Implantable Cardioverter Defibrillator System Research Articles

Lead and generator dysfunction in children and adolescents with epicardial pacemaker and implantable cardioverter defibrillator systems: The challenge of early recognition.

A major issue of cardiac implantable electronic device therapy in pediatric patients is the high incidence of lead dysfunctions and associated reinterventions. This study aims to analyze the timing and mode of generator and lead dysfunction. Retrospective single-center analysis of 283 children and young adults with an epicardial pacemaker or implantable cardioverter defibrillator therapy from 1998 to 2018. Mean age at implant was 6.1 years (SD±5.8 years) and median follow-up 6.4 years (IQR, 3.4-10.4 years) with a total of 1998.1 patient-years of cardiac device therapy. A total of 120 lead-related complications were observed in 82 patients (29.0%). They were detected by device interrogation (n=86), symptoms (n=13), intraoperative findings (n=7), routine chest radiography (n=5), routine ECG (n=4), patient alert sound by device (n=3), and physical examination (n=2). It was possible to find the date of the event on the device memory in 21 out of 120 lead dysfunctions (18%) with a median time interval between occurrence and detection of 1.3 months (IQR, 0.2-5.0 months). Moreover, 20 generator-related complications were found in 13 patients. Early recognition of lead and generator dysfunction remains challenging in pediatric patients. As symptoms are relatively rare conditions in the context of PM and ICD dysfunction, close patient monitoring is mandatory, even in asymptomatic patients with a good clinical course. To further improve the safety of pediatric pacing systems, more durable epicardial electrodes are desirable.

Wearable cardioverter defibrillator after ICD-system explantation: data from a multicenter registry

Abstract Background Data on the use of wearable cardioverter defibrillator (WCD) among patients after cardiac implantable electronic device explantation of 1- to 3-chamber Implantable Cardioverter-defibrillator system (ICD) are sparse. Subsequently several guidelines give a different recommendation regarding WCD indication in this cohort. Objectives We aimed to study the baseline characteristics and outcome of patients treated with WCD after ICD explantation. The primary outcome is appropriate WCD shock. Methods 1104 patients were included in a multicenter registry from seven European centers. Among this cohort 109 patients received a WCD to bridge the time after ICD-system explantation until reimplantation due to a persistent ICD-indication. The mean follow-up time of the whole cohort was 824±773 days. Cardiovascular history and non-cardiovascular morbidities were evaluated. In addition, the presence of ventricular tachyarrhythmias and/or WCD shocks was evaluated in the explantation group. Furthermore, after ICD-reimplantation the rate of rehospitalization for ventricular tachyarrhythmias, atrial fibrillation, stroke and congestive heart failure was followed. Results In the explantation group patients were older (65±14 versus 59±15; p<0.001) and were hospitalized longer (21±15 days versus 14±12 days; p<0.001). The index LVEF differed significantly (35.7±14.1% versus 29.3±11.5%; p<0.001). The LVEF value did not differ significantly over short-term follow-up (35.7±14.2% versus 37.9±11.9%; p=0.204). Wear days among patients after ICD-system explantation were 61±46 days. An appropriate WCD shock was documented in 7.3% after ICD-system explantation during WCD use. Up to 80.6% of patients after ICD-system explantation received a reimplantation. The rate of rehospitalization due to ventricular tachyarrhythmias was 7.3%, due to heart failure 6.8% and due to atrial fibrillation 4.1%. After ICD-implantation the rate of appropriate shocks was 12/89 (13.4%). In the multivariable regression analysis myocarditis and ICD-system explantation were positive predictors for the risk of ventricular tachyarrhythmias, but nevertheless an improved left ventricular ejection fraction (LVEF) and use of aldosterone antagonists were negative predictors for the risk of ventricular tachyarrhythmias. Conclusions Cccurrence of malignant arrythmia after ICD-system explantation is high and the use of WCD among these patients could be beneficial in preventing sudden cardiac death.

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)

A 25-year single-center experience with transvenous and subcutaneous ICD patients under thirty years of age

Abstract Funding Acknowledgements Type of funding sources: None. Background Young implantable cardioverter-defibrillator (ICD) recipients present high rate of inappropriate shocks and complications. Some of them seem to be underestimated. The subcutaneous ICD(S-ICD) system was developed to eliminate lead-related complications and was proved to be effective, avoiding intracardiac and endovascular adhesions. Aims To report on our clinical experience with transvenous (TV-ICD) and S-ICD therapy in patients under thirty years of age. Methods We reviewed database of ICD recipients in our institution between 1996 and 2022(25 years) and have chosen 125 pts consecutively implanted up to and including the age of 30 years. We retrospectively analyzed the rate of appropriate(AI) and inappropriate interventions(IS), lead complications rate, infection rate, mortality and treatment options. Results The study group: 84 TV-ICD(age: 6-30, BMI: 16,3-22,2) and 41 S-ICD( age: 15-30, BMI; 15,6-31,1) patients. The mean follow-up in analyzed groups was 159±48 and 40± 2 months respectively. Abnormal ventricular function: EF≤30 occurred in compared groups: 12/84(14%) and 5/41(12%) respectively, p=0,3. 24/84pts(28%) received ≥1 AI for VT/VF(ATP or shock) in TV-ICD and 4/40pts(10%) in S-ICD groups. 25/84 pts(30%) received one or multiple (IS) and 1/40pts(2,5%) in compared groups respectively, p=0,02. There were 18/84 (21.5%) ventricular lead dysfunctions(reimplantation of a new system) in TV-ICD and 0% in S-ICD groups, p=0,025. An infection rate (endocarditis or device pocket )was 8/84 (10%) in TV-ICD group with complete system removal and 1 pts (2,5%) wound infection(staphylococcus aureus) in S-ICD group successfully treated with antibiotics. 1 left ventricular assist device was implanted in end-stage heart failure S-ICD patient with good result. There were 2 S-ICD implantations as a concomitant device i.e. conversion of TV-ICD(with therapy OFF) to S-ICD due to ventricular lead dysfunction. 4(10%) pts required generator elective replacement due to early battery depletion in S-ICD group. In 2(5%)pts right sternal lead location was chosen due to better sensing results. Mortality rate was 6/84 pts (7%), caused by ventricular lead dysfunction, end-stage heart failure or heart transplantation fatal result in TV-ICD group. There was no death in S-ICD group. Conclusions TV- ICD implantation in children and young adults is a feasible and effective procedure in a 25-year follow-up but the rate of complications is high in this population. S-ICD recipients did not experienced lead failures or systematic infections. S-ICD appears to be a good therapy option and an alternative to TV-ICD in pediatric and young patients population, preventing from some serious lead complications and tricuspid valve regurgitation. The method and follow-up period effect is present between the TV-ICD and S-ICD in analyzed groups.

Validation of a transthoracic impendance sensor for screening of sleep apnea in CIED patients: a pooled analysis of AIRLESS and UPGRADE

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Scientific grant support from the Boston Scientific Investigator Sponsored Research (ISR) Committee, Boston Scientific, St. Paul, MN, USA. Background/Introduction Cardiac implantable electronic devices and their integrated thoracic impedance sensors, meant to detect sleep apnea, are available for over a decade now. Despite its usage in daily clinical practice, there is only limited data on its diagnostic accuracy. Purpose To further validate an apnea sensor by using polysomnography (PSG) and investigate subgroups with potential differences in diagnostic accuracy. Methods AIRLESS and UPGRADE were prospective investigator driven trials meant to validate an apnea sensor. Patients, who either fulfilled the criteria for implantation of an implantable cardioverter-defibrillator (ICD), cardiac resynchronization therapy (CRT) or upgrading to CRT according to current guidelines were eligible for enrolment. Sleep apnea and its severity, measured by apnea-hypopnea index (AHI), were exclusively assessed by PSG. PSG was conducted in a time interval of 1 to 3 months post implantation of the device. For direct comparison, the apnea sensor derived respiratory disturbance index (RDI) was used from the identical night. Bivariate correlations (spearman coefficient) as well as the Bland-Altmann method were applied to assess diagnostic accuracy of the apnea sensor. Results Overall, 80 patients were analysed, out of whom the majority (n = 35, 43.8%) were diagnosed with central sleep apnea. Sixteen (20.0%) patients received a conventional ICD system, whereas 21 (26.3%) were implanted a CRT-P and 43 (53.8%) a CRT-D. Atrial fibrillation was known in 50.0% (n=40) of patients, 45 patients suffered from periodic leg movement syndrome (PLMS, 56.3%). In the overall cohort, the sensor derived RDI correlated significantly with the AHI (r = 0.61, p < 0.001) with a mean difference (MD) of -12.6 (95% CI -38.2 – 13.0). The sensor did specifically perform well in patients without atrial fibrillation (r = 0.80, p < 0.001; MD -9.0, 95% CI -30.4 – 12.5), while the presence of PLMS did not affect the accuracy of measurements (PLMS: r = 0.60, p = 0.007, MD -16.1, 95% CI -43.9 – 11.8 vs. no PLMS: r = 0.62, p = 0.001, MD -9.9, 95% CI -32.8 – 12.9). Furthermore, the RDI was found to correlate well in patients with central sleep apnea (r = 0.61, p = 0.013), although similar overestimation was observed (MD -11.6, 95% CI -35.4 – 12.2) as in other subgroups. Conclusion In an exclusive heart failure cohort, the apnea sensor did correlate well with the PSG derived AHI. Although similar correlation is found in most subgroups, there remains to be a decent overestimation of events.

PO-03-043 IMPLANTABLE CARDIOVERTER DEFIBRILLATOR THERAPY WITH LEFT BUNDLE AREA PACING DELIVERS HIGHLY SUCCESSFUL ANTITACHYCARDIA PACING THERAPY FOR VENTRICULAR TACHYCARDIA AND SUCCESSFUL DEFIBIRILLATION

Left bundle area pacing (LBAP) has emerged as a promising therapy for cardiac resynchronization. However, the effects of LBAP when used as the primary sensing and antitachycardia pacing lead for implantable cardioverter defibrillator (ICD) therapy is unknown. There are potential disadvantages of using a separate pace/sense lead as the defibrillator lead integrity alerts are not maintained and dislodgement may not be known. Additionally, DF1 leads add complexity and points of failure to an ICD system. Examine the outcomes of using a LBAP lead as the pace/sense lead in ICD therapy. A retrospective review of all patients with implanted LBAP leads for ICD therapy was performed. In all cases a DF1 defibrillator lead was used with the pace/sense portion capped and a LBAP lead used. All devices were Abbott (Ellipse, Fortify, Quadra assura). In some cases simultaneous LBAP and CS pacing was performed. Medtronic 3830 leads were used for LBAP. Outcomes included VT events, ATP, and defibrillator therapy. Programming was left ot operator discretion but when no prior history of VT was known a monitor rate of 170 and treatment rate of 200 was programmed. 65 patients were identified with 45 ICDs and 20 cardiac resynchronization therapy defibrillators (CRTDs) since January of 2020. The median follow up time was 13 months. There were 138 VT/VF episodes during the study period occuring in 10 patients. 7 episodes were adjudicated to be SVT and 2 led to inappropriate shocks (1.5%). VT cycle length was 317±31 ms (rate: 191±17 bpm) withATP was delivered in 126 episodes and successfully terminated 120 (95%) of episodes. Per patient success was 90% with an average 1.3 ATP attempts. 5 appopriate shocks were delivered with 100% success. ICD therapy with a LBAP pacing lead as the primary pace/sense lead delivers highly effective ATP and ICD therapy. The rate of successful ATP is significantly higher than previous studies of ATP which have generally ranged from 50-70%. There are several plausible reasons for this including a more rapid and synchronous depolarization of the ventricle rendering more of the ventricle refractory. The small number of shocks were successful. There were no lead dislodgements or issues with sensing. These findings merit further study into the role of LBAP for ICD and ATP therapy.

Acceptance of telemetric care for patients with sICD safety advice : Qualitative interview study in cardiological health services research

Telemonitoring is used to monitor implantable cardioverter defibrillators (ICDs). Despite the scientifically proven effectiveness and safety of telemetric care, studies show that the offer is not used and accepted by all patients. The aim of this study is to investigate the attitudes of ICD patients towards telemonitoring, including which aspects influence attitudes and decision-making. Data were collected using semi-structured, guideline-based individual interviews. Atotal of 14patients with asubcutaneous ICD (sICD) and both primary and secondary prophylactic indications were recruited. Data analysis followed acontent-structuring qualitative approach. Patients with telemonitoring perceived ahigh benefit with low concerns about digital technology, while the opposite was observed for patients without telemonitoring. The patients' previous medical experience has acrucial impact on the acceptance of telemonitoring. All age groups reported the technical implementation and practical handling of telemonitoring to be simple and uncomplicated. The results suggest that the primary and secondary prophylactic indication for ICD implantation have an influence on the attitude towards telemonitoring and, thus, on acceptance. Further qualitative research regarding user acceptance of telemonitoring of other ICD systems is needed.

Asymptomatic channelopathies : Risk stratification and primary prophylaxis

In general, asymptomatic patients with channelopathies are at increased risk of sudden cardiac death (SCD), due to pathogenic variants in genes encoding ion channels that result in pathological ion currents. Channelopathies include long-QT syndrome (LQTS), Brugada syndrome (BrS), catecholaminergic polymorphic ventricular tachycardia (CPVT), and short-QT syndrome (SQTS). In addition to the patient's clinical presentation, history and clinical tests, the main diagnostic tools are electrocardiography and genetic testing to identify known gene mutations. Early and correct diagnosis as well as further risk stratification of affected individuals and their relatives are paramount for prognosis. The recent availability of risk score calculators for LQTS and BrS allows SCD risk to be accurately estimated. The extent to which these improve patient selection for treatment with an implantable cardioverter-defibrillator (ICD) system is currently unknown. In most cases, initiation of basic therapy in asymptomatic patients in the form of avoidance of triggers, which are usually medication or stressful situations, is sufficient and contributes to risk reduction. In addition, there are other risk-reducing prophylactic measures, such as permanent medication with nonselective β‑ blockers (for LQTS and CPVT) or mexiletine for LQTS3. Patients and their family members should be referred to specialized outpatient clinics for individual risk stratification in the sense of primary prophylaxis.

DX single-lead implantable cardioverter-defibrillator system with a floating atrial dipole: when, to whom, and why?

The article reflects information for cardiologists, cardiac surgeons, doctors pro­gramming implanted antiarrhythmic devices, employees and residents of the depart­ments of cardiology and cardiac surgery. Most often, we choose a model of an implantable cardioverter-defibrillator (ICD) strictly individually for each patient, based on the anamnesis characteristics, safety and highest efficiency of ICD systems offered on the market. With each new ICD model, manufacturing companies strive to minimize the number of implantable components and develop better algorithms to discriminate between atrial tachyarrhythmias and true ventricular tachyarrhythmias. However, the risk of inappropriate ICD therapy still remains high. Thus, attending physicians and cardiologists programming implantable antiarrhythmic devices often face difficulties in correcting ICD settings and planning further treatment of a patient with shocks caused by atrial tachyarrhythmias. The authors sought to form an idea about the features of a single-chamber ICD recording atrial potentials using a floating dipole, as well as the advantages of the DX system over classical single-chamber ICD systems, and to define a type of a patient for whom this implantable system would be the best choice preventing sudden cardiac death.

Ability to remotely monitor atrial high-rate episodes using a single-chamber implantable cardioverter-defibrillator with a floating atrial sensing dipole.

To allow timely initiation of anticoagulation therapy for the prevention of stroke, the European guidelines on atrial fibrillation (AF) recommend remote monitoring (RM) of device-detected atrial high-rate episodes (AHREs) and progression of arrhythmia duration along pre-specified strata (6 min…<1 h, 1 h…<24 h, ≥ 24 h). We used the MATRIX registry data to assess the capability of a single-lead implantable cardioverter-defibrillator (ICD) with atrial sensing dipole (DX ICD system) to follow this recommendation in patients with standard indication for single-chamber ICD. In 1841 DX ICD patients with daily automatic RM transmissions, electrograms of first device-detected AHREs per patient in each duration stratum were adjudicated, and the corresponding positive predictive values (PPVs) for the detections to be true atrial arrhythmia were calculated. Moreover, the incidence and progression of new-onset AF was assessed in 1451 patients with no AF history. A total of 610 AHREs ≥6 min were adjudicated. The PPV was 95.1% (271 of 285) for episodes 6min…<1 h, 99.6% (253/254) for episodes 1 h…<24 h, 100% (71/71) for episodes ≥24 h, or 97.5% for all episodes (595/610). The incidence of new-onset AF was 8.2% (119/1451), and in 31.1% of them (37/119), new-onset AF progressed to a higher duration stratum. Nearly 80% of new-onset AF patients had high CHA2DS2-VASc stroke risk, and 70% were not on anticoagulation therapy. Age was the only significant predictor of new-onset AF. A 99.7% detection accuracy for AHRE ≥1 h in patients with DX ICD systems in combination with daily RM allows a reliable guideline-recommended screening for subclinical AF and monitoring of AF-duration progression.

Rationale and design of the Lead Evaluation for Defibrillation and Reliability study: Safety and efficacy of a novel ICD lead design.

Implantable cardioverter defibrillators (ICD) are indicated for primary and secondary prevention of sudden cardiac arrest. Despite enhancements in design and technologies, the ICD lead is the most vulnerable component of the ICD system and failure of ICD leads remains a significant clinical problem. A novel, small-diameter, lumenless, catheter-delivered, defibrillator lead was developed with the aim to improve long-term reliability. The Lead Evaluation for Defibrillation and Reliability (LEADR) study is a multi-center, single-arm, Bayesian, adaptive design, pre-market interventional pivotal clinical study. Up to 60 study sites from around the world will participate in the study. Patients indicated for a de novo ICD will undergo defibrillation testing at implantation and clinical assessments at baseline, implant, pre-hospital discharge, 3 months, 6 months, and every 6 months thereafter until official study closure. Patients may be participating for a minimum of 18 months to approximately 3 years. Fracture-free survival will be evaluated using a Bayesian statistical method that incorporates both virtual patient data (combination of bench testing to failure with in-vivo use condition data) with clinical patients. The clinical subject sample size will be determined using decision rules for number of subject enrollments and follow-up time based upon the observed number of fractures at certain time points in the study. The adaptive study design will therefore result in a minimum of 500 and a maximum of 900 patients enrolled. The LEADR Clinical Study was designed to efficiently provide evidence for short- and long-term safety and efficacy of a novel lead design using Bayesian methods including a novel virtual patient approach.

Single Lead Implantable Cardioverter Defibrillator (ICD) with a Floating Atrial Dipole: A Systematic Review and Non-Comparative Meta-Analysis

Background: A DX implantable cardioverter defibrillator (ICD) system consists of an ICD and a shock lead equipped with two ring electrodes positioned in the atrium, referred to as the DX-lead. This system allows the collection of atrial signals using a single lead. Multiple studies on the device have been conducted over more than a decade. Aims: The aim of this study is to summarise these data in a non-comparative meta-analysis. Methods: A systematic literature review targeting publications on studies including a certain type of ICD, VR-DX ICD, was conducted. Subsequently a meta-analysis of proportions was conducted. Endpoints selected for evaluation included p-wave amplitude (at day 0, &lt;6 months, 6-12 months and &gt;12 months), appropriate and inappropriate shock rates, and all-cause mortality. Results: One randomised controlled trial, 11 prospective cohort studies and registries, and two retrospective studies were selected for analysis. P-wave amplitudes were consistently in a range where they can support clinical decision making across studies and remained stable over a follow-up of up to two years. Pooled shock incidence was consistent with industry standard for appropriate (10.7%) and inappropriate shocks (2.4%) across studies. All-cause mortality was at an average of 5%, increasing, as expected, with duration of study follow-up. Like shock results, mortality was within the expected range. Conclusion: This analysis shows that the VR-DX ICD system works reliably and provides an added benefit compared to single chamber ICD in the form of atrial sensing. Atrial view without requiring a second lead provides clinicians with an attractive, hardware-sparing option for the continuous monitoring of atrial activity.

Experience of using the of subcutaneous cardioverter-defibrillators in the world practice: review

The article provides a review of international clinical studies on the use of a subcutaneous implantable cardioverter-defibrillator (ICD) in comparison with classical intravenous defibrillation systems. Subcutaneous ICDs have shown themselves to be a worthy alternative to intravenous defibrillating systems for the primary prevention of sudden cardiac death, when the patient is not indicated for anti-tachy stimulation and anti-brady stimulation. World experience on the use of subcutaneous ICDs proves the safety and effectiveness of the functioning of the subcutaneous ICD system, excluding from the patient’s life the formidable risks associated with the implantation procedure and further functioning of the classical intravenous ICD system.

Bradycardia in Patients with Subcutaneous Implantable Defibrillators-An Overestimated Problem? Experience from a Large Tertiary Centre and a Review of the Literature.

The subcutaneous ICD (S-ICD) has developed as a valuable alternative to transvenous implantable cardioverter defibrillator (ICD) systems. However there are certain peculiarities which are immanent to the S-ICD and may limit its use. Besides oversensing the main issue is the missing option for antibradycardia pacing. To evaluate the actual need for pacing during follow-up and changes to transvenous ICD we analyzed our large tertiary centre registry and compared it with data from other large cohorts and trials. We found out that in the 398 patients from our centre, there was a need for changing to a transvenous ICD in only 2 patients (0.5%) during a follow-up duration of almost 3 years. This rate was comparable to data obtained from other large data sets so that in the pooled analysis of almost 4000 patients the rate of bradycardia-associated complications was only 0.3%. The use of the S-ICD is safe in a variety of heart diseases and the need for antibradycardia stimulation is a very rare complication throughout many different large studies. Clinicians may take these results into account when opting for a certain ICD system and the S-ICD may be chosen more often also in elderly patients, in whom the risk for bradycardia is deemed higher.

Efficacy and Safety of an Extravascular Implantable Cardioverter–Defibrillator

BackgroundThe extravascular implantable cardioverter–defibrillator (ICD) has a single lead implanted substernally to enable pause-prevention pacing, antitachycardia pacing, and defibrillation energy similar to that of transvenous ICDs. The safety and efficacy of extravascular ICDs are not yet known.MethodsWe conducted a prospective, single-group, nonrandomized, premarket global clinical study involving patients with a class I or IIa indication for an ICD, all of whom received an extravascular ICD system. The primary efficacy end point was successful defibrillation at implantation. The efficacy objective would be met if the lower boundary of the one-sided 97.5% confidence interval for the percentage of patients with successful defibrillation was greater than 88%. The primary safety end point was freedom from major system- or procedure-related complications at 6 months. The safety objective would be met if the lower boundary of the one-sided 97.5% confidence interval for the percentage of patients free from such complications was greater than 79%.ResultsA total of 356 patients were enrolled, 316 of whom had an implantation attempt. Among the 302 patients in whom ventricular arrhythmia could be induced and who completed the defibrillation testing protocol, the percentage of patients with successful defibrillation was 98.7% (lower boundary of the one-sided 97.5% confidence interval [CI], 96.6%; P<0.001 for the comparison with the performance goal of 88%); 299 of 316 patients (94.6%) were discharged with a working ICD system. The Kaplan–Meier estimate of the percentage of patients free from major system- or procedure-related complications at 6 months was 92.6% (lower boundary of the one-sided 97.5% CI, 89.0%; P<0.001 for the comparison with the performance goal of 79%). No major intraprocedural complications were reported. At 6 months, 25 major complications were observed, in 23 of 316 patients (7.3%). The success rate of antitachycardia pacing, as assessed with generalized estimating equations, was 50.8% (95% CI, 23.3 to 77.8). A total of 29 patients received 118 inappropriate shocks for 81 arrhythmic episodes. Eight systems were explanted without extravascular ICD replacement over the 10.6-month mean follow-up period.ConclusionsIn this prospective global study, we found that extravascular ICDs were implanted safely and were able to detect and terminate induced ventricular arrhythmias at the time of implantation. (Funded by Medtronic; ClinicalTrials.gov number, NCT04060680.)

Real-Life Inter-Rater Variability of the PRAETORIAN Score Values.

(1) Background: The PRAETORIAN score is a tool developed for postoperative evaluation of the position of subcutaneous implantable cardioverter-defibrillator systems. The aim of our study was to evaluate the real-life inter-rater variability of the PRAETORIAN score, based on chest radiographs of S-ICD patients reviewed by independent clinical raters. (2) Methods: Postoperative chest X-rays of patients that underwent S-ICD implantation were evaluated by five clinical raters who gave values of the PRAETORIAN score. Ratings were then compared in a fully crossed manner to determine the inter-rater variability of the attributed scores. (3) Results: In total, 87 patients were included in the study. In the case of the most important final risk category of the PRAETORIAN score, the mean Light’s kappa was 0.804, the Fleiss’ kappa was 0.249, and the intraclass correlation was 0.38. The final risk category was identically determined by all five raters in 75.86% of patients, by four raters in 14.94%, and by three raters in 9.20% of patients. (4) Conclusions: The overall inter-rater variability of the PRAETORIAN score in a group of electrophysiologists experienced in S-ICD implantation, yet previously naive to the PRAETORIAN score, and self-trained in its utilization, was only modest in our study. Appropriate use of the score might require training of clinical raters.

Subcutaneous finger cardioverter-defibrillator in low weight paediatric patients: a case series.

Placement of traditional transvenous implantable cardioverter defibrillator (ICD) system in low-weight children is often difficult because of their vessel size, the elevated risk of lead malfunction and failure, children's growth and various anatomic constraints, creating the need for alternative solutions. Subcutaneous array leads combined with an abdominally placed ICD device can minimize the surgical approach. In this case series, we analyse the data behind indications for subcutaneous finger cardioverter defibrillator (SFCD) and discuss the preliminary clinical experience in low-weight children. We considered 4 consecutive children (mean age 3.9 years, range 3-5.5 years, mean body weight 17.6 Kg, range 14-23 Kg) who underwent SFCD implant from April 2016 to August 2020. All patients showed a good compliance to the device system with no complications (infections or skin erosions). No patients experienced in the observation period (mean time 44.5±21.5 months) sustained ventricular arrhythmias requiring shocks. No inappropriate shocks released by the device occurred. No significant changes were observed in LET (lowest energy tested) performed around 24 months of follow-up. All patients showed a good compliance and stable atrio-ventricular sensing and pacing thresholds. In smaller children in whom a transvenous approach is not feasible or not possible for anatomic reasons, the SFCD appears to be a safe method to prevent SCD with little surgical trauma and preservation of an intact vascular system, providing an adequate bridge to transvenous ICD or subcutaneous ICD implant late in the life.

Age-related differences and associated mid-term outcomes of subcutaneous implantable cardioverter-defibrillators: A propensity-matched analysis from a multicenter European registry.

A few limited case series have shown that the subcutaneous implantable cardioverter-defibrillator (S-ICD) system is safe for teenagers and young adults, but a large-scale analysis currently is lacking. The purpose of this study was to compare mid-term device-associated outcomes in a large real-world cohort of S-ICD patients,stratified by age at implantation. Two propensity-matched cohorts of teenagers + young adults (≤30 years old) and adults (>30 years old) were retrieved from the ELISIR Registry. The primary outcome was the comparison of inappropriate shock rate. Complications, freedom from sustained ventricular arrhythmias, and overall and cardiovascular mortality were deemed secondary outcomes. Teenagers + young adults represented 11.0% of the entire cohort. Two propensity-matched groups of 161 patients each were used for the analysis. Median follow-up was 23.1 (13.2-40.5) months. In total, 15.2% patients experienced inappropriate shocks, and 9.3% device-related complications were observed, with no age-related differences in inappropriate shocks (16.1% vs 14.3%; P = .642) and complication rates (9.9% vs 8.7%; P = .701). At univariate analysis, young age was not associated with increased rates of inappropriate shocks (hazard ratio [HR] 1.204 [0.675-2.148]: P = .529). At multivariate analysis, use of the SMART Pass algorithm was associated with a strong reduction in inappropriate shocks (adjusted HR 0.292 [0.161-0.525]; P <.001), whereas arrhythmogenic right ventricular cardiomyopathy (ARVC) was associated with higher rates of inappropriate shocks (adjusted HR 2.380 [1.205-4.697]; P = .012). In a large multicenter registry of propensity-matched patients, use of the S-ICD in teenagers/young adults was safe and effective. The rates of inappropriate shocks and complications between cohorts were not significantly different. The only predictor of increased inappropriate shocks was a diagnosis of ARVC.

The need for a subsequent transvenous system in patients implanted with subcutaneous implantable cardioverter-defibrillator

The absence of pacing capabilities may reduce the appeal of subcutaneous implantable cardioverter-defibrillator (S-ICD) devices for patients at risk for conduction disorders or with antitachycardia pacing (ATP)/cardiac resynchronization (CRT) requirements. Reports of rates of S-ICD to transvenous implantable cardioverter-defibrillator (TV-ICD) system switch in real-world scenarios are limited. The purpose of this study was to investigate the need for a subsequent transvenous (TV) device in patients implanted with an S-ICD and its predictors. All patients implanted with an S-ICD were enrolled from the multicenter, real-world iSUSI (International SUbcutaneouS Implantable cardioverter defibrillator) Registry. The need for a TV device and its clinical reason, and appropriate and inappropriate device therapies were assessed. Logistic regression with Firth penalization was used to assess the association between baseline and procedural characteristics and the overall need for a subsequent TV device. A total of 1509 patients were enrolled (age 50.8 ± 15.8 years; 76.9% male; 32.0% ischemic; left ventricular ejection fraction 38% [30%-60%]). Over 26.5 [13.4-42.9] months, 155 (10.3%) and 144 (9.3%) patients experienced appropriate and inappropriate device therapies, respectively. Forty-one patients (2.7%) required a TV device (13 bradycardia; 10 need for CRT; 10 inappropriate shocks). Body mass index (BMI) >30 kg/m2 and chronic kidney disease (CKD) were associated with need for a TV device (odds ratio [OR] 2.57 [1.37-4.81], P = .003; and OR 2.67 [1.29-5.54], P = .008, respectively). A low rate (2.7%) of conversion from S-ICD to a TV device was observed at follow-up, with need for antibradycardia pacing, ATP, or CRT being the main reasons. BMI >30 kg/m2 and CKD predicted all-cause need for a TV device.

Age-related differences and associated outcomes of S-ICD: insights from a large, european, multicenter, real-world registry

Abstract Funding Acknowledgements Type of funding sources: None. Background Young patients often represent the most suitable candidates for an entirely subcutaenous implantable cardioverter defibrillator (S-ICD) system, since they have to face a lifetime of device therapy and they rarely have a pre-existing or concurrent pacing or cardiac resynchronization therapy (CRT) indication. Moreover, S-ICD offers lower rate and a safer management of lead and major procedure-related complications. To date, a few limited case series and experiences with S-ICD in teenagers and young adults have shown that the S-ICD system is safe and feasible in this population, with a rate of inappropriate shocks (IS) comparable to transvenous (TV) ICD, but focused analysis on a large scale are currently lacking in this setting. Purpose The aim of the current study was to compare the age-related differences observed in patient selection, baseline characteristics, and device long-term associated outcomes in a large real world cohort of S-ICD recipients. The primary outcome of the study was defined as the comparisons of the IS rate observed during the entirety of follow up in the teenagers/young adult vs the adult populations. Rate of complications, freedom from sustained ventricular arrhythmic events, overall and cardiovascular mortality were also assessed in the two cohorts and assessed as secondary outcomes. Methods All S-ICD recipients in the ELISIR project were enrolled in the current study. Patients were classified into teenagers + young adults (≤ 30 years old) vs adults (&amp;gt; 30 years old), depending from patient age at device implantation (Figure 1). Rates of device-related complications and IS were compared between the cohorts. Results A total of 1349 patients were extracted from the ELISIR project. Teenagers and young adults represented 12.4% of the registry (n=56 teenagers; n=112 young adults). Patients were followed-up for a median of 23.1 [12.6–37.9] months. Overall, 117 (8.7%) patients experienced inappropriate S-ICD shocks and 100 (7.4%) device related complications were observed, with no age-related differences. IS resulted more frequent in the teenager and young adult cohort (14.3% vs 7.9%; p=0.006). Figure 2 reports Kaplan Meier curves for the occurrence of IS. At univariate analysis, young age was associated with IS, but after correcting for differences in arrhythmic substrate, this association resulted non-significant (aHR: 1.428 [0.883–2.331]; p=0.146). The use of SMART pass algorithm was instead associated to a strong reduction in IS (aHR 0.367 [0.245–0.548]; p&amp;lt;0.001). Conclusion The use of S-ICD in teenagers/young adults resulted safe and effective. Indeed, the rate of complications between teenagers/young adults and adults was not significantly different. Although a higher rate of IS was observed in the teenagers/young adults, when accounting for differences in baseline substrate and comorbidities, young age did not result associated with an increased risk of IS.