Search

To assess the risk of unsuccessful conversion of ventricular fibrillation during defibrillation testing (DFT) with the subcutaneous implantable cardioverter-defibrillator (S-ICD), the PRAETORIAN score has been proposed. The purpose of this study was to validate the PRAETORIAN score in a large S-ICD collective. A retrospective single-center analysis of S-ICD patients receiving intraoperative DFT was performed. DFT was performed using a stepwise protocol with 65-J standard polarity, change of polarity, increase to 80 J, and repositioning if necessary. If all DFTs failed, we switched to a transvenous ICD. Overall, 398 patients were analyzed (268 male [67.3%]; mean age 42.4 ± 15.9 years; mean body mass index [BMI] 25.9 ± 4.8 kg/m2). Successful DFT with the first ICD shock was observed in 264 patients (66.3%). One hundred fourteen patients were defibrillated with the second (n = 104) or third (n = 10) DFT after changing shock polarity and/or shock energy. Overall, 20 patients needed at least 3 DFT (ie, 80 J and/or re-positioning). The majority (n = 88 [65.7%]) of DFT failures occurred before 2015 with the first-generation S-ICD. PRAETORIAN score was an independent predictor of DFT failure (odds ratio [OR] 1.007; 95% confidence interval [CI] 1.003–1.011 P ≤.001), while whereas BMI alone was not (P =.31). Presence of hypertrophic cardiomyopathy (HCM) (OR 2.6; 95% CI 1.3–4.4; P =.004) was predictive for at least 1 unsuccessful DFT in our multivariate regression analysis. PRAETORIAN score proved to be a useful and valid predictive tool for successful DFT, whereas BMI only had a limited role. Patients with HCM were at increased risk for DFT failure or needed higher DFT energy. [ABSTRACT FROM AUTHOR]

Outcome comparisons among subcutaneous implantable cardioverter-defibrillator (S-ICD) recipients with nonischemic cardiomyopathies are scarce. The aim of this study was to evaluate differences in device-related outcomes among S-ICD recipients with different structural substrates. Patients enrolled in the i-SUSI (International SUbcutaneouS Implantable cardioverter defibrillator registry) project were grouped according to the underlying substrate (ischemic vs nonischemic) and subgrouped into dilated cardiomyopathy, hypertrophic cardiomyopathy, Brugada syndrome (BrS), arrhythmogenic right ventricular cardiomyopathy (ARVC). The main outcome of our study was to compare the rates of appropriate and inappropriate shocks and device-related complications. Among 1698 patients, the most common underlying substrate was ischemic (31.7%), followed by dilated cardiomyopathy (20.5%), BrS (10.8%), hypertrophic cardiomyopathy (8.5%), and ARVC (4.4%). S-ICD for primary prevention was more common in the nonischemic cohort (70.9% vs 65.4%; P =.037). Over a median (interquartile range) follow-up of 26.5 (12.6–42.8) months, no differences were observed in appropriate shocks between ischemic and nonischemic patients (4.8%/y vs 3.9%/y; log-rank, P =.282). ARVC (9.0%/y; hazard ratio [HR] 2.492; P =.001) and BrS (1.8%/y; HR 0.396; P =.008) constituted the groups with the highest and lowest rates of appropriate shocks, respectively. Device-related complications did not differ between groups (ischemic: 6.4%/y vs nonischemic: 6.1%/y; log-rank, P =.666), nor among underlying substrates (log-rank, P =.089). Nonischemic patients experienced higher rates of inappropriate shocks than did ischemic S-ICD recipients (4.4%/y vs 3.0%/y; log-rank, P =.043), with patients with ARVC (9.9%/y; P =.001) having the highest risk, even after controlling for confounders (adjusted HR 2.243; confidence interval 1.338–4.267; P =.002). Most S-ICD recipients were primary prevention nonischemic cardiomyopathy patients. Among those, patients with ARVC tend to receive the most frequent appropriate and inappropriate shocks and patients with BrS the least frequent appropriate shocks. [ABSTRACT FROM AUTHOR]

Hypertrophic cardiomyopathy (HCM) carries an increased risk of sudden cardiac death. Ventricular fibrillation (VF) is thought to be the common culprit arrhythmia. The purpose of this study was to describe the incidence and predictors of sustained ventricular arrhythmias (VTAs) in HCM patients. We retrospectively analyzed all patients with HCM and an implantable cardioverter-defibrillator (ICD) from a prospectively derived registry in 2 tertiary medical centers. Clinical, electrocardiographic, echocardiographic, ICD interrogation, and genetic data were collected and compared, first between patients with and without VTAs and then between patients with only VF and those with ventricular tachycardia (VT) with or without VF. Of the 1328 HCM patients, 207 (145 [70%] male; mean age 33 ± 16 years) were implanted with ICDs. Over a mean follow-up of 10 ± 6 years, 37 patients with ICDs (18%) developed sustained VTAs. These were associated with a family history of sudden cardiac death and a personal history of VTAs (P =.036 and P =.001, respectively). Sustained monomorphic VT was the most common arrhythmia (n = 26, 70%) and was linked to decreased left ventricular (LV) ejection fraction and increased LV end-systolic and end-diastolic diameters. Antitachycardia pacing (ATP) successfully terminated 258 (79%) of the 326 VT events. Mortality rates were comparable between patients with and without VTAs (4 [11%] vs 29 [17%]; P =.42) and between those with and without ICDs (24 [16%] vs 85 [20%]; P =.367). VT rather than VF is the most common arrhythmia in patients with HCM; it is amenable to ATP and is associated with lower LV ejection fraction and higher LV diameters. Therefore, ATP-capable devices may be considered in HCM patients with these LV features. [ABSTRACT FROM AUTHOR]

Currently the cornerstone of therapy for ventricular arrhythmic complications and sudden cardiac death prevention in Brugada syndrome (BrS) is an implantable cardioverter-defibrillator (ICD). BrS patient population differs from the majority of patients with an ICD implanted for structural heart disease, and as widely known, transvenous ICD (TV-ICD) systems have been associated with high complication rates in patients with BrS. Technological evolution of these devices has certainly reduced complications due to the device itself, but a careful preimplant screening of these patients is still essential. To date, criteria for an adequate screening process to select suitable candidates for a subcutaneous implantable cardioverter-defibrillator (S-ICD) from patients with BrS are sometimes nonstandardized and often lack important precautions that are instead fundamental to select the most suitable type of ICD for these patients. To better select suitable candidates for an S-ICD from patients with BrS, a full screening process should include screening during or immediately after an exercise test and after a drug provocation challenge test. We report an analysis of the "lights and shadows" of S-ICD for a correct use of this device in patients with BrS. [ABSTRACT FROM AUTHOR]

Background: No data regarding subcutaneous-implantable cardioverter defibrillator (S-ICD) technology in patients actively engaging in sports activities are available., Objective: This study aims to compare S-ICD performance between athletes and nonathletes., Methods: The primary outcome of the study was the comparison of overall device-related complications between athletes and nonathletes. Appropriate shocks, inappropriate shocks, and individual device-related complications were secondary outcomes., Results: A total of 1493 patients were extracted from the International Subcutaneous Implantable Cardioverter Defibrillator Registry (iSUSI) registry, of whom 152 (10.2%) were athletes, mostly engaging in dynamic sports (54.2%). Brugada syndrome, myocarditis, and arrhythmogenic right ventricular cardiomyopathy (ARVC) were more common in athletes (11.2% vs 3.3%, P < .001; 19.1% vs 9.0%, P < .001; 8.6% vs 2.8%, P < .001, respectively). During a median follow-up time of 25.5 (12.0-41.2) months, athletes were more likely to experience appropriate shocks (yearly rate: 7.2 [4.9-10.7] % vs 4.3 [3.6-5.1] %, P = .028), occurring more frequently during exercise (3.9% vs 0.6%, P < .001). This finding lost significance when adjusting for confounders (adjusted hazard ratio [aHR] 1.440 [0.909-2.281], P = .120). No differences were found in overall device-related complications (yearly rate: 3.3% vs 3.4%, P = .448) and inappropriate shocks (yearly rate: 5.3% vs 3.7%, P = 0.111). Myopotential oversensing (4.0% vs 1.3%, P = .011) was more common in athletes, as were lead infections (3.3% vs 0.9%, P =.008), with the latter clustering in the early postimplantation period., Conclusion: The S-ICD is a valid therapeutic option for preventing sudden cardiac death in athletes. Sports practice was not associated with an increased risk of complications or inappropriate shocks, although athletes are exposed to a higher risk of S-ICD infections in the early postoperative period., Competing Interests: Disclosures Dr Breitenstein has received consultant/speaker fees from Boston Scientific. Dr Martinek has received speaker`s honoraria from Boston Scientific. Dr Kaiser has received proctor fees from Boston Scientific. Dr Tilz consults for and has received speaker`s honoraria from Boston Scientific. Dr Tondo is a member of Boston Scientific advisory board. The other authors have no conflicts of interest to disclose., (Copyright © 2024 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Current evidence describing the characteristics of subcutaneous implantable cardioverter-defibrillator (S-ICD) therapy, its trend, and perioperative outcomes compared with transvenous implantable cardioverter-defibrillator (TV-ICD) based on a real-world, large-scale database is scarce.Objective: The purpose of this study was to identify the characteristics of current S-ICD therapy using a nationwide database.Methods: A retrospective analysis of ICD implantation was performed using a nationwide database obtained between 2016 and 2020. A total of 8690 patients implanted with ICD (median age 65 [52-72] year; 6902 men; 2021 S-ICD recipients) were analyzed.Results: Younger patients were more prone to have S-ICD (P <.001). A history of ventricular fibrillation (VF) (odds ratio [OR] 2.45; 95% confidence interval [CI] 2.04-2.93), nonsustained ventricular tachycardia (VT) (OR 1.73; 95% CI 1.36-2.21), Brugada syndrome (BrS) (OR 3.14; 95% CI 2.48-4.00), and dialysis treatment (OR 2.02; 95% CI 1.44-2.82) were independent predictors of S-ICD selection on mixed-model logistic analysis. The proportion of S-ICD implantations has been increasing (P <.001), especially in patients with BrS (P <.001) and dialysis (P = .04). The proportion of combined complications after S-ICD implantation was low (1.3%) in the unmatched cohort and was comparable to TV-ICD in the 1:1 propensity-matched cohort of 3354 patients (1.5% vs 2.3%; OR 0.65; 95% CI 0.38-1.10).Conclusion: S-ICD was more likely to be implanted in younger patients and those with a history of VF, nonsustained VT, BrS, and dialysis treatment. The proportion of S-ICD implantation increased, especially in patients with BrS. The incidence of in-hospital complications was low in S-ICD recipients. [ABSTRACT FROM AUTHOR]

Background: Recently, the Food and Drug Administration issued a recall for the subcutaneous implantable cardioverter-defibrillator (S-ICD) because of the possibility of lead ruptures and accelerated battery depletion.Objective: The aim of this study was to evaluate device-related complications over time in a large real-world multicenter S-ICD cohort.Methods: Patients implanted with an S-ICD from January 2015 to June 2020 were enrolled from a 19-institution European registry (Experience from the Long-term Italian S-ICD registry [ELISIR]; ClinicalTrials.gov identifier NCT0473876). Device-related complication rates over follow-up were collected. Last follow-up of patients was performed after the Boston Scientific recall issue.Results: A total of 1254 patients (median age 52.0 [interquartile range 41.0-62.2] years; 973 (77.6%) men; 387 (30.9%) ischemic) was enrolled. Over a follow-up of 23.2 (12.8-37.8) months, complications were observed in 117 patients (9.3%) for a total of 127 device-related complications (23.6% managed conservatively and 76.4% required reintervention). Twenty-seven patients (2.2%) had unanticipated generator replacement after 3.6 (3.3-3.9) years, while 4 (0.3%) had lead rupture. Body mass index (hazard ratio [HR] 1.063 [95% confidence interval 1.028-1.100]; P < .001), chronic kidney disease (HR 1.960 [1.191-3.225]; P = .008), and oral anticoagulation (HR 1.437 [1.010-2.045]; P = .043) were associated with an increase in overall complications, whereas older age (HR 0.980 [0.967-0.994]; P = .007) and procedure performed in high-volume centers (HR 0.463 [0.300-0.715]; P = .001) were protective factors.Conclusion: The overall complication rate over 23.2 months of follow-up in a multicenter S-ICD cohort was 9.3%. Early unanticipated device battery depletions occurred in 2.2% of patients, while lead fracture was observed in 0.3%, which is in line with the expected rates reported by Boston Scientific. [ABSTRACT FROM AUTHOR]

Competing Interests: Disclosure The authors have no conflicts of interest to disclose.

Background: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmia syndrome characterized by adrenergically induced ventricular arrhythmias in patients with structurally normal hearts. Initiating triggered arrhythmias, such as bidirectional ventricular tachycardia, often degenerate into reentrant arrhythmias, such as ventricular fibrillation (VF)., Objective: To determine whether the effectiveness of implantable cardioverter-defibrillator (ICD) shocks is dependent on rhythm type., Methods: It is a retrospective study of patients with CPVT who had undergone ICD implantation. Thirteen patients received ICDs (median age 15 years; range 9-43 years): 7 of 13 (54%) for cardiac arrest and 6 of 13 (46%) for syncope despite drug therapy. The median follow-up duration was 4.0 years (range 1.7-19.9 years). Nineteen reinterventions occurred, excluding generator replacements. Ten patients received 96 shocks (median 4 shocks; range 1-30 shocks). Eighty-seven shock electrograms were reviewed. Sixty-three (72%) shocks were appropriate, and 24 (28%) were inappropriate (T-wave oversensing 7 [29%], supraventricular arrhythmia 16 [67%], after self-terminating VF 1 [4%])., Results: Among appropriate shocks, 20 (32%) were effective in terminating sustained arrhythmia and 43 (68%) were ineffective. Shocks delivered to triggered arrhythmias nearly always failed (1 of 40 [3%] effective), while shocks delivered to VF were usually successful (19 of 23 [83%] effective; P < .001). Four patients received 17 appropriate antitachycardia pacing therapies for ventricular tachycardia: only 2 (12%) were effective. No patient died., Conclusions: The effectiveness of ICD shock therapy in CPVT depends on the mechanism of the rhythm treated. Shocks delivered to initiating triggered arrhythmias nearly always fail, whereas those for subsequent VF are usually effective. ICD programming in these patients is exceptionally challenging., (© 2013 Published by Heart Rhythm Society on behalf of Heart Rhythm Society.)

Background: Three incisions in the chest are necessary for implantation of the entirely subcutaneous implantable cardioverter-defibrillator (S-ICD). The superior parasternal incision is a possible risk for infection and a potential source of discomfort. A less invasive alternative technique of implanting the S-ICD electrode--the two-incision technique--avoids the superior parasternal incision., Objective: The purpose of this prospective cohort study was to evaluate the safety and efficacy of the two-incision technique for implantation of the S-ICD., Methods: Consecutive patients who received an S-ICD between October 2010 and December 2011 were implanted using the two-incision technique, which positions the parasternal part of the S-ICD electrode using a standard 11Fr peel-away sheath. All patients were routinely evaluated for at least 1 year for complications and device interrogation at the outpatient clinic., Results: Thirty-nine patients (46% male, mean age 44 ± 15 years) were implanted with a S-ICD using the two-incision technique. During mean follow-up of 18 months (range 14-27 months) no dislocations were observed, and there was no need for repositioning of either the ICD or the electrode. No serious infections occurred during follow-up except for 2 superficial wound infections of the pocket incision site. Device function was normal in all patients, and no inappropriate sensing occurred related to the implantation technique., Conclusion: The two-incision technique is a safe and efficacious alternative for S-ICD implantations and may help to reduce complications. The two-incision technique offers physicians a less invasive and simplified implantation procedure of the S-ICD., (Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)