Direct comparison of the novel automated screening tool (AST) versus the manual screening tool (MST) in patients with already implanted subcutaneous ICD

Personalized screening before subcutaneous cardioverter-defibrillator implantation: Usefulness and outcomes in clinical practice-the S-ICD screening SIS prospective study

BACKGROUND

Electrocardiographic screening before subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation is unsuccessful in around 10% of cases. A personalized screening method, by slightly moving the electrodes, to obtain a better R/T ratio has been described to overcome traditional screening failure.

OBJECTIVE

The objectives of the SIS study were to assess to what extent a personalized screening method improves eligibility for S-ICD implantation and to evaluate the inappropriate shock rate after such screening success.

METHODS

All consecutive patients eligible for an S-ICD implantation were prospectively recruited across 20 French centers between December 2019 and January 2022. In case of traditional screening failure, patients received a second personalized screening. If at least 1 vector was positive, the personalized screening was considered successful, and the patient was eligible for implantation.

RESULTS

The study included 474 patients (mean age, 50.4 ± 14.1 years; 77.4% men). Traditional screening was successful in 456 (96.2%) cases. This figure rose to 98.3% (n = 466; P = .002) when personalized screening was performed. All patients implanted after successful personalized screening had correct signal detection on initial device interrogation. Nevertheless, after 1-year follow-up, 3 of the 7 patients (43%) implanted with personalized screening experienced inappropriate shock vs 18 of the 427 patients (4.2%) with traditional screening and S-ICD implantation (P = .003).

CONCLUSION

Traditional S-ICD screening was successful in our study in a high proportion of patients. Considering the small improvement in success of screening and a higher rate of inappropriate shock, a strategy of personalized screening cannot be routinely recommended.

CLINICALTRIALS

gov identifier: NCT04101253.

Safety and Performance of the Subcutaneous Implantable Cardioverter Defibrillator Detection Algorithm INSIGHTTM in Pacemaker Patients

BACKGROUND

The use of the S-ICD is limited by its inability to provide backup pacing. Combined use of the S-ICD with a pacemaker may be a good choice in certain situations, yet current experience concerning the compatibility is limited. The goal of this study was to determine the safety and efficacy of the S-ICD in patients with a pacemaker.

METHODS

A total of 74 consecutive patients with a bipolar pacemaker were prospectively enrolled. First, surface rhythm strips were recorded in all possible pacemaker stimulation modes, to screen for T-wave oversensing (TWOS). Second, a S-ICD functional dummy was placed epicutaneously on the patient in the typical implant position. The same standardized pacing protocol was used as mentioned above, and every stimulation mode was recorded via S-ECG in all vectors.

RESULTS

In 16 patients (21.6%), programmed stimulation would have led to VT/VF detection. Triggered episodes were due to counting of the pacing spike(s), QRS complex, premature ventricular contractions, and/or additional TWOS. Three cases triggered in the bipolar stimulation mode. Oversensing was associated with lung emphysema and a reduced QRS amplitude in the S-ECG.

CONCLUSION

The combination of an S-ICD and a pacemaker may lead to inadequate shock delivery due to oversensing, even under programmed bipolar stimulation. Oversensing cannot be sufficiently predicted by the screening tool in pacemaker patients. Testing with an epicutaneous S-ICD dummy in all vectors and stimulation settings is recommended in patients with pre-existing pacemakers.

Comparison of Preoperative ECG Screening and Device-Based Vector Analysis in Patients Receiving a Subcutaneous Implantable Cardioverter-Defibrillator

Background and Objectives: Subcutaneous implantable cardioverter-defibrillators (S-ICDs) provide protection against sudden cardiac death from outside the cardiovascular system. ECG screening is a prerequisite for implantation, but the reproducibility of its results post-operatively in the device is only partial. We aimed to compare the results of ECG screening with device-based sensing vector analysis. Materials and Methods: We screened the hospital records of all S-ICD recipients in our clinic. All of them had pre-operative ECG screening performed (primary, secondary, and alternate vectors). The results were compared with device-based vector analysis to determine the relation of the pre- and post-operative vector availability. Results: Complete ECG screening and device-based vector analysis were obtained for 103 patients. At least two acceptable vectors were found in 97.1% of the patients pre-operatively and in 96.1% post-operatively. When comparing vectors in terms of agreement (OK or FAIL) pre- and post-operatively, in 89.3% of the patients, the result for the primary vector was the same in both situations; for the secondary, it was in 84.5%, and for the alternate, it was in 74.8% of patients, respectively. In 55.3% of patients, all three vectors were labeled the same (OK or FAIL); in 37.9%, two vectors had the same result, and in 6.8%, only one vector had the same result pre- and post-operatively. The number of available vectors was the same pre- and post-operatively in 62.1% of patients, while in 15.5%, it was lower, and in 22.3% of patients, it was higher than observed during screening. Conclusions: Routine clinical pre-operative screening allowed for a good selection of candidates for S-ICD implantation. All patients had at least one vector available post-operatively. The final number of vectors available in the device-based analysis in most patients was at least the same (or higher) than during screening. The repeatability of the positive result for a single vector was high.

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

BACKGROUND

Subcutaneous implantable cardioverter-defibrillators (S-ICDs) have been shown to be non-inferior to transvenous ICDs in the prevention of sudden cardiac death (SCD), but there is still a lack of evidence from clinical trials in China. We investigated whether S‑ICD implantation in the Chinese population is safe and feasible and should be promoted in the future.

METHODS

Consecutive patients undergoing S‑ICD implantation at our center were enrolled in this retrospective study. Data were collected within the median follow-up period of 554 days. Data concerning patient selection, implantation procedures, complications, and episodes of shock were analyzed.

RESULTS

In total, 70.2% of all 47 patients (median age = 39 years) were included for secondary prevention of SCD with different etiologies. Vector screening showed that 98% of patients were with > 1 appropriate vector in all postures. An intraoperative defibrillation test was not performed on six patients because of the high risk of disease deterioration, while all episodes of ventricular fibrillation induced post implantation were terminated by one shock. As expected, no severe complications (e.g., infection and device-related complications) were observed, except for one case of delayed healing of the incision. Overall, 15 patients (31.9%) experienced appropriate shocks (AS) with all episodes terminated by one shock. Two patients (4.3%) experienced inappropriate shocks (IAS) due to noise oversensing, resulting in a high Kaplan-Meier IAS-free rate of 95.7%.

CONCLUSION

Based on appropriate patient selection and standardized implantation procedures, this real-world study confirmed the safety and efficacy of S‑ICD in Chinese patients, indicating that it may help to promote the prevention of SCD in China.

Implantable cardioverter-defibrillators for hypertrophic cardiomyopathy: The Times They Are a-Changin'

The implantable cardioverter-defibrillator (ICD) is a life-saving therapy in patients with hypertrophic cardiomyopathy (HCM) at high risk of sudden cardiac death. The heterogeneity of clinical scenarios in HCM and the availability of ICDs with distinct characteristics emphasizes the need for selecting the right device for the right patient. There is growing awareness that unnecessarily complex devices can lead to short- and long-term complications without adding significant clinical benefits. Young patients have the greatest potential years of life gained from the ICD but are also most exposed to device-related complications. This increases the complexity of decision-making of ICD prescription in these often otherwise well patients in whom device selection should be tailored to preserve survival benefit without introducing morbidity. In the light of the multiple clinical phenotypes characterizing HCM, the present article offers evidence-based perspectives helpful in predicting the individual impact of the ICD and choosing the most appropriate device.

The Subcutaneous ICD: A Review of the UNTOUCHED and PRAETORIAN Trials

The ICD is an important part of the treatment and prevention of sudden cardiac death in many high-risk populations. Traditional transvenous ICDs (TV-ICDs) are associated with certain short- and long- term risks. The subcutaneous ICD (S-ICD) was developed in order to avoid these risks and complications. However, this system is associated with its own set of limitations and complications. First, patient selection is important, as S-ICDs do not provide pacing therapy currently. Second, pre-procedural screening is important to minimise T wave and myopotential oversensing. Finally, until recently, the S-ICD was primarily used in younger patients with fewer co-morbidities and less structural heart disease, limiting the general applicability of the device. S-ICDs achieve excellent rates of arrhythmia conversion and have demonstrated noninferiority to TV-ICDs in terms of complication rates in real-world studies. The objective of this review is to discuss the latest literature, including the UNTOUCHED and PRAETORIAN trials, and to address the risk of inappropriate shocks.

The potential impact of acute coronary syndromes on automatic sensing system in Subcutaneous-ICDs

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75 patients with ACS or CCS underwent S-ICD screening upon arrival and after PCI.

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Before PCI, STEMI patients had lower screening pass rates than NSTE-ACS ones

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STEMI was the only predictor of screening failure at multivariate regression analysis.

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Patient selection and dynamic device programming are fundamental in ischemic subjects

Background

The Subcutaneous-ICD (S-ICD) is emerging as a suitable option for most ICD candidates, however some open issues regarding the sensing algorithm still remain.

Objectives

We aimed to examine the performance of the S-ICD sensing algorithm in patients hospitalized for ST elevation myocardial infarction (STEMI), non ST elevation acute coronary syndrome (NSTE-ACS) or chronic coronary syndrome (CCS), before and after revascularization.

Methods

We performed a S-ICD automated screening on 75 patients, 21 hospitalized for STEMI, 23 for NSTE-ACS and 31 for CCS, before and after percutaneous revascularization, regardless their eligibility to ICD implantation.

Results

Patients did not differ in clinical, electrocardiographic and echocardiographic parameters. Rates of screening pass were significantly lower in STEMI patients compared to NSTE-ACS and CCS (5% vs 56.7% vs 81% respectively, p < .0001). The viability of the primary vector was lower in STEMI patients compared to NSTE-ACS and CCS (33% vs 56% vs 71%, p .027 respectively). After revascularization, there were no more significant differences between groups. Pairing subjects at baseline and after revascularization, STEMI subjects percentages of screening success were respectively 5% and 81% (p < .001) and the rates of primary vector viability were 33% and 81% (p .002). STEMI was the only independent predictor of screening failure at multivariate logistic regression analysis (odds ratio 10.68 confidence interval 2.77–41.38, p = .001)

Conclusion

The performance of the S-ICD and possible malfunction detections in the context of an acute ischemic event deserve further evaluation. Adequate patient selection and the development of dynamic device programming are warranted.

Predicting inappropriate S-ICD® episodes by simple 12-lead surface ECG parameters

AIMS

The present study aims at analyzing the role of a preimplantation 12-lead electrocardiogram (ECG) on the prediction of inappropriate S-ICD® episodes.

METHODS

N=116 screened patients (pts) with an S-ICD® and a follow-up of at least 6 months were included. A preimplantation 12-lead ECG (50 mm/s, 10 mm/mV) was analyzed with regard to QRS and T-wave amplitude, T wave concordance or discordance and QRS/T wave ratio in all 12 leads. To ensure an exact determination of parameters Datinf® Measure software was used. Results were correlated to the occurrence of oversensing of cardiac signals during follow-up.

RESULTS

N = 116 pts. (63,8% male, mean age 40,9 ± 15,5 years) were included (primary prevention in 47.4% of pts). The most frequent cardiac diseases were hypertrophic cardiomyopathy (HCM) in n = 25 (21,6%), electrical heart disease in n = 20 (17,2%), and dilated cardiomyopathy in n = 17 (14,7%). Mean follow-up was 740 ± 549 days. During follow- up n = 17 (14.7%) pts. experienced n = 27 inappropriate episodes due to T-wave oversensing. Besides HCM (OR 6.16, CI 1.79-21.15, p = 0.004) a discordance of QRS to T-wave in lead I (OR 6.5, CI 1.86-22.67, p = 0.003) was found to be a strong predictor for inappropriate shocks. In multivariate analysis the pts. with a combination of both had an 8.4-fold higher risk of misclassification of intracardiac signals (p = 0.003) with consecutive inappropriate therapy.

CONCLUSION

A discordance of QRS to T-wave in lead I turned out to be a strong predictor for future inappropriate shocks in a typical S-ICD® cohort with special impact on HCM pts.

Two Limitations of Subcutaneous Implantable Cardioverter Defibrillator in the Same Patient Warranting Its Explant

BACKGROUND A subcutaneous implantable cardioverter defibrillator (S-ICD) is preferred over a transvenous implantable cardioverter defibrillator (TV-ICD) in selected cases owing to a lower rate of lead-related complications such as infections and venous thrombosis. However, the S-ICD has its own limitations, including inappropriate shocks due to oversensed events, and the inability to treat ventricular tachycardia (VT) below a heart rate of 170 beats per minutes (bpm). We present a patient case which showed manifestations of both of these limitations, warranting explant of the device. CASE REPORT A 50-year-old man with a history of nonischemic cardiomyopathy and VT had a S-ICD placed at an outside facility. However, he continued to have VT despite on anti-arrhythmic drugs and required recurrent S-ICD shocks. Device interrogation showed that he was intermittently receiving appropriate shocks for slower VT (with a heart rate ranging from 150 bpm to 160 bpm) due to oversensing of T waves. However, treatment was delayed for other VT episodes owing to appropriate sensing and the patient's heart rate being below the lowest detection zone for S-ICD. Due to slower VT cycle length and frequent oversensed events, the S-ICD was ultimately replaced by a TV-ICD system. CONCLUSIONS This case report emphasizes the importance of S-ICD pre-implant vector screening and the need for paying attention to VT cycle length to prevent inappropriate device shocks and/or delayed therapies.

Brugada syndrome: Eligibility for subcutaneous implantable cardioverter-defibrillator after exercise stress test

INTRODUCTION

Brugada syndrome (BrS) is a channelopathy associated with ventricular arrhythmias and sudden cardiac death. In patients at high risk of sudden death, an implantable cardioverter-defibrillator is indicated. Subcutaneous implantable cardioverter-defibrillators (S-ICDs) are an alternative to transvenous systems, with reduced risk of infection and complications associated with system extraction or explantation.

OBJECTIVE

To test electrocardiographic eligibility for S-ICD placement after exercise stress testing (EST) in patients with BrS.

METHODS

The sample included 35 consecutive patients with BrS. Electrocardiographic eligibility was assessed using the Boston Scientific model 2889 EMBLEM™ S-ICD automated screening tool, in four phases: decubitus and orthostatism, and before and after EST. Those who had at least one acceptable vector in the four measurements were considered eligible.

RESULTS

In this study, 71.4% of patients were male and mean age was 53.86±12 years. In screening prior to EST, 14.3% of patients (n=5) were not eligible for an S-ICD. There was a statistically significant association between ineligibility and presence of complete right bundle branch block and history of syncope. After EST, 16.7% of initially eligible patients no longer had eligible vectors (n=5).

CONCLUSION

In this study, 16.7% of patients previously eligible for an S-ICD were no longer eligible after EST. This result demonstrates the importance of screening after EST in all patients with BrS and with indication for an S-ICD, and may influence decisions concerning which ICD to implant or whether to institute pharmacological measures that avoid inappropriate therapies.

A novel screening test for inappropriate shocks due to myopotentials from the subcutaneous implantable cardioverter–defibrillator

Background

The subcutaneous implantable cardioverter-defibrillator (S-ICD) is effective in preventing sudden cardiac death. Compared with transvenous ICDs, S-ICDs have a lower rate of inappropriate shocks (IASs) for supraventricular arrhythmias, but such shocks for T-wave oversensing (TWO) and extracardiac myopotentials are more common. No screening tests to identify patients at risk for IAS due to myopotential interference (MPI) currently are available.

Objective

The purpose of this study was to assess the efficacy of a tube exercise test (TET) developed to detect MPI post S-ICD implantation.

Methods

TET includes 3 different maneuvers using an exercise tube. S-ICD electrograms were recorded to assess MPI while patients performed each of the maneuvers.

Results

TET was performed in 43 patients, and MPI was observed in 12 patients (28%). In 10 of the 12 TET-positive patients, the positive vector corresponded with a vector that did not show TWO on standard S-ICD preoperative screening. During median follow-up of 672 days (interquartile range 465–805 days), 3 patients (7%) experienced IAS due to MPI. Importantly, the vector at the time of IAS in all 3 patients passed standard preoperative screening for TWO but was positive with TET. Sensitivity and specificity of TET were 100% and 78%, respectively, and positive and negative predictive values were 25% and 100%, respectively.

Conclusion

Postimplant screening for MPI identified patients at increased risk for IAS. TET may be helpful for guiding optimal programming to prevent IAS.

Use of pulsed electron avalanche knife (PEAK) PlasmaBlade™ in patients undergoing implantation of subcutaneous implantable cardioverter-defibrillator

Introduction

Surgical implantation of subcutaneous implantable cardioverter-defibrillators (S-ICD) requires preparation of a deeper and larger pocket. Infection and bleeding complications are reported, particularly in patients requiring antiplatelet therapy (APT) or being on oral anticoagulation (OAC), with rates up to 25%. The pulsed electron avalanche knife (PEAK) PlasmaBlade™ has been reported to reduce bleeding complications. The purpose of this study was to evaluate the safety and feasibility of a PEAK guided S-ICD implantation with respect to perioperative complications.

Methods and results

We enrolled 36 consecutive patients (75% male; mean age 52.1 ± 14.4 years) undergoing S-ICD implantation. Periprocedural safety endpoints comprised major complications including pocket hematomas, wound infections, bleeding (BARC ≥2) or events requiring interventions. Patients were divided into three groups according to management of their anticoagulation: i.) APT, n = 15 (41.7%); ii.) OAC, n = 10 patients (27.8%); iii.) none (neither OAC nor APT), n = 11 (30.6%). Mean procedure duration was 33.1 ± 13.4 min. Mean length of hospital stay was 3.3 ± 2.1 days. Overall analysis showed no differences between the 3 groups with respect to major complications, major bleeding episodes or other procedural parameters, beside a trend towards more minor hematomas in the OAC group (OAC: 22.2% vs. APT: 11.4% vs. none: 9.1%; p = 0.15).

Conclusion

The results of our pilot study suggest that intermuscular S-ICD implantation using PEAK is safe and potentially beneficial in patients receiving OAC or APT with respect to prevention of bleeding complications. These results support the rationale for large prospective controlled trials evaluating a beneficial effect of PEAK use in S-ICD implantation procedures.

Spotlight on S-ICD™ therapy: 10 years of clinical experience and innovation

Subcutaneous ICD (S-ICD™) therapy has been established in initial clinical trials and current international guideline recommendations for patients without demand for pacing, cardiac resynchronization, or antitachycardia pacing. The promising experience in ‘ideal’ S-ICD™ candidates increasingly encourages physicians to provide the benefits of S-ICD™ therapy to patients in clinical constellations beyond ‘classical’ indications of S-ICD™ therapy, which has led to a broadening of S-ICD™ indications in many centres. However, the decision for S-ICD™ implantation is still not covered by controlled randomized trials but rather relies on patient series or observational studies. Thus, this review intends to give a contemporary update on available empirical evidence data and technical advancements of S-ICD™ technology and sheds a spotlight on S-ICD™ therapy in recently discovered fields of indication beyond ideal preconditions. We discuss the eligibility for S-ICD™ therapy in Brugada syndrome as an example for an adverse and dynamic electrocardiographic pattern that challenges the S-ICD™ sensing and detection algorithms. Besides, the S-ICD™ performance and defibrillation efficacy in conditions of adverse structural remodelling as exemplified for hypertrophic cardiomyopathy is discussed. In addition, we review recent data on potential device interactions between S-ICD™ systems and other implantable cardio-active systems (e.g. pacemakers) including specific recommendations, how these could be prevented. Finally, we evaluate limitations of S-ICD™ therapy in adverse patient constitutions, like distinct obesity, and present contemporary strategies to assure proper S-ICD™ performance in these patients. Overall, the S-ICD™ performance is promising even for many patients, who may not be ‘classical’ candidates for this technology.

[Subcutaneous implantable cardioverter-defibrillator : Current status and perspectives]

The use of transvenous implantable cardioverter-defibrillators (ICD) for the prevention of sudden cardiac death has been proven in numerous randomized trials. By using a totally subcutaneous ICD (S-ICD) system, it is expected to ensure appropriate protection while avoiding long-term complications associated with transvenous leads, such as systemic infection and electrode dysfunction. Meanwhile, the safety and effectiveness of the S‑ICD has been substantiated by results of large registry studies. Based on the missing option for ventricular stimulation, corresponding recommendations have been integrated into current guidelines for certain patient populations. In the future, the issue of inadequate shocks caused by oversensing may be solved using advanced screening tools and new detection algorithms. Furthermore, a combination of subcutaneous ICD and LCP (leadless cardiac pacer) seems realistic to enable antibradycardia and antitachycardia ventricular pacing.

Evaluation of a novel automatic screening tool for determining eligibility for a subcutaneous implantable cardioverter-defibrillator

BACKGROUND

The manufacturer has developed a new ECG screening tool to determine eligibility for the subcutaneous ICD (S-ICD), the "automatic screening tool" (AST), which may render manual ECG-screening unnecessary. The aim of the study was to determine the eligibility for the S-ICD using two methods (manual ECG-screening versus AST) in different patient categories including patients with cardiomyopathy, congenital heart disease and inherited primary arrhythmia syndrome.

METHODS

We prospectively evaluated the ECG suitability for an S-ICD in consecutive patients at our outpatient clinic between February and June 2017. The primary endpoint of the study was ECG eligibility defined as at least 1 successful vector in both supine and sitting postures.

RESULTS

A total of 254 patients (167 men; mean age 45 ± 16 years) were screened using both methods. Overall, there was a high ECG eligibility using either method (93% versus 92%, P = 0.45). Overall agreement between both methods was 94%. Patients with hypertrophic cardiomyopathy (HCM) more often had a failed screening test using either test in comparison to the patients without HCM (manual: odds ratio [OR] 3.3, 95% confidence interval [CI] 1.2-9.3, P = 0.02; AST: OR 3.0, 95% CI 1.2-7.6, P = 0.02).

CONCLUSION

AST showed a high agreement with manual ECG-screening for S-ICD. Overall there was a high ECG eligibility for S-ICD, although patients with HCM had a lower passing rate irrespective of the screening method.