving their noncompliance with their medical treatment.

Revascularization and Left Ventricular Dysfunction for ICD Eligibility.

Common triggers for sudden cardiac death (SCD) are transient ischemia, hemodynamic fluctuations, neurocardiovascular influences, and environmental factors. SCD occurs rapidly when sinus rhythm degenerates into ventricular tachycardia (VT) and/or ventricular fibrillation (VF), followed by asystole. Such progressive worsening of the cardiac rhythm is in most cases observed in the setting of ischemic heart disease and often associated with advanced left ventricular (LV) impairment. Revascularization prevents negative outcomes including SCD and heart failure (HF) due to LV dysfunction (LVD). The implantable cardioverter-defibrillator (ICD) on top of medical therapy is superior to antiarrhythmic drugs for patients with LVD and VT/VF. The beneficial effects of ICD have been demonstrated in primary prevention of SCD as well. However, yet debated is the temporal management for patients with LVD who are eligible to ICD prior to revascularization, either through percutaneous or surgical approach. Restoration of coronary blood flow has a dramatic impact on adverse LV remodeling, while it requires aggressive long-term antiplatelet therapy, which might increase complication for eventual ICD procedure when percutaneous strategy is pursued; on the other hand, when LV and/or multiorgan dysfunction is present and coronary artery bypass grafting is chosen, the overall risk is augmented, mostly in HF patients. The aims of this review are to describe the pathophysiologic benefits of revascularization, the studies addressing percutaneous, surgical or no revascularization and ICD implantation, as well as emerging defibrillation strategies for patients deemed at transient risk of SCD and/or at higher risk for transvenous ICD implantation.

ICD outcome in pediatric arrhythmogenic cardiomyopathy

BackgroundArrhythmogenic cardiomyopathy (ACM) is a very rare condition among pediatric patients. Sudden cardiac death (SCD) is the main complication and often requires ICD implantation.Aim of the study is the evaluation of the outcomes of ICD implanted ACM pediatric patients in terms of safety, efficacy and complications. MethodsAll pediatric patients (<18 y.o.) diagnosed with ACM and who were implanted with ICD since 2009 in Our Institution were collected. Implantation was decided according to current recommendations/ guidelines, and outcome was recorded during follow-up. ResultsNineteen consecutive ACM patients were implanted with ICD. Subcutaneous ICDs (S-ICD) were implanted in 15 patients (79%) while transvenous ICDs (TV-ICD) in 4 patients (21%). Mean age at implantation was 14.3 ± 2.1 y.o. ICDs were implanted for secondary prevention in 4 (21%) patients, and for primary prevention in 15 (79%). During the follow-up (5.59 ± 3.4 years), appropriate ICD interventions were delivered in 4 (21%) patients for sustained VTs, [2 implanted in primary prevention (13%) and 2 in secondary prevention (50%)]. No defibrillation failures occurred. Inappropriate shocks occurred in 2 cases (10.5%). Device-related complications requiring device revision occurred in 3 (16%): lead dislodgement, surgical skin erosion and sensing defect. ConclusionsIn a pediatric ACM cohort, appropriate ICD therapies occurred in a minority of primary prevention patients and frequently in secondary prevention patients. The rate of inappropriate shocks and device-related complications were even more rare and mostly wound related. Therefore, ICD therapy in pediatric ACM is effective and safe.

Impact of Age on Subcutaneous Implantable Cardioverter-Defibrillator in a Large Patient Cohort: Mid-Term Follow-Up

BackgroundThe subcutaneous implantable cardioverter-defibrillator (S-ICD) is an accepted alternative to transvenous (TV) ICD to provide defibrillation therapy to treat life-threatening ventricular tachyarrhythmias in high-risk patients. S-ICD outcomes by age group have not been reported. ObjectivesIn this study, the authors sought to report S-ICD outcomes in different age groups in a multicenter S-ICD post-approval study (PAS) involving the largest cohort of patients ever reported. MethodsPatients were prospectively enrolled in the S-ICD PAS and stratified based on age: young, aged 15-34 years; adult, aged 35-69 years; and elderly, aged ≥70 years. Patient characteristics and clinical outcomes through 3 years of follow up after implantation were compared. ResultsThe S-ICD PAS enrolled 1,637 patients. Elderly patients were more likely to receive an S-ICD as a replacement of a TV-ICD (15.1% elderly vs 12.3% adult vs 7.4% young). Secondary prevention indication decreased with age (32.7% young vs 22.2% adult vs 20.5% elderly). Mortality rate was significantly higher in the elderly group (24.0% elderly vs 13.0% adult vs 7.4% young; P < 0.0001), whereas the complication rate did not differ significantly (12.3% young vs 11.3% adult vs 8.1% elderly). Rates of appropriate shock (12.7% young vs 13.0% adult vs 13.8% elderly) and inappropriate shock (7.8% young vs 9.1% adult vs 8.8% elderly) rates did not differ between groups (P = 0.96 and P = 0.98, respectively). ConclusionsImplant complications and appropriate and inappropriate shock rates were similar among age groups. S-ICD for secondary prevention was more common in the young group. Replacing a TV-ICD for an S-ICD increases with age. (S-ICD System Post-Approval Study; NCT01736618)

Complicaciones y descargas inapropiadas tras el implante de un desfibrilador subcutáneo en pacientes pediátricos

Introduction and objectivesThere is limited evidence regarding the use of subcutaneous implantable cardioverter-defibrillators (S-ICD) in pediatric patients. The aim of this study was to determine the incidence of complications in these patients at our center, according to the type of ICD and patient size. MethodsWe included all patients aged<18 years who received an S-ICD since 2016 at our center. As a control group, we also included contemporary patients (since 2014) who received a transvenous ICD (TV-ICD). The primary endpoint was a composite of complications and inappropriate shocks. ResultsA total of 26 patients received an S-ICD (median age, 14 [5-17] years; body mass index [BMI], 20.2 kg/m2). Implantation was intermuscular in 23 patients (88%) and subserratus in the remainder. Two incisions were used in 24 patients (92%). In all patients, 2 zones were programmed: a conditional zone set at 230 (220-230) bpm, and a shock zone set at 250 bpm. Nineteen patients received a TV-ICD (median age, 11 [range, 5-16] years; BMI, 19.2 kg/m2, 79% single-chamber). Survival free from the primary endpoint at 5 years was 80% in the S-ICD group and 63% in the TV-ICD group (P=.54). Survival free from inappropriate shocks was similar (85% vs 89%, P=.86), while survival free from complications was higher in the S-ICD group (96% vs 57%, cloglogP=.016). There were no therapy failures in the S-ICD group, and no increased complication rates were observed in patients with BMI ≤ 20 kg/m2. ConclusionsWith contemporary implantation techniques and programming, S-ICD is a safe and effective therapy in pediatric patients. The number of inappropriate shocks is similar to TV-ICD, with fewer short- and mid-term complications.Full English text available from:www.revespcardiol.org/en

Real-world evidence for the use of subcutaneous implantable cardioverter-defibrillators in China: Asingle-center experience.

Subcutaneous implantable cardioverter-defibrillators (S-ICDs) have been shown to be non-inferior to transvenous ICDs in the prevention of sudden cardiac death (SCD), but there is still alack of evidence from clinical trials in China. We investigated whether S‑ICD implantation in the Chinese population is safe and feasible and should be promoted in the future. Consecutive patients undergoing S‑ICD implantation at our center were enrolled in this retrospective study. Data were collected within the median follow-up period of 554days. Data concerning patient selection, implantation procedures, complications, and episodes of shock were analyzed. In total, 70.2% of all 47patients (median age = 39years) were included for secondary prevention of SCD with different etiologies. Vector screening showed that 98% of patients were with > 1 appropriate vector in all postures. An intraoperative defibrillation test was not performed on six patients because of the high risk of disease deterioration, while all episodes of ventricular fibrillation induced post implantation were terminated by one shock. As expected, no severe complications (e.g., infection and device-related complications) were observed, except for one case of delayed healing of the incision. Overall, 15patients (31.9%) experienced appropriate shocks (AS) with all episodes terminated by one shock. Two patients (4.3%) experienced inappropriate shocks (IAS) due to noise oversensing, resulting in ahigh Kaplan-Meier IAS-free rate of 95.7%. Based on appropriate patient selection and standardized implantation procedures, this real-world study confirmed the safety and efficacy of S‑ICD in Chinese patients, indicating that it may help to promote the prevention of SCD in China.

Subcutaneous Implantable Cardioverter Defibrillator: A Contemporary Overview.

The difference between subcutaneous implantable cardioverter defibrillators (S-ICDs) and transvenous ICDs (TV-ICDs) concerns a whole extra thoracic implantation, including a defibrillator coil and pulse generator, without endovascular components. The improved safety profile has allowed the S-ICD to be rapidly taken up, especially among younger patients. Reports of its role in different cardiac diseases at high risk of SCD such as hypertrophic and arrhythmic cardiomyopathies, as well as channelopathies, is increasing. S-ICDs show comparable efficacy, reliability, and safety outcomes compared to TV-ICD. However, some technical issues (i.e., the inability to perform anti-bradycardia pacing) strongly limit the employment of S-ICDs. Therefore, it still remains only an alternative to the traditional ICD thus far. This review aims to provide a contemporary overview of the role of S-ICDs compared to TV-ICDs in clinical practice, including technical aspects regarding device manufacture and implantation techniques. Newer outlooks and future perspectives of S-ICDs are also brought up to date.

Initial Experience With Intercostal Insertion of an Extravascular ICD Lead Compatible With Existing Pulse Generators.

This study assessed safety and feasibility of a novel extravascular implantable cardioverter defibrillator (ICD) lead when inserted anteriorly through a rib space and connected to various commercially available ICD pulse generators (PGs) placed in either a left mid-axillary or left pectoral pocket. Currently available or investigational, extravascular-ICDs include a subcutaneous or subxiphoid lead connected to customized extravascular-ICD PGs. This novel extravascular-ICD (AtaCor Medical Inc, San Clemente, CA) employs a unique intercostal implant technique and is designed to function with commercial DF-4 ICD PGs. In this nonrandomized, single-center, acute study, 36 de novo or replacement ICD (transvenous ICD) patients enrolled to receive a concomitant extravascular-ICD lead inserted through an intercostal space along the left parasternal margin. extravascular-ICD leads were connected to DF-4 compatible ICD PGs positioned in either a left mid-axillary or pectoral pocket for acute sensing and defibrillation testing. Defibrillation testing started at 30 Joules (J) and stepped up or down in 5 to 10 joule increments depending on the success and limitations of the generator used. Successful acute defibrillation using ≤35 J was noted in 100% of left mid-axillary PG subjects (n=27, mean 16.3±8.6 J) and 83% of left pectoral PG subjects (n=6, mean 21.0±8.4 J). Furthermore, 24 of 27 (89%) of patients tested with a left, mid-axillary intermuscular PG had successful VF conversion with defibrillation energies at least 10 J below the maximum delivered output of the device. All evaluable episodes (n=93) were automatically sensed, detected, and shocked. No serious device-related intraoperative adverse events were observed. This first-in-human study documented the safe and reliable placement of a novel extravascular ICD lead with effective sensing and defibrillation of induced ventricular fibrillation using commercial DF-4 ICD PGs.

Postapproval Study of a Subcutaneous Implantable Cardioverter-Defibrillator System

BackgroundThe subcutaneous implantable cardioverter-defibrillator (S-ICD) was developed to avoid complications related to transvenous implantable cardioverter-defibrillator (TV-ICD) leads. Device safety and efficacy were demonstrated previously with atypical clinical patients or limited follow-up. ObjectivesThe S-ICD PAS (Subcutaneous Implantable Cardioverter-Defibrillator System Post Approval Study) is a real-world, multicenter, registry of U.S. centers that was designed to assess long-term S-ICD safety and efficacy in a diverse group of patients and implantation centers. MethodsPatients were enrolled in 86 U.S. centers with standard S-ICD indications and were observed for up to 5 years. Efficacy endpoints were first and final shock efficacy. Safety endpoints were complications directly related to the S-ICD system or implantation procedure. Endpoints were assessed using prespecified performance goals. ResultsA total of 1,643 patients were prospectively enrolled, with a median follow-up of 4.2 years. All prespecified safety and efficacy endpoint goals were met. Shock efficacy rates for discrete episodes of ventricular tachycardia or ventricular fibrillation were 98.4%, and they did not differ significantly across follow-up years (P = 0.68). S-ICD–related and electrode-related complication-free rates were 93.4% and 99.3%, respectively. Only 1.6% of patients had their devices replaced by a TV-ICD for a pacing need. Cumulative all-cause mortality was 21.7%. ConclusionsIn the largest prospective study of the S-ICD to date, all study endpoints were met, despite a cohort with more comorbidities than in most previous trials. Complication rates were low and shock efficacy was high. These results demonstrate the 5-year S-ICD safety and efficacy for a large, diverse cohort of S-ICD recipients. (Subcutaneous Implantable Cardioverter-Defibrillator [S-ICD] System Post Approval Study [PAS]; NCT01736618)

S-ICD Implantation "Tips and Tricks".

An implantable cardioverter-defibrillator (ICD) was developed to provide protection against sudden cardiac death. Despite being effective in terminating ventricular arrhythmias, traditional transvenous ICDs appeared over time to have certain limitations related to the need for vascular access and the presence of foreign material inside the circulatory system (namely lead failure and infections). A subcutaneous implantable cardioverter-defibrillator (S-ICD) was developed to overcome those limitations and to provide prevention against sudden cardiac death from outside the cardiovascular system. Utilization of that modern method of treatment is constantly increasing worldwide, and new centers incorporate implantation of that system in their portfolio. This review aims to present the most relevant issues related to S-ICD implantation procedure, based on experience of the authors and an extensive literature search.

Voltage gradients in transvenous and subcutaneous defibrillation and their risk of myocardial damage.

Transvenous implantable cardioverter-defibrillator (ICD) shocks have been associated with cardiac biomarker elevations and are thought in some cases to contribute to adverse clinical outcomes and mortality, possibly from myocardium exposed to excessive shock voltage gradients. Currently, there are only limited data for comparison with subcutaneous ICDs. We sought to compare ventricular myocardium voltage gradients resulting from transvenous (TV) and subcutaneous defibrillator (S-ICD) shocks to assess their risk of myocardial damage. A finite element model was derived from thoracic magnetic resonance imaging (MRI). Voltage gradients were modeled for an S-ICD with a left-sided parasternal coil and a left-sided TV-ICD with a mid-cavity, a septal right ventricle (RV) coil, or a dual coil lead (TV mid, TV septal, TV septal + superior vena cava [SVC]). High gradients were defined as > 100 V/cm. The volumes of ventricular myocardium with high gradients > 100 V/cm were 0.02, 2.4, 7.7, and 0 cc for TV mid, TV septal, TV septal + SVC, and S-ICD, respectively. Our models suggest that S-ICD shocks produce more uniform gradients in the myocardium, with less exposure to potentially damaging electrical fields, compared to TV-ICDs. Dual coil TV leads yield higher gradients, as does closer proximity of the shock coil to the myocardium.

Systematic Review on S-ICD Lead Extraction.

Subcutaneous implantable cardioverter defibrillators (S-ICDs) have emerged in recent years as a valid alternative to traditional transvenous ICDs (TV-ICDs). Therefore, the number of S-ICD implantations is rising, leading to a consequent increase in S-ICD-related complications sometimes requiring complete device removal. Thus, the aim of this systematic review is to gather all the available literature on S-ICD lead extraction (SLE), with particular reference to the type of indication, techniques, complications and success rate. Studies were identified by searching electronic databases (Medline via PubMed, Scopus and Web of Science) from inception to 21 November 2022. The search strategy adopted was developed using the following key words: subcutaneous, S-ICD, defibrillator, ICD, extraction, explantation. Studies were included if they met both of the following criteria: (1) inclusion of patients with S-ICD; (2) inclusion of patients who underwent SLE. Our literature search identified 238 references. Based on the abstract evaluation, 38 of these citations were considered potentially eligible for inclusion, and their full texts were analyzed. We excluded 8 of these studies because no SLE was performed. Eventually, 30 studies were included, with 207 patients who underwent SLE. Overall, the majority of SLEs were performed for non-infective causes (59.90%). Infection of the device (affecting either the lead or the pocket) was the cause of SLE in 38.65% of cases. Indication data were not available in 3/207 cases. The mean dwelling time was 14 months. SLEs were performed using manual traction or with the aid of a tool designed for transvenous lead extraction (TLE), including either a rotational or non-powered mechanical dilator sheath. SLE is performed mainly for non-infective causes. Techniques vary greatly across different studies. Dedicated tools for SLE might be developed in the future and standard approaches should be defined. In the meantime, authors are encouraged to share their experience and data to further refine the existing variegated approaches.

Features of subcutaneous cardioverter-defibrillators implantation

According to global statistics, 25% of deaths every year are cases of sudden cardiac death. Implantation of cardioverter-defibrillators is currently used as its prevention. In the coming years, the world is projected to see an increase in the number of implantations of cardioverter-defibrillators in high-income countries, as well as an expansion of the range of medical devices offered, including subcutaneous cardioverter-defibrillators, which are currently being considered as a promising alternative. We systematized the literature data presented in various international studies evaluating the efficacy and safety of the use of subcutaneous cardioverter-defibrillators. Areview of the medical literature published in the period from 2015 to 2022 was carried out using the information and analytical systems MEDLINE, Scopus, Clinicaltrials.gov, Google Scholar and Web of Science. The review was performed in accordance with the checklist of preferred reporting items for systematic reviews and meta-analyses. 398original publications were selected, of which 50original scientific articles on the research topic were included in the analysis. Modern international studies have demonstrated the efficacy and safety of the use of subcutaneous implantable cardioverter defibrillators. An improvement in the performance of unmotivated discharges over time was noted, which was associated with the improvement of implantable cardioverter-defibrillators. The operating time for implantation of subcutaneous cardioverter-defibrillators was significantly less compared to transvenous cardioverter-defibrillators. Subcutaneous cardioverter-defibrillators were associated with a lower incidence of perioperative complications and high efficacy of shock therapy. Subcutaneous cardioverter-defibrillators were as effective as transvenous implantable cardioverter-defibrillators and did not have the risk of complications associated with implantation of endocardial electrodes. The main limitations of the technique were the impossibility of pacing and the absence of antitachycardic stimulation.

Subcutaneous ICD therapy results in a similar quality of life compared with transvenous ICD therapy during both short- and long-term follow-up

Abstract Funding Acknowledgements Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Boston Scientific Medical device company St. Paul, Minnesota, USA Introduction The PRAETORIAN trial showed that the subcutaneous implantable cardioverter defibrillator (S-ICD) is noninferior to the transvenous ICD (TV-ICD) with respect to device-related complications and inappropriate shocks in a conventional ICD population. It is unknown whether there is a difference in quality of life (QoL) between the two patient groups. The generator size and implant location differ between both devices. This may cause a variation in mental health status and pain perception between treatment arms, in particular in older patients, patients with low BMI, and females. Purpose This prespecified analysis of the PRAETORIAN trial compares the impact of the S-ICD and TV-ICD on QoL. Methods In the PRAETORIAN trial, 849 patients were randomised to S-ICD (n=426) or TV-ICD (n=423) therapy. QoL was prospectively measured at baseline, discharge and 12 and 30 months after ICD implant, by measuring cardiac-specific physical functioning with the Duke Activity Status Index (DASI) and psychological and physical well-being with the 36-Item Short Form Health Survey (SF-36, divided in 8 subscales). Patients who completed the questionnaires at baseline were included in this analysis. At each time point the mean change in score from baseline was calculated. Subgroups were made based on age (tertiles, &amp;lt; 58, 58-67 and &amp;gt;67 years), BMI categories (&amp;lt;25, 25-30, and ≥30 kg/m2) and sex. In these subgroups, we only looked at differences in pain and mental health between arms. Treatment effects, 95% CIs and interactions were calculated by regression models. Results A total of 823/849 patients completed the QoL questionnaires at baseline. Questionnaires were also completed by these patients at discharge (92%), 12 months (85%) and 30 months (69%). There was no difference in QoL between the arms at any time point (p&amp;gt;0.05, figure). Age, BMI and sex were not associated with a difference between the arms in SF-36 subscale bodily pain (p=0.73, 0.72 and 0.92 respectively), or SF-36 subscale mental health (p=0.15, 0.39 and 0.76) at 30 months. Similar results were seen at discharge and 12 months. Conclusion There were no differences in QoL between S-ICD and TV-ICD treatment in the first 30 months after implant. In addition, no differences in pain and mental health were seen in older patients, patients with low BMI and females. These results confirm that the S-ICD is a good alternative for the TV-ICD.

Evolution of surface and endocavitary signals in patients with arrhythmogenic cardiomyopathy at 1 and 5 years

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Small fee from Boston Scientific. Background The use of subcutaneous defibrillator (S-ICD) is a viable alternative to transvenous ICD in patients with Arrhythmogenic Cardiomyopathy (ACM). In transvenous ICD recipients low sensing values may exist at the time of implantation and a progressive decline of signal amplitude may occur later on due to the progressive myocardial fibrofatty replacement. Similarly to what happens at the intracavitary level, in patients with ACM there is a progressive modification of the surface ECG over time. Data on the impact of ECG evolution on S-ICD sensing are still lacking, particularly for different ACM phenotypes. Purpose This study aims to analyze the evolution of surface electrocardiogram (ECG), focusing on R-wave amplitude variation, and intracavitary electrograms (EGMs) in ACM different phenotypes during a 1-year and a 5 five-year follow-up. Methods This study is a retrospective analysis of the data of consecutive patients with ACM who were referred to our centre from January 1992 to October 2021. Using a dedicated software, the ECG analysis was performed in 7 leads: DI, DII, aVF (in view of the similar orientation with the three S-ICD vectors) and V1, V2, V3 and V5. Results We included 69 ACM patients: 28 patients (41%) had a right ventricular involvement (ARVC), 19 (27%) had a dominant LV involvement (ALVC) and 22 (32%) had biventricular involvement. 58 patients (84%) were ICD recipients; 45/58 patients (78%) had a transvenous ICD, and 13/58 (22%) had an S-ICD. During 5-year follow-up, in the whole ACM population, there were no significant changes in the amplitude of the R-wave, S-wave and T-wave. Phenotypic subgroups showed a different R-wave amplitude at baseline: biventricular ACM and ALVC patients had a lower R-wave amplitude in DII (p=0.04; p=0.05) and aVF (p=0.01; p=0.01) compared to ARVC patients. However, within each group, no difference was observed in R-wave amplitude at 1 and 5 years compared to baseline ECG (Figure 1). In the transvenous ICD recipients (45/69 patients) mean sensing decreased progressively over time (9,38 ± 4,24 mV at baseline, 7,70 ± 2,91 mV at 1 year, 1,85 ± 6,86 mV at 5 years). The reduction was not statistically significant at the first year of follow-up (p=0.239) but it reached significance at 5 years (p&amp;lt;0.001). Patients with biventricular ACM had lower sensing values at baseline than ARVC and ALVC (p&amp;lt;0,001). Sensing values in the biventricular patients did not decrease significantly during the 5-year follow-up (p=0.21), whereas in the ARVC and ALVC groups a reduction in sensing values was observed albeit not statistically significant in ALVC (p=0.01 in ARVC and p =0.06 in ALVC) (Figure2). Conclusions These data suggest that surface ECG may be more stable over time compared to EGM, therefore if a patient is suitable for S-ICD implantation S-ICD sensing may remain stable over time. Despite these findings, further studies are needed to support these hypotheses.

Transvenous vs. subcutaneous ICDs after transvenous device complication

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Boston Scientific Background During long-term follow-up of patients with implantable cardioverter defibrillators (ICD) numerous problems may occur. Apart from lead failure cardiac device related infectious endocarditis poses a serious threat to the patient. To date, there is no data on the question whether a re-implantation of a transvenous ICD (tv-ICD) or the implantation of a subcutaneous ICD (S-ICD) might be the better choice. Methods and Results The present study represents a single-center experience of matched patients with a complication of tv-ICDs which had to be revised. The patient either received a tv- or an S-ICD thereafter. 103 patients (53 patients in each group) were included, follow-up duration was about 3 years in both groups. Patients from the tv-ICD group were slightly older (58 vs 52 years). Infections as well as oversensing were equally responsible for revision in both groups (infection: tv 49%, S-ICD 45%, oversensing: tv 51%, S-ICD 45%). During follow-up unscheduled re-hospitalization (tv 60 %, S-ICD: 38%), re-infection (tv 9.4% vs. S-ICD 1.9%) and re-revision (tv: 18.9% vs S-ICD 5.7%) were all significantly more often in the tv-ICD group. Conclusion ICD patients who experienced a prior complication of a tv-ICD are at a considerable risk for a repeated complication if a new tv-ICD is implanted. Complication rates of S-ICDs in these patients seem to be lower so that S-ICD implantation might be preferred. Larger trials and prospective data is mandatory.

Long term longevity of defibrillator leads: a prospective follow-up over 25 years

Abstract Funding Acknowledgements Type of funding sources: None. Background The implantable cardioverter defibrillator (ICD) lead is the most fragile part of the device. Several studies have focused on both the longevity of ICD and the factors associated with lead malfunction but long-term data (i.e., ≥ 10 years) are limited. Purpose We report our experience on the very long-term longevity of ICD leads. Methods Data from all patients ≥18 years implanted with an transvenous ICD at our university hospital between 1988 and May 2021 were prospectively collected and analyzed. Follow-up was censored in July 2022. Data included patient characteristics, lead characteristics and follow-up data. The primary endpoint of the study was the survival rate without lead failure defined by the 2017 HR consensus . Factors influencing longevity were analyzed. Results 2093 ICD leads were included in our study. During follow-up (mean = 72.6±56.9 months, range = 11-299), there were 84 lead dysfunction. Lead survival rate was 97% at 5 years, 92% at 10 years, 88% at 15 years and 85% at 24 years respectively. In the multivariate analysis, factors associated with a higher risk of lead dysfunction revealed were: younger age (p = 0.001), channelopathy (p = 0.037), Linox leads (p = 0.041), Riata leads (p = 0.022) and Fidelis leads (p = 0.001). On the other hand, polyurethane coated leads (p &amp;lt; 0.001), Durata leads (p = 0.036), Endotak reliance leads (p = 0.016) and Sprint quattro 6935 leads (p = 0.026) were associated with less lead dysfunction. Conclusion The survival rate of the leads decreased progressively between 1 and 24 years after implantation but the risk of lead rupture seems to be maximal within the first 10 years after implant with little increase thereafter.