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Kaplan-Meier curve showing proportion of patients with event-free survival. K-M indicates Kaplan-Meier; post-Op, postoperative.
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Background
Up to 40% of patients with transvenous implantable cardioverter‐defibrillator (ICD) experience lead‐associated complications and may suffer from high complication rates when lead extraction is indicated. Subcutaneous ICD may represent a feasible alternative; however, the efficacy of the subcutaneous ICD in the detection and treatment of...
Context in source publication
Citations
... Therefore, a new device has been designed in which the lead is completely implanted subcutaneously without the need for vascular access 3 . The safety and effectiveness of this subcutaneous implantable cardioverter-defibrillator (S-ICD) in effectively treating episodes of ventricular fibrillation (VF) have been confirmed by multiples studies 2,4,5 . The introduction of this device in Mexico has opened up the door to new treatment opportunities for primary and secondary prevention of sudden death in patients with various sudden death related diseases such as channelopathies, cardiomyopathies, etc.). ...
... 13 However, few studies have been conducted on the performance of S-ICD in patients with cardiomyopathies and channelopathies. [20][21][22][23][24][25][26] Because of predisposing electrocardiogram (ECG) depolarization/repolarization changes, these patients have a potentially increased risk of double QRS counting or P-and/or T-wave oversensing (TWO), potentially inducing IS delivery. Long-term data on modern S-ICD and the type of implantation technique in patients with cardiomyopathies and channelopathies are lacking. ...
... 13,15,[17][18][19] However, data on the performance of the S-ICD in patients with cardiomyopathies and channelopathies are scant, excluding observations on specific patient groups. [20][21][22][23][24][25][26] Moreover, there are concerns regarding the presence of ECG depolarization/repolarization abnormalities, which may trigger IS, and the inability to deliver ATP, which may be an effective 'pain-free' therapy. In a previous study by Rudic et al., 22 which involved patients with various IADs (24 with BrS, 17 with IVF, 6 with LQTS, 1 with short-QT syndrome, 3 with catecholaminergic polymorphic VT, 8 with HCM, and 3 with ACM) who had received an S-ICD, the IS rate was 3.2% over a median follow-up of 31.0 ± 14.2 months. ...
... [20][21][22][23][24][25][26] Moreover, there are concerns regarding the presence of ECG depolarization/repolarization abnormalities, which may trigger IS, and the inability to deliver ATP, which may be an effective 'pain-free' therapy. In a previous study by Rudic et al., 22 which involved patients with various IADs (24 with BrS, 17 with IVF, 6 with LQTS, 1 with short-QT syndrome, 3 with catecholaminergic polymorphic VT, 8 with HCM, and 3 with ACM) who had received an S-ICD, the IS rate was 3.2% over a median follow-up of 31.0 ± 14.2 months. In the Effortless study cohort of S-ICD patients with channelopathies, the incidence of IS was 8.5% over 3.2 years of follow-up and the annualized IS rate was lower among S-ICD patients than TV-ICD patients (2.7%/year vs. 3.8%year). ...
Background:
Patients with cardiomyopathies and channelopathies are usually younger and have a predominantly arrhythmia-related prognosis; they have nearly normal life expectancy thanks to the protection against sudden cardiac death provided by the implantable cardioverter defibrillator (ICD). The subcutaneous ICD (S-ICD) is an effective alternative to the transvenous ICD, and has evolved over the years.
Objective:
To evaluate the rate of inappropriate shocks (IS), appropriate therapies and device-related complications in patients with cardiomyopathies and channelopathies who underwent modern S-ICD implantation.
Methods:
We enrolled consecutive patients with cardiomyopathies and channelopathies who had undergone implantation of a modern S-ICD from January 2016 to December 2020, and who were followed-up until December 2022.
Results:
A total of 1338 S-ICD implantations were performed within the observation period. Of these patients, 628 had cardiomyopathies or channelopathies. The rate of IS at 12 months was 4.6% (95%CI:2.8-6.9) in patients with cardiomyopathies and 1.1% (95%CI:0.1-3.8) in patients with channelopathies (P=0.032). No significant differences were noted over a median follow-up of 43 months (HR:0.76; 95%CI:0.45-1.31; P=0.351). The rate of appropriate shocks at 12 months was 2.3% (95%CI:1.1-4.1) in patients with cardiomyopathies and 2.1% (95%CI:0.6-5.3) in patients with channelopathies (P=1.0). The rate of device-related complications was 0.9% (95%CI:0.3-2.3) and 3.2% (95%CI:1.2-6.8), respectively (P=0.074). No significant differences were noted over the entire follow-up.The need for pacing was low, occurring in 0.7% of patients.
Conclusions:
Modern S-ICDs may be a valuable alternative to transvenous ICDs in patients with cardiomyopathies and channelopathies. Our findings suggest that modern S-ICD therapy carries a low rate of IS.
... Additionally, despite important concerns regarding inappropriate shock rates among patients with HCM and an S-ICD, published data has overall been reassuring. Single arm studies have reported IAS are uncommon in this population [51][52][53][54] and a recent comparative study demonstrated inappropriate therapy rates were more common with TV-ICD, due to inappropriate antitachycardia pacing with similar rates of IAS [55]. ...
... While limited studies have suggested good outcomes with the S-ICD in these patients [53,56], patients with Brugada syndrome require special consideration due to the Brugada pattern itself, as well as the dynamic nature of depolarization and repolarization often seen with this syndrome. ECG screening failure is overall more common in Brugada syndrome compared to other primary arrhythmia syndromes (18% versus 5%) [57]. ...
Purpose of Review
While the subcutaneous (S-) implantable cardioverter-defibrillator (ICDs) is an alternative to the transvenous (TV-) ICD in many patients, optimal use remains unclear. In this review, we summarize recent clinically relevant data on sensing algorithms, inappropriate shocks, defibrillation testing, and battery and electrode failures.
Recent Findings
Changes in sensing algorithms and S-ICD programming have significantly decreased inappropriate shock rates. Avoiding fat below the S-ICD coil and can is key for reducing the defibrillation threshold. While S-ICD battery and electrode failures have resulted in recalls, system components remain commercially available since failure rates are low and no other similar devices are available.
Summary
The S-ICD is a good alternative to the TV-ICD for many patients, and particularly in light of recently developed device algorithms and improvements in implant technique. Future research will need to better understand: the impact of S-ICD electrode and battery failures and the potential for integrating leadless pacing into a modular S-ICD platform.
... 200,201 Reassuringly though, preliminary reports of patients with BrS with subcutaneous ICD indicate that they are not necessarily at greater risk of inappropriate shocks. 202,203 In younger and smaller children, an Currently, however, ablation is mostly reserved for patients with recurrent ICD shocks that cannot be managed with medical therapy or for those in whom an ICD is indicated but not implanted (eg, strong patient preference). There are insufficient data to support its use in asymptomatic patients. ...
Brugada syndrome (BrS) is an “inherited” condition characterized by predisposition to syncope and cardiac arrest, predominantly during sleep. The prevalence is ∼1:2,000, and is more commonly diagnosed in young to middle-aged males, although patient sex does not appear to impact prognosis. Despite the perception of BrS being an inherited arrhythmia syndrome, most cases are not associated with a single causative gene variant. Electrocardiogram (ECG) findings support variable extent of depolarization and repolarization changes, with coved ST-segment elevation ≥2 mm and a negative T-wave in the right precordial leads. These ECG changes are often intermittent, and may be provoked by fever or sodium channel blocker challenge. Growing evidence from cardiac imaging, epicardial ablation, and pathology studies suggests the presence of an epicardial arrhythmic substrate within the right ventricular outflow tract. Risk stratification aims to identify those who are at increased risk of sudden cardiac death, with well-established factors being the presence of spontaneous ECG changes and a history of cardiac arrest or cardiogenic syncope. Current management involves conservative measures in asymptomatic patients, including fever management and drug avoidance. Symptomatic patients typically undergo implantable cardioverter defibrillator insertion, with quinidine and epicardial ablation used for patients with recurrent arrhythmia. This review summarizes our current understanding of BrS and provides clinicians with a practical approach to diagnosis and management.
... In fact, the morphology of the recorded signal is different from standard ICDs using intracardiac leads, but both systems can accurately detect the occurrence of ventricular tachyarrhythmias with a high degree of sensitivity. 15,16 Long-term ECG recording is made possible also by implantable loop recorders. 17 Unlike pacemakers and ICDs, implantable loop recorders are inserted under the skin without intracardiac leads and the electrical activity of the heart is recorded using subcutaneous electrodes. ...
... In fact, it has been reported that the accuracy of the s-ICD in arrhythmia detection is very high. 15,16 A young competitive cyclist of 26 years of age, affected by arrhythmogenic right ventricular cardiomyopathy, was referred for poorly tolerated episodes of sustained monomorphic ventricular tachycardia. The patient, informed of the advantages and disadvantages of transvenous and subcutaneous ICD, preferred s-ICD implantation. ...
The importance of physical activity is worldwide known, not only for healthy subjects but also for patients with heart disease. In particular, an accurate balance between risks and benefits of physical activity is necessary for patients with implantable defibrillator (ICD). The guidelines do not offer strict indications regarding the indications and limitations in sports for ICD patients, but it is of pivotal importance to guarantee their safety: an adequate preimplantation assessment also with device selection and tailored programming can avoid potential adverse events (like inappropriate shocks, lead fracture or dislocation, undersensing of ventricular arrhythmias). The use of improving technology, caution, common sense, and open discussion with single patients can help physicians to make the best decisions.
... Collectively, these studies indicate a relatively higher proportion of IAS in patients with BrS treated with an S-ICD, but these data represent populations before SP was available. Recently, Rudic et al. 23 reported low prevalence (3%) of IAS in a single-centre study including 62 S-ICD patients with inherited primary arrhythmia syndromes. ...
Aims:
Ajmaline challenge can unmask subcutaneous implantable cardioverter-defibrillator (S-ICD) screening failure in patients with Brugada syndrome (BrS) and non-diagnostic baseline electrocardiogram (ECG). The efficacy of the SMART Pass (SP) filter, a high-pass filter designed to reduce cardiac oversensing (while maintaining an appropriate sensing margin), has not yet been assessed in patients with BrS. The aim of this prospective multicentre study was to investigate the effect of the SP filter on dynamic Brugada ECG changes evoked by ajmaline and to assess its value in reducing S-ICD screening failure in patients with drug-induced Brugada ECGs.
Methods and results:
The S-ICD screening with conventional automated screening tool (AST) was performed during ajmaline challenge in subjects with suspected BrS. The S-ICD recordings were obtained before, during and after ajmaline administration and evaluated by the means of a simulation model that emulates the AST behaviour with and without SP filter. A patient was considered suitable for S-ICD if at least one sensing vector was acceptable in all tested postures. A sensing vector was considered acceptable in the presence of QRS amplitude >0.5 mV, QRS/T-wave ratio >3.5, and sense vector score >100. Of the 126 subjects (mean age: 42 ± 14 years, males: 61%, sensing vectors: 6786), 46 (36%) presented with an ajmaline-induced Brugada type 1 ECG. Up to 30% of subjects and 40% of vectors failed the screening during the appearance of Brugada type 1 ECG evoked by ajmaline. The S-ICD screening failure rate was not significantly reduced in patients with Brugada ECGs when SP filter was enabled (30% vs. 24%). Similarly, there was only a trend in reduction of vector-failure rate attributable to the SP filter (from 40% to 36%). The most frequent reason for screening failure was low QRS amplitude or low QRS/T-wave ratio. None of these patients was implanted with an S-ICD.
Conclusion:
Patients who pass the sensing screening during ajmaline can be considered good candidates for S-ICD implantation, while those who fail might be susceptible to sensing issues. Although there was a trend towards reduction of vector sensing failure rate when SP filter was enabled, the reduction in S-ICD screening failure in patients with Brugada ECGs did not reach statistical significance.
Clinical trial registration:
https://clinicaltrials.gov Unique Identifier NCT04504591.
... The main findings of the study are as follows: (1) Patients with IS had a spontaneous type 1 BrS ECG pattern more frequently at diagnosis and/or during follow-up. The ECG pattern in BrS is often dynamic, either spontaneously or secondary to drugs, fever, and increased vagal tone, [12][13][14][15][16][17] and it is characterized by marked repolarization abnormalities, often leading not only to temporary S-ICD screening unsuitability but also to inadequate sensing and IS, as previously stated by Rudic et al., 18 ...
... Abbreviation: BrS, Brugada syndrome; CI, confidence interval; ECG, electrocardiogram; HR, hazard ratio; IS, inappropriate shock; S-ICD, subcutaneous implantable cardioverter-defibrillator.Our findings suggest the potential benefit of an adequate screening process to select suitable candidates for S-ICD among BrS patients, especially in those diagnosed at a younger age. Besides the classical requirements, the new proposed criteria may include screening patients during or immediately after an exercise test7,17,18 and drug challenge,19 as well as using higher QRS voltage and DASS values and requiring more than one vector passed. The application of these new, stricter criteria plus other strategies, such us pharmacological treatment to reduce heart rate during exercise or advising the patient to avoid certain activities may result in a reduction of this frequent complication, minimizing the need for more aggressive solutions (e.g., repositioning of the electrode and/or the device, replacing the device with a TV-ICD), or choosing a transvenous device in the first place. ...
Background
Subcutaneous implantable cardioverter defibrillators (S‐ICDs) avoid complications secondary to transvenous leads, but inappropriate shocks (ISs) are frequent. Furthermore, IS data from patients with Brugada syndrome (BrS) with an S‐ICD are scarce.
Objective
We aimed to establish the frequency and predictors of IS in this population.
Methods
We analyzed the clinical and electrocardiographic characteristics, automated screening test data, device programming, and IS occurrence in adult patients with BrS with an S‐ICD.
Results
Thirty‐nine patients were enrolled (69% male, mean age at diagnosis 46±13 years, mean age at implantation 48±13 years). During a mean follow‐up of 26±21 months, 18% patients experienced IS. Patients with IS were younger at the time of diagnosis (36±8 versus 48±13 years, p=0.018) and S‐ICD implantation (38±9 versus 50±23 years, p=0.019) and presented with spontaneous type 1 Brugada ECG pattern more frequently at diagnosis or during follow‐up (71% versus 25%, p=0.018). During automated screening tests, patients with IS showed lower QRS voltage in the primary vector in the supine position (0.58±0.26 versus 1.10±0.35 mV, p=0.011) and lower defibrillator automated screening score (DASS) in the primary vector in the supine (123±165 versus 554±390 mV, p=0.005) and standing (162±179 versus 486±388 mV, p=0.038) positions. Age at diagnosis was the only independent predictor of IS (hazard ratio=0.873, 95% confidence interval: 0.767‐0.992, p=0.037).
Conclusion
IS was a frequent complication in patients with BrS with an S‐ICD. Younger age was independently associated with IS. A more thorough screening process might help prevent IS in this population.
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... A total of 84 patients received 167 extracardiac IAS. The random effect meta-analysis of the select studies (9,10,13,14,18,25,27,33,35,42,43,47) demonstrated that in the overall study population the IAS percentage of total shocks delivered due to extracardiac oversensing represent 22% (95% CI 8% -50%); the percentage was 6% (95% CI 3% -12%) in patients without the SP filter and 46% (95% CI 12% -84%) in patients with the SP filter ( Figure 3). The funnel plot appears symmetrical (Figure 4), without evidence of bias using both the Egger weighted regression method (P= 0.763) and the Begg rank test (P= 0.304). ...
... Educate patients to avoid the device causing the EMI or additional device reprogramming or repositioning is needed to overcome these problems. Although, in different studies and case-reports, we noted that the problem of oversensing related to MP was solved by setting a new configuration in device sensitivity (9,10,15,20,27,28,37,42,43). This is usually managed non-invasively via a change in sensing vector. ...
... This is usually managed non-invasively via a change in sensing vector. In the study of Rudic et al. [27] 2 of 62 patients (3.2%) experienced IAS. In 1 patient oversensing of pectoral MP, caused by suboptimal position of the lead, was resolved by placing it toward the right side of the sternum. ...
The subcutaneous implantable cardioverter defibrillator (S-ICD) is an established treatment for the prevention of sudden cardiac death. In the S-ICD studies, inappropriate shocks (IAS) rate were reported to renge between 5% to 25% and to be mainly due to cardiac and noncardiac oversensing.
... CPVT is characterized by a risk of VF without the need for bradycardia pacing; therefore, when it was possible, S-ICD was implanted in our patient following the removal of the endocardial leads. S-ICD is considered an important option in channelopathies [24,25]. ...
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is one of causes of sudden cardiac death in the young, especially in athletes. Diagnosis of CPVT may be difficult since all cardiological examinations performed at rest are usually normal, and exercise stress test-induced ventricular tachycardia is not commonly present. The identification of a pathogenic mutation in RYR2 or CASQ2 is diagnostic in CPVT. We report on a 20-year-old athlete who survived two sudden cardiac arrests during swimming. Moreover, he suffered repeated syncopal spells on exercise. The diagnosis was made only following genetic testing using a multi-gene panel, and the p.Arg420Gln RYR2 variant was identified. We present diagnostic and therapeutic issues in this young athlete with CPVT.
... Very little information is currently available on the use of S-ICDs in patients with long QT syndrome. Because of the changes observed in the T wave in these patients, one can expect a potentially higher rate of inappropriate shocks, but a recent study demonstrated that the prevalence of inappropriate shocks appears to be low [35]. ...
The introduction of a new technology always raises questions about its place compared with the reference technology. The use of an implantable cardioverter defibrillator to prevent sudden cardiac death is now a widely proven technique, with a clear statement of its indication in the guidelines. More recently, a subcutaneous implantable cardioverter defibrillator has been introduced, and appears to be an attractive technique as it removes the need to implant a lead inside the right ventricle to treat the patient, which should dramatically decrease the risk of complications over time. Currently, only one model of subcutaneous implantable cardioverter defibrillator is available on the market; its indications are the same as for transvenous implantable cardioverter defibrillators, except for patients who need stimulation because of conduction disorders or ventricular tachycardias that can potentially be treated effectively by antitachycardia pacing. The different technical characteristics of transvenous versus subcutaneous implantable cardioverter defibrillators therefore raise the question of which to choose in different clinical settings. The experts who participated in the preparation of this manuscript had three meetings, organized by the company Boston Scientific. Each expert prepared the draft of a section corresponding to a clinical situation. The choice between transvenous versus subcutaneous implantable cardioverter defibrillator was then voted on by all the experts. The results of the votes are presented in this manuscript, as it seemed important to us to show the disparities of opinion that can exist in certain situations. The votes were cast independently and anonymously.
