SMART pass will prevent inappropriate operation of S-ICD

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.

Lights and shadows of subcutaneous implantable cardioverter-defibrillator in Brugada syndrome

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.

A real‐world experience of subcutaneous and transvenous implantable cardiac defibrillators—comparison with the PRAETORIAN study

Background

Methods

Results

Conclusion

Usefulness of subcutaneous implantable cardioverter-defibrillator therapy in patients with Brugada syndrome

Implantable cardioverter-defibrillators (ICDs) are the main therapy to prevent sudden cardiac death in patients with Brugada syndrome (BrS). The subcutaneous ICD (S-ICD) can eliminate lead-associated complications compared with transvenous ICD (TV-ICD). However, S-ICD is susceptible to T-wave oversensing (TWOS) and may result in more frequent inappropriate shocks in patients with BrS. This study aimed to compare inappropriate shocks between TV-ICD and S-ICD in patients with BrS. We enrolled 32 patients with BrS (including one woman; mean age 52 ± 18 years) who were implanted with ICD (23 TV-ICDs and 9 S-ICDs) between January 2002 and November 2018 in Oita University Hospital. We carried out a standard surface electrocardiogram (ECG) screening tests in both supine and standing positions prior to S-ICD implantation. The patients received routine clinical review every month and device monitoring every 4 months. The period of follow-up was 129 ± 51 months. Six patients with BrS and TV-ICDs experienced inappropriate shocks (26%) with their ICD therapy. In contrast, two patients with BrS and S-ICDs experienced inappropriate shocks (22%). There was no significant difference between the two groups (P = 0.82). Although one case in the S-ICD group experienced TWOS-induced inappropriate shock, SMART Pass (new high-pass filter) prevented the subsequent recurrence of inappropriate shocks during ICD therapy. Our results suggest that S-ICD is not inferior to TV-ICD in the incidence of inappropriate shocks. SMART Pass may be a useful tool to prevent inappropriate ICD shocks by TWOS in patients with BrS.

Undetected displacement of a subcutaneous implantable cardioverter-defibrillator lead. importance of performing a chest X-ray during the first weeks post-implant: a case report

Background

In recent years, subcutaneous implantable cardioverter-defibrillator (S-ICD) implants have progressively increased and have been shown to be safe and highly successful, affording low reintervention rates regardless of the technique used.

Case summary

We present a case of S-ICD implantation in a patient diagnosed with idiopathic ventricular fibrillation. In the first follow-up consultation the patient showed appropriate detection parameters in the three configurations. However, chest X-ray revealed lead displacement with a tip migration from the manubrium area of the sternum to the xiphoid process.

Discussion

This case highlights the importance of performing at least one chest X-ray during the first weeks after S-ICD implantation, allowing the detection of a problem such as lead displacement, which can lead to undersensing of ventricular arrhythmias or S-ICD oversensing.

Impact of diabetes as a risk factor in patients undergoing subcutaneous implantable cardioverter defibrillator implantation: A single-centre study

INTRODUCTION

Patients with diabetes mellitus are known to carry an increased risk for surgical site infections and perioperative complications. The subcutaneous implantable cardioverter defibrillator is an established treatment option in patients at risk for sudden cardiac death especially with an increased risk for infection over time.

METHODS AND RESULTS

Forty-eight patients (mean age = 55.0 ± 21.3 years, 31.3% patients with diabetes mellitus, 75% male) who underwent consecutive subcutaneous implantable cardioverter defibrillator surgery between February 2016 and May 2019 were retrospectively analysed. Overall adverse events including relevant bleeding complications, any surgical wound problems and infections requiring reoperation or device malfunction were evaluated as primary combined safety endpoint. Patients with diabetes mellitus tended to be older with a higher body mass index compared to non-diabetes mellitus. Procedure duration and postsurgery hospital days were not different in diabetes mellitus versus non-diabetes mellitus patients. Analysis of the primary combined endpoint showed no significant difference but a trend towards higher event rates in the diabetes mellitus group (diabetes mellitus vs non-diabetes mellitus: 20% vs 12.1%, p = 0.119).

CONCLUSION

Diabetes mellitus is a frequent and relevant variable in patients undergoing subcutaneous implantable cardioverter defibrillator implantation represented by 31.3% in this consecutive cohort. Our results suggest that diabetes mellitus is not associated with a prolonged hospital stay or increased rate of periprocedural adverse events.

[Appropriate procedure for pacemaker and ICD malfunction]

Malfunctions in implanted pacemaker and defibrillator systems can affect all components of the device (battery, capacitor, central processing unit (CPU), connector, soldering points, electrodes). The resulting problems can manifest themselves as inadequate therapy, a lack of therapy despite the need for stimulation or shock release in case of ventricular tachyarrhythmia, or as an ineffective delivery of therapy. The high number of implanted pacemaker and defibrillator systems, the increased life expectancy and the technical progress of cardiac "device" therapy mean that the treating physician is confronted with increasingly complex problems in the follow-up. In addition to the knowledge of the basic function of these devices, a structured procedure to detect and treat malfunctions in a timely manner is required. In this review, frequent malfunctions of pacemaker and defibrillators are presented, individual problems are pointed out, and solutions and treatment options are shown.

Outcome differences and device performance of the subcutaneous ICD in patients with and without structural heart disease

BACKGROUND

The performance of the subcutaneous ICD (S-ICD™) has been described in different kinds of heart disease and has been proven to be an important advance in prevention of sudden cardiac death (SCD). While positive experiences with the S-ICD™ initially came from collectives of patients without structural heart diseases, positive results have also been collected from cohorts with structural heart disease.

MATERIALS AND METHODS

All S-ICD™ patients with either ischemic cardiomyopathy (ICM), dilated cardiomyopathy (DCM) or hypertrophic cardiomyopathy (HCM) as the main indication for ICD implantation (n = 144 patients) or electrical heart disease/idiopathic ventricular fibrillation (n = 83 patients) in our large-scaled single-center S-ICD™ registry were included in this study. Baseline characteristics, appropriate and inappropriate shocks, and complications were documented in a mean follow-up of 18 ± 15 months.

RESULTS

Baseline characteristics were significantly different between the two groups in most categories. In contrast, there was no difference concerning neither appropriate nor inappropriate shock delivery between the two groups. Also other outcome parameters such as need for surgical revisions and all-cause mortality did not differ. There was a significant difference between the first- and second-generation S-ICDs™ in inadequate shocks mainly driven by patients with HCM.

CONCLUSION

In our study, S-ICD™ performance was similar in patients with and without structural heart disease. Decision pro- or contra-S-ICD™ should be made rather on the basis of expected shock rate and probability of the need for future anti-tachycardia or anti-bradycardia pacing than in dependence of the underlying heart disease.