Transvenous ICD Systems Research Articles

Practical guidance for the implantation of non-transvenous ICD systems

As an alternative to transvenous ICD systems, two non-transvenous ICD systems have been established in recent years: The subcutaneous ICD (S-ICD), which has been established for several years, has apresternal electrode that is implanted subcutaneously and offers ashock function and, to alimited extent, post-shock pacing. In addition, the extravascular ICD (EV-ICD) has been available in Europe since 2023 which does not require transvenous electrodes and offers the option of providing patients with antibradycardic and antitachycardic stimulation in combination with aconventional ICD function. The lead of this device is implanted substernally. Initial implantation results are promising in terms of safety and effectiveness. Both systems avoid possible complications of transvenous electrodes. This article provides practical guidance for the implantation technique and possible complications.

Comparison of infection and complication rates associated with transvenous vs. subcutaneous defibrillators in patients with stage 4 chronic kidney disease: a multicenter long-term retrospective follow-up.

Patients with progressive chronic kidney disease (CKD) are at higher risk of infections and complications from cardiac implantable electronic devices (CIED). In patients with a primary or secondary prophylactic indication, implantable cardiac defibrillators (ICD) can prevent sudden cardiac deaths (SCD). We retrospectively compared transvenous-ICD (TV-ICD) and intermuscularly implanted subcutaneous-ICD (S-ICD) associated infections and complication rates together with hospitalizations in recipients with stage 4 kidney disease. We retrospectively analyzed 70 patients from six German centers with stage 4 CKD who received either a prophylactic TV-ICD with a single right ventricular lead, 49 patients, or a S-ICD, 21 patients. Follow-Ups (FU) were performed bi-annually. The TV-ICD patients were significantly older. This group had more patients with a history of atrial arrhythmias and more were prescribed anti-arrhythmic medication compared with the S-ICD group. There were no significant differences for other baseline characteristics. The median and interquartile range of FU durations were 55.2 (57.6-69.3) months. During FU, patients with a TV-ICD system experienced significantly more device associated infections (n = 8, 16.3% vs. n = 0; p < 0.05), device-associated complications (n = 13, 26.5% vs. n = 1, 4.8%; p < 0.05) and device associated hospitalizations (n = 10, 20.4% vs. n = 1, 4.8%; p < 0.05). In this long-term FU of patients with stage 4 CKD and an indication for a prophylactic ICD, the S-ICD was associated with significantly fewer device associated infections, complications and hospitalizations compared with TV-ICDs.

Subcutaneous Implantable Cardioverter-defibrillator in Preventing Ventricular Arrhythmia and Sudden Cardiac Death – A Single-center Experience

Abstract Introduction: Subcutaneous implantable cardioverter-defibrillator (S-ICD) differs from the transvenous ICD (TV-ICD) system in its extrathoracic and extravascular localization, eliminating the risks arising from vascular access and leading to fewer complications. The objective was to describe the functionality and postoperative complications associated with SICD implants in patients with cardiac dysfunctions. Methods: We enrolled six patients eligible for SICD due to either anterior wall myocardial infarction or left ventricular dysfunction, who reported to our tertiary cardiac care center from June 2020 to March 2022. Preprocedural evaluation for various cardiac parameters was carried out. The procedure was performed under antibiotic prophylaxis. Two incision techniques were used for the SICD placement. The primary and secondary endpoints for the cases were set to evaluate device-related complications and predictive outcomes, respectively. Results: Subcutaneous implantable defibrillator was placed in six male patients aged 36−51 years. The procedure demonstrated an efficient, reliable, and well-accepted modality in eliminating ventricular tachycardia, ventricular fibrillation, and sudden cardiac death. In addition, postoperative complications, such as device infection, pocket hematoma, blood transfusion, prolonged hospitalization, cardiac perforation or tamponade, lead repositioning, or inappropriate shocks, were not reported in the 2 years of follow-up. Conclusion: Subcutaneous implantable defibrillator promises to offer a suitable and safer option for TV-ICD, especially in young patients. It circumvents the need to enter the vasculature or cardiac chambers. As a result, fewer reported lead-related complications, better cosmetic appearance, and greater immediate postoperative comfort as it permits free shoulder movement.

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.

PO-05-052 COMPARISON OF SIMULTANEOUS, MATCHED PROGRAMMING AMBULATORY RHYTHM DETECTION BETWEEN A NOVEL EXTRAVASCULAR AND STANDARD TRANSVENOUS ICD SYSTEMS

A novel extravascular (EV) ICD lead (AtaCor Medical, San Clemente, CA) is under development for sensing and defibrillation of ventricular tachyarrhythmias (VF) using commercial DF-4 compatible ICD pulse generators (PG). The purpose of this analysis is to perform a within-patient comparison of sensing and detection of ambulatory spontaneous cardiac rhythms between a novel EV-ICD system and a simultaneously implanted standard transvenous (TV) ICD system. In the non-randomized, single-center SECURE EV Study (NCT05099289), human subjects (n=18) were implanted with two ICD systems: (1) the Research EV-ICD system and (2) a standard TV-ICD system. The Research EV-ICD Lead was implanted into the anterior mediastinum and fixated at the fascial plane along the left parasternum. The EV-ICD lead was then tunneled subcutaneously to a left lateral pocket. The TV-ICD was implanted in standard fashion along the left or right subclavian with endocardial lead placement. The ICD pulse generators were programmed with matched sensitivity, detection zones and discrimination features to compare appropriate and inappropriate ambulatory sensing function. The EV-ICD systems were implanted for up to 90-days and were left in a “recording only” mode to store events without therapy delivery. Each implant system was interrogated over the 90- day study period to compare adjudicated stored events between the two systems. Matched and unmatched stored electrograms of appropriate and inappropriate episodes were valuated. The prototype EV-ICD lead placement was successful in 16/18 (89%) subjects. The median follow-up duration for the EV ICD lead was 90 days (mean = 71 days). During the follow up, spontaneous tachycardia events were stored in 7 (44%) subjects (2 patients with 3 matched appropriate events (Figure 1) and 5 patients with matched and unmatched inappropriate events). Two EV ICD subjects had unmatched inappropriate sensing events due to noise caused by a broken anode cable and another due to oversensing diaphragm myopotentials not seen by the TV ICD. Early experience with a prototype left, anterior parasternal EV ICD lead is highly correlative in automatically sensing and detecting cardiac rhythms such as VF using commercially available ICD PGs. Further iterations of the EV ICD lead should improve specificity.

Subcutaneous Implantable Cardioverter-defibrillator Explantation-A Single Tertiary Center Experience.

The subcutaneous implantable cardioverter-defibrillator (S-ICD) is an appealing alternative to transvenous ICD systems. However, data on indications for S-ICD explantations are sparse. The objective of this study was to assess the incidence and indications for S-ICD explantation at a large tertiary referral center. We conducted a retrospective study of all S-ICD explantations performed from 2014–2020. Data on demographics, comorbidities, implantation characteristics, and indications for explantation were collected. A total of 64 patients underwent S-ICD explantation during the study period. During that time, there were 410 S-ICD implantations at our institution, of which 53 (12.9%) were explanted with a mean duration from implant to explant of 19.7 ± 20.1 months. The mean age of the patients at explantation was 44.8 ± 15.3 years, and 42% (n = 27) were women. The indication for S-ICD implantation was primary prevention in 58% and secondary prevention in 42% of patients, respectively. The most common reason for explantation was infection (32.8%), followed by abnormal sensing (25%) and the need for pacing (18.8%). Those who underwent S-ICD explantation for pacing indications were significantly older (55.7 ± 13.6 vs. 42.3 ± 14.6 years, P = 0.005) with a wider QRS duration (111 ± 19 vs. 98 ± 19 ms, P = 0.03) at device implantation compared to patients who underwent explantation for other indications. The incidence of S-ICD explantation in a large tertiary practice was 12.9%. While infection was the indication for one-third of the explantations, a significant number of explantations were due to sensing abnormalities and the need for pacing. These data may have implications for patient selection for S-ICD implantation.

Non-traditional implantable cardioverter-defibrillator configurations and insertion techniques: a review of contemporary options.

Implantable cardioverter-defibrillators (ICDs) have revolutionized the treatment of acquired or inherited cardiac diseases associated with a high risk of sudden cardiac death due to ventricular tachyarrhythmias. Contemporary ICD devices offer reliable arrhythmia detection and discrimination algorithms and deliver highly efficient tachytherapies. Percutaneously inserted transvenous defibrillator coils with pectoral generator placement are the first-line approach in the majority of adults due to their extensively documented clinical benefit and efficiency with comparably low periprocedural implantation risks as well as the option of providing pain-free tachycardia treatment via anti-tachycardia pacing (ATP), concomitant bradycardiaprotection, and incorporation in a cardiac resynchronization therapy if indicated. Yet, expanding ICD indications particularly among younger and more complex patient groups as well as the increasingly evident long-term consequences and complications associated with intravascular lead placements promoted the development of alternative ICD configurations. Most established in daily clinical practice is the subcutaneous ICD but other innovative extravascular approaches like epicardial, pericardial, extra-pleural, and most recently substernal defibrillator coil placements have been introduced as well to overcome shortcomings associated with traditional devices and allow for individualized treatment strategies tailored to the patients characteristics and needs. The review aims to provide practical solutions for common complications encountered with transvenous ICD systems including restricted venous access, high defibrillation/fibrillation thresholds (DFTs), and recurrent device infections. We summarize the contemporary options for non-traditional extravascular ICD configurations outlining indications, advantages, and disadvantages.

Comparative Study between Subcutaneous and Endovascular Defibrillator Recipients Regarding Tolerance to the Implant Procedure and Perception of Quality of Life.

ResumoFundamentoO cardioversor-desfibrilador implantável subcutâneo (S-CDI) é uma alternativa segura ao sistema convencional do CDI transvenoso (TV-CDI) para evitar morte súbita.ObjetivoComparar o impacto do tipo de sistema de CDI e técnica cirúrgica na qualidade de vida dos pacientes, bem como a gravidade do desconforto e da dor, entre receptores de S-CDI e TV-CDI.MétodosPacientes consecutivamente implantados com um sistema S-CDI foram pareados com pacientes com um sistema TV-CDI. Além disso, foram incluídos os pacientes submetidos ao implante de S-CDI após a remoção de um TV-CDI, devido a complicações. Foram avaliadas a qualidade de vida (medida com o questionário de saúde de 12 itens) e a gravidade da dor e desconforto. Significância estatística foi definida como p < 0,05.ResultadosForam analisados 64 pacientes implantados com S-CDI ou TV-CDI sob anestesia local e sedação consciente. Pacientes com sistemas S-CDI e TV-CDI não diferiram significativamente nos escores de qualidade de vida. Os pacientes com S-CDI apresentaram maior nível de dor peri-operatória; nenhuma diferença foi encontrada em relação à gravidade da dor intra-operatória. A magnitude do desconforto estético e dos distúrbios do sono não diferiu entre os grupos.O S-CDI foi implantado em 7 pacientes adicionais após a remoção de um TV-CDI. Todos exceto um desses pacientes recomendaram o sistema S-CDI.ConclusõesO tipo de sistema de CDI e a técnica cirúrgica têm impacto insignificante na qualidade de vida dos pacientes. Estes resultados sugerem que a sedação consciente, fornecida por uma equipe experiente de eletrofisiologia, pode ser considerada uma alternativa à anestesia geral para o manejo de pacientes submetidos ao implante de S-CDI.

A novel screening tool to unmask potential interference between S-ICD and left ventricular assist device.

In patients with a left ventricular assist device (LVAD), the subcutaneous implantable cardioverter-defibrillator (S-ICD) can be an alternative to transvenous ICD systems due to reduced risk of systemic infection, which could lead to extraction of the ICD as well as the LVAD. S-ICD eligibility is lower in patients with LVAD than in patients with end-stage heart failure without LVAD. Several reports have shown inappropriate S-ICD therapy in the coexistence of LVAD and S-ICD. The aim of the present study was to evaluate S-ICD eligibility in patients with LVAD using the established electrocardiogram (ECG)-based screening test as well as a novel device-based screening test to identify potentially inappropriate S-ICD sensing in this specific patient cohort. The present study included 115 patients implanted with an LVAD. The standard ECG-based screening test and a novel device-based screening test were performed in all patients. Eighty patients (70%) were eligible for S-ICD therapy with the standard ECG-based screening test. Performance of the novel device-based screening test identified device-device interference in 14 of these 80 patients (12%). Using a novel extended device-based S-ICD screening method, a small number of patients with LVAD deemed eligible for S-ICD with the standard ECG-based screening test exhibit device-device interference. Careful S-ICD screening should be performed in patients with LVAD, who are candidates for S-ICD therapy, to prevent inappropriate sensing or ICD therapy.

P3450Safety and feasibility of implanting trans-venous ICD system in left axilla: compare to conventional ICD implantation site

P3450Safety and feasibility of implanting trans-venous ICD system in left axilla: compare to conventional ICD implantation site

Long-term single-center experience of defibrillator therapy in children and adolescents

BackgroundImplantable cardioverter-defibrillator (ICD) systems are established therapy for prevention of sudden cardiac death. Long-term data on ICD systems in children and adolescents is rare. The present study displays a long-term single-center follow-up of children and adolescents with ICD systems. Methods and resultsThe present study represents a single-center experience of patients younger than 18 years who received an ICD (n = 58). Follow-up data included in-house follow-up as well as examinations of collaborating specialists. Mean age at implantation was 14.0 ± 3.3 years and 33 patients (56.9%) were male. A transvenous ICD system was implanted in 54 patients (93.1%). In 33 patients (56.9%) electrical heart disease or idiopathic ventricular fibrillation represented the underlying condition of ICD implantation. Median follow-up duration was 70 months (45; 94). 3 patients (5.2%) died during the observation period. None of these deaths was associated with ICD failure. Appropriate shocks occurred in 32 patients (55.2%). Inappropriate shock delivery was recorded in 17 patients (29.3%). Supraventricular tachycardia represented the most frequent cause of inappropriate shock delivery (9 patients, 52.9%). T-wave oversensing led to inappropriate shock delivery in 3 patients (17.6%). In 5 patients (29.4%), lead failure caused inappropriate shock delivery. Of note, during follow-up lead failure was reported in 15 patients (25.9%) leading to surgical revision. ConclusionICD therapy in children and adolescents is effective for prevention of sudden cardiac death. The rate of appropriate shock deliveries was significantly higher as compared with large ICD trials. Inappropriate therapies occurred frequently. In particular supraventricular tachycardia, T-wave oversensing and lead failures were responsible for these episodes.

Selecting the right defibrillator in the younger patient: Transvenous, epicardial or subcutaneous?

The advent of the subcutaneous implantable cardioverter-defibrillator (SQ-ICD) provides an alternative to transvenous and epicardial ICD therapy. Particularly germane to the young patient with congenital heart disease or inheritable arrhythmia syndromes, the SQ-ICD may be ideal for those who do not require permanent cardiac pacing. The serious complications associated with transvenous ICD systems are largely driven by the intravascular components of these devices and are avoided by this extravascular technique. Multiple clinical trials have shown that SQ-ICDs are effective in detecting and terminating ventricular arrhythmias, yet nuanced issues must be considered, especially in the context of congenital cardiovascular anomalies. This review aims to contextualize the role of this technology in contrast with traditional ICDs, and provide a logical approach to appropriate device selection.

Subcutaneous Implantable Cardioverter Defibrillators Implantation Without Defibrillation Threshold Testing: A Single Center Experience

BackgroundSubcutaneous implantable cardioverter defibrillator (S-ICD) system has been proven to be an effective therapy for prevention of sudden cardiac death (SCD) in selected patients. Although the Shockless IMPLant Evaluation (SIMPLE) trial has shown that defibrillation threshold (DFT) testing is not necessary for transvenous ICD (TV-ICD) systems, it is still recommended for S-ICD systems. We aimed to study the efficacy and safety of S-ICD implantation without DFT in our Heart Center with the comparison of S-ICD patients’ outcome to those with a single chamber TV-ICD without DFT in the same period.MethodsA retrospective analysis of patients underwent S-ICD without DFT from December 2014 to May 2016 with the comparison to single chamber TV-ICD patients implanted during the same period.ResultsThirty consecutive patients (23 males (76.7%); mean age 41 ± 13 years; mean left ventricular ejection fraction 30±12%) received a S-ICD for primary (25 patients, 83.3%) or secondary prevention (five patients, 16.7%) of SCD. During a mean follow-up of 710.6 ± 190 days, three patients received 38 appropriate ICD shocks (90.5%), and two patients received four inappropriate shocks (9.5%). There were two mortalities (6.7%): one cardiac and one non-cardiac. When compared to 30 consecutive who received a single chamber TV-ICD during the same period, there was no significant difference in mortality.ConclusionsImplantation of S-ICD using intermuscular approach without DFT seems to be safe and effective. Data from large S-ICD registries with long-term follow-up, and preferably randomized controlled studies, are needed to confirm this finding.

The Subcutaneous Implantable Cardioverter Defibrillator.

The subcutaneous implantable cardioverter defibrillator (S-ICD) is a subcutaneous alternative to conventional transvenous ICD (TV-ICD) systems, which have previously been shown to treat life-threatening ventricular tachyarrhythmias in cardiac disease patients. A review of the literature reveals that S-ICDs have similar shock efficacy rates for both induced and spontaneous ventricular tachyarrhythmias when compared with TV-ICDs. Furthermore, S-ICDs seem to have a higher specificity for withholding therapy when supraventricular tachycardia is present compared with TV-ICDs. The advantages of the S-ICD system are numerous: fewer vascular complications including thrombosis and hemothorax, avoidance of fluoroscopy, and an easier means of lead replacement. These advantages make the S-ICD system most suitable for younger patients who may require replacements in later life, those with abnormal venous anatomy, and individuals prone to infection and/or central vein thrombosis. However, S-ICDs are not without their complications and are associated with a higher incidence of inappropriate shocks secondary to T wave oversensing. S-ICDs also lack antitachycardia pacing, making them a suboptimal device in patients with recurrent monomorphic ventricular tachycardia who would otherwise benefit from the antitachycardia pacing offered in TV-ICDs. Lastly, the limited number of long-term randomized, head-to-head studies involving direct comparison with TV-ICDs poses a challenge in the implementation of the S-ICD.

Longevity of the Subcutaneous Implantable Defibrillator: Long-Term Follow-Up of the European Regulatory Trial Cohort.

The recent advent of subcutaneous implantable cardioverter defibrillators (S-ICDs) has provided investigators with a safe and effective new therapy in patients at risk of sudden cardiac death. At present, no data are available with regard to the longevity of these new devices. This study evaluated the longevity of the S-ICD system. All patients enrolled in the European Regulatory Trial were included in the analysis. During follow-up, time and causes of device replacement or explantation were assessed and categorized. Device longevity was estimated using Kaplan-Meier analysis. Fifty-five patients were followed for a median of 5.8 years. During follow-up, 26 (47%) patients underwent device replacement and 5 (9%) underwent device explantation. Median time to replacement was 5.0 years (Q1-Q3, 4.4-5.6 years). Replacement was caused by battery depletion in 25 patients (92%), of which 5 within 1.5 years because of premature battery depletion, and by infection in 1 patient (2%). Replacement for a transvenous ICD system was required in 4 patients (7%) because of ineffective defibrillation in 1 (0.003 per patient-year), need for resynchronization therapy in 2 (0.01 per patient-year), and for antibradycardia pacing in 1 (0.003 per patient-year). At 5 years follow-up, 71% of devices were still in service. This study provides the first estimate of S-ICD system longevity since its introduction in clinical practice. Median longevity of the first generation S-ICD system was 5.0 years. The majority of devices were replaced because of battery depletion. URL: http://www.clinicaltrials.gov. Unique identifier: NCT01117792.

Clinical experience with subcutaneous implantable cardioverter-defibrillators.

The subcutaneous implantable cardioverter-defibrillator (S-ICD) is a novel technology for the treatment of sudden cardiac death. The system consists of a pulse generator implanted in the left axillary position and a single subcutaneous lead for detection and delivery of therapy. Initial clinical trials of S-ICDs demonstrated improved safety and efficacy when compared to transvenous ICD systems, leading to their widespread approval. The main advantage of the S-ICD is the avoidance of vascular access and the complications associated with transvenous leads. Owing to limitations of S-ICDs, patients who require pacing support or antitachycardia pacing are not candidates for the device; instead, this system is currently used most commonly in young patients with previous lead malfunction, limited vascular access, or low risk for subsequent bradycardia or antitachycardia pacing. Findings from device trials support S-ICDs as a viable alternative to transvenous ICDs in certain patients, and the current limitations associated with S-ICDs are likely to be addressed in future iterations of the device, extending its indications and target patient populations.

Subcutaneous implantable-defibrillator is better to be a “collaborator” rather than a “replacement”

In order to avoid intravascular lead complications, the totally subcutaneous implantable-defibrillator (S-ICD) has been developed to replace the conventional transvenous ICD system (T-ICD). This novel device, developed and tested over the past decade, gained approval as accepted therapy for detection and termination of ventricular arrhythmias. The advantages of this nontransvenous ICD system are obvious, including elimination of complications related to venous access, no physical stress on leads associated with cardiac motion, less morbidity associated with device extraction and a potential reduction in endovascular infection risk [1].

Worldwide experience with a totally subcutaneous implantable defibrillator: early results from the EFFORTLESS S-ICD Registry

AimsThe totally subcutaneous implantable-defibrillator (S-ICD) is a new alternative to the conventional transvenous ICD system to minimize intravascular lead complications. There are limited data describing the long-term performance of the S-ICD. This paper presents the first large international patient population collected as part of the EFFORTLESS S-ICD Registry.Methods and resultsThe EFFORTLESS S-ICD Registry is a non-randomized, standard of care, multicentre Registry designed to collect long-term, system-related, clinical, and patient reported outcome data from S-ICD implanted patients since June 2009. Follow-up data are systematically collected over 60-month post-implant including Quality of Life. The study population of 472 patients of which 241 (51%) were enrolled prospectively has a mean follow-up duration of 558 days (range 13–1342 days, median 498 days), 72% male, mean age of 49 ± 18 years (range 9–88 years), 42% mean left ventricular ejection fraction. Complication-free rates were 97 and 94%, at 30 and 360 days, respectively. Three hundred and seventeen spontaneous episodes were recorded in 85 patients during the follow-up period. Of these episodes, 169 (53%) received therapy, 93 being for Ventricular Tachycardia/Fibrillation (VT/VF). One patient died of recurrent VF and severe bradycardia. Regarding discrete VT/VF episodes, first shock conversion efficacy was 88% with 100% overall successful clinical conversion after a maximum of five shocks. The 360-day inappropriate shock rate was 7% with the vast majority occurring for oversensing (62/73 episodes), primarily of cardiac signals (94% of oversensed episodes).ConclusionThe first large cohort of real-world data from an International patient S-ICD population demonstrates appropriate system performance with clinical event rates and inappropriate shock rates comparable with those reported for conventional ICDs. Clinical trial registration URL: http://www.clinicaltrials.gov. Unique identifier NCT01085435.

Clinical Experience of Subcutaneous and Transvenous Implantable Cardioverter Defibrillators in Children and Teenagers

Subcutaneous implantable cardioverter defibrillator (S-ICD) systems have no components in contact with the heart and may avoid complications such as lead fracture, venous obstruction, or endocarditis that occur with transvenous leads. Concerns have been raised regarding inappropriate shocks and pocket erosion with S-ICD systems. We have compared the performance of S-ICD and transvenous ICD systems in children and teenagers. We studied consecutive patients <20 years of age who received an ICD over a 4-year period in two Scottish centers. Baseline characteristics, complications, and ICD therapy were recorded. The primary outcome measure was survival. The secondary outcome measure was survival-free from inappropriate ICD therapy or system revision. Nine S-ICD were implanted in nine patients. Eight transvenous ICD were implanted in six patients; two were redo procedures. Baseline characteristics were well matched. Median duration of follow-up was lower for S-ICD (20 months) than for transvenous ICD (36 months, P = 0.0262). Survival was 100% in both groups. Survival free of inappropriate therapy or system revision was 89% for S-ICD and 25% for transvenous ICD systems (log-rank test, P = 0.0237). No S-ICD were extracted, but three transvenous ICD were extracted due to infection (n = 1) and lead failure (n = 2). In real-world use in children and teenagers, S-ICD may offer similar survival benefit to transvenous ICD, with a lower incidence of complications requiring reoperation. In the absence of randomized trials, S-ICD should be compared prospectively with transvenous ICD in large multicenter registries with comparable periods of follow-up.

Gegenwärtiger Stand und Probleme vollständig subkutaner ICD-Systeme (S-ICD®)

Prevention of sudden cardiac death is one of the most important tasks of cardiology. Transvenous ICD-systems have impressively proven their effectiveness in numerous randomized trials. Transvenous systems have their limitations due to frequent long-term lead complications. Having been available for a few years, the entirely subcutaneous ICD-system (S-ICD®, Boston Scientific, USA, former Cameron Health, USA) seems to be a promising alternative despite the lack of prospective data. The implantation of the SICD® can be performed easily; lead complications are rare because of the totally subcutaneous implantation. The detection and therapy of life-threatening tachyarrhythmias seems to be safe, although inappropriate therapies are a common problem in cases of insufficient ECG screening. S-ICD® is no alternative to the transvenous system due to limited programming options and the lack of stimulation, but it is an interesting supplement of ICD therapy.