First use of cardiac contractility modulation (CCM) in a patient failing CRT therapy: clinical and technical aspects of combined therapies

Cardiac contractility modulating (CCM) signals delivered by the OPTIMIZER System are being investigated as a treatment for medically refractory heart failure. Previous chronic studies of CCM have excluded patients with prolonged QRS and a cardiac resynchronization therapy (CRT) device. However, symptoms persist in more than 25% of these CRT patients. CCM may offer a therapeutic option for these non-responders. Here we report the first use of CCM signals in a patient who did not respond to treatment with a CRT-D device. We show that the implantation is technically feasible, that the OPTIMIZER and CRT-D devices can coexist without interference and that acute haemodynamic and clinical improvements can be observed. The results suggest that systematic investigation of CCM treatment in CRT non-responders is warranted.     

The Entirely Subcutaneous Defibrillator (S-Icd): State of the Art and Selection of the Ideal Candidate

The traditional transvenous defibrillator has been one of the greatest advancement in Cardiology in the last 30 years and has demonstrated to reduce arrhythmic and total mortality in selected patients. However the traditional defibrillator can have a high price to pay in terms of complications, the “weakest link” being the transvenous/endocardial leads. The entirely subcutaneous defibrillator (S-ICD) has recently entered into the clinical scenario and represents a valid alternative to the transvenous device. S-ICD can provide substantial advantages, especially among some subgroups of patients (i.e. after device infection, in young patients and arrhythmogenic syndromes). However, given its characteristics, it is fundamental to choose patients that can benefit the most. In this review we will describe advantages and limitations of the S-ICD and point-out how to select the “ideal candidate” for the implantation.     

Therapie der chronischen Herzinsuffizienz durch kardiale Kontraktionsmodulation (CCM)

Cardiac contractility modulation (CCM) is a device therapy for patients with systolic heart failure. CCM therapy applies non-excitatory signals during the absolute refractory period of the heart cycle. It influences myocardial contractility by modulating the regulation of calcium cycling. CCM therapy has been proven to enhance peak VO(2), quality of life and exercise tolerance in patients with congestive heart failure. It can be used as an additional therapy to an implantable cardioverter defibrillator (ICD), if present. CCM therapy should be considered in symptomatic patients with congestive heart failure, a left ventricular ejection fraction ≤35% and NYHA class?II-III. Atrial fibrillation, high grade arrhythmias and an AV block of more than 300?ms represent contraindications. Patients with a left bundle branch block of >120?ms should be considered for the implantation of a biventricular ICD prior to implantation of a CCM device.     

One Indication for an Extravascular Cardiac Resynchronization Therapy Defibrillator: Lessons from a Combination Therapy Case with Epicardial Cardiac Resynchronization Therapy and a Subcutaneous Implantable Cardioverter Defibrillator

Extravascular cardiac resynchronization therapy (CRT) defibrillators (CRT-Ds) are ideal for recurrent blood stream infections. Furthermore, CRT is useful for patients intolerant to right ventricular (RV) pacing. The case was a 65-year-old man with a CRT-D who presented with a blood stream infection. Because he was hemodynamically unstable with temporary RV pacing, an epicardial CRT device was re-implanted concomitantly through a surgical procedure. After the operation, a subcutaneous implantable cardioverter defibrillator (S-ICD) was placed. However, not all pacing is eligible for S-ICD screening. Combination therapy with an epicardial CRT device and S-ICD might be an alternate option for cardiac surgery cases.     

Estudo Comparativo entre Receptores de Desfibriladores Subcutâneos e Transvenosos em Relação à Tolerância ao Procedimento de Implante e Percepção da Qualidade de Vida

BackgroundThe totally subcutaneous implantable cardioverter-defibrillator (S-ICD) is a safe alternative to the conventional transvenous ICD (TV-ICD) system to prevent sudden death.ObjectiveTo compare the impact of the type of ICD system and surgical technique on patients’ quality of life, as well as the severity of discomfort and pain, between S-ICD and TV-ICD recipients.MethodsConsecutively implanted patients with an S-ICD system were matched with patients with a TV-ICD system. In addition, patients undergoing S-ICD implantation after removal of a TV-ICD due to complications were included. Quality of life (measured with the 12-item short-form health survey) and severity of pain and discomfort were evaluated. Statistical significance was defined as p < 0.05.ResultsA total of 64 patients implanted with S-ICD or TV-ICD under local anesthesia and conscious sedation were analyzed. Patients with S-ICD and TV-ICD systems did not differ significantly in quality of life scores. S-ICD patients had a higher level of perioperative pain; no differences were found regarding severity of intraoperative pain. The magnitude of aesthetic discomfort and sleep disturbances did not differ between groups. An S-ICD was implanted in 7 additional patients after removal of a TV-ICD. All but one of these patients recommended the S-ICD system.ConclusionsThe type of ICD system and the surgical technique have negligible impact on patients’ quality of life. These results suggest that conscious sedation, provided by an experienced electrophysiology team, could be considered as an alternative to general anesthesia to manage patients undergoing S-ICD implantation.     

Subcutaneous chronic implantable defibrillation systems in humans

The recent introduction of subcutaneous implantable cardioverter defibrillator (S-ICD) has raised attention about the potential of this technology for clinical use in daily clinical practice. We review the methods and results of the four studies conducted in humans for approval of this innovative technology for daily practice. Two studies using a temporary S-ICD system (acute human studies) were conducted to search for an appropriate lead configuration and energy requirements. For this purpose, 4 S-ICD configurations were tested in 78 patients at the time of transvenous (TV)-ICD implantation. The optimal configuration was tested in 49 more patients to comparatively assess the subcutaneous defibrillation threshold (S-DFT) versus the standard TV-ICD. Long-term implants were evaluated in 55 patients using an implanted system (chronic human study). The acute humans studies led to an optimal S-ICD configuration comprising a parasternal electrode and left anterolateral thoracic pulse generator. Both configurations successfully terminated 98% of induced ventricular fibrillation (VF), but significantly higher energy levels were required with S-ICD than with TV-ICD systems (36.6?±?19.8 J vs. 11.1?±?8.5 J). In the chronic study, all 137 VF episodes induced at time of implant were detected with a 98% conversion rate. Two pocket infections and four lead revisions were required during 10?±?1 months of follow-up. During this period, survival was 98%, and 12 spontaneous ventricular tachyarrhythmias were detected and treated by the device. These data show that the S-ICD systems here consistently detected and converted VF induced at time of implant as well as sustained ventricular tachyarrhythmias occurring during follow-up (248).     

The Subcutaneous Defibrillator

OPINION STATEMENT: Prevention of sudden cardiac death (SCD) remains an important clinical problem. Currently, therapeutic goals for SCD prevention include identification of high risk patients and aggressively treating comorbidities underlying. However, many patients remain at increased risk despite optimal medical management (eg, coronary artery disease and cardiomyopathy) whereas others have nonmodifiable risk for sudden death (eg, arrhythmogenic right ventricular dysplasia/cardiomyopathy, Brugada syndrome, long QT syndrome, and hypertrophic cardiomyopathy). In such patients, device therapy with an implantable defibrillator remains the most effective therapy for SCD prevention. However, implantable cardioverter defibrillators (ICDs), which are typically implanted with at least 1 lead placed within the heart, are associated with risks related to device implantation, as well as the presence of chronic endovascular leads. The durability of chronic leads is variable and can require either new leads to be placed or require lead extraction, which is associated with significant morbidity and mortality. The recently developed subcutaneous ICD (S-ICD) does not rely on any component to be placed within the heart or vasculature and therefore may mitigate the risks associated with endovascular leads. Therefore, it may be preferred for patients who are young, have inherited channelopathies, are immunocompromised, have indwelling catheters, or in whom venous access is obstructed or unfavorable due to congenital heart disease. Though long-term data regarding S-ICD performance are not yet available it may prove to be an effective therapeutic option for prevention of SCD.     

Early Experience with the Subcutaneous ICD

The Subcutaneous Internal Cardiac Defibrillator (S-ICD) represents a major advance in the care of patients who have an indication for an internal cardiac defibrillator without pacing indications. Its main advantage is that it can deliver a shock to cardiovert ventricular arrhythmias utilising a tunnelled subcutaneous lead, negating the risks associated with conventional transvenous systems. Initial studies have shown comparable efficacy in cardioversion of induced and spontaneous ventricular tachycardia (VT) and ventricular fibrillation (VF) when compared to conventional transvenous systems. In addition, inappropriate shocks occurred in a similar percentage of patients to conventional ICD studies. Complication rates are low and relate largely to localised wound infections, treated successfully with antibiotics. The long term efficacy of the device is yet to be ascertained, however, a randomised trial & prospective registries are currently in progress to enable direct comparison with transvenous ICDs. This article summarises the early clinical experience and trials in the implantation of the S-ICD.     

Clinical effects of cardiac contractility modulation (CCM) as a treatment for chronic heart failure

Cardiac contractility modulation (CCM) signals are non-excitatory signals applied during the absolute refractory period that have been shown to enhance the strength of left ventricular contraction without increasing myocardial oxygen consumption in studies carried out in animals and humans with heart failure and reduced ejection fraction. Studies from myocardial tissue of animals and humans with heart failure suggest that the mechanisms of these effects is that CCM drives expression of many genes that are abnormally expressed in heart failure towards normal, including proteins involved with calcium cycling and the myocardial contractile machinery. Clinical studies have primarily focused on patients with normal QRS durations in view of the fact that cardiac resynchronization (CRT) is a viable option for patients with prolonged QRS duration. These studies show that CCM improves exercise tolerance as indexed by peak oxygen consumption (VO(2)) and quality of life indexed by the Minnesota Living with Heart Failure Questionnaire. The device is currently available for clinical use in countries recognizing the CE mark and is undergoing additional testing in the USA under a protocol approved by the Federal Drug Administration.     

Epicardial CRT-P- and S-ICD Implantation in a Young Patient with Persistent Left Superior Vena Cava

Persistent left superior vena cava is known to be a challenging anatomic abnormality for transvenous cardiac device implantation. In the a case of a young man presenting with dilative cardiomyopathy with severely impaired left ventricular ejection fraction (LVEF) and second-degree atrioventricular block (AV block), cardiac resynchronization therapy (CRT) with defibrillator (CRT-D) implantation was indicated. A transvenous approach was attempted, but placement of the right ventricular lead was not successful due to anatomic abnormalities. Therefore, epicardial CRT leads were implanted via a left mini-thoracotomy. For primary prevention of sudden death, the patient was also fitted with an additional subcutaneous implantable cardioverter defibrillator (S-ICD). Any cross-talk between the devices was ruled out both intraoperatively and by ergometry prior to discharge. The combination of epicardial CRT-P with S?ICD implantation might be a safe and effective alternative in patients with cardiac anatomic abnormalities.     

Mort subite du sujet jeune : le défibrillateur sous-cutané S-ICD est-il une solution alternative aux défibrillateurs conventionnels ?

Implantable cardioverter defibrillator (ICD) is well-recognized therapy to prevent sudden cardiac death. Classic ICD need the use of permanent endocavitary leads, which may cause serious troubles (lead dislodgement, ventricular perforation, lead infections, etc.). The subcutaneous implantable cardioverter defibrillator (S-ICD) is a new device provided by only a subcutaneous lead. It has been developed for the last five years and it is becoming at present a real alternative to classic ICD. We report a clinical case of a 34 y.o. woman who presented a sudden cardiac death and who benefited the implantation of this new technology. This paper deals with the potential indications, usefulness benefits, and problems of the S-ICD.     

Propofol dose and efficacy of defibrillation testing during implantation of subcutaneous implantable cardioverter-defibrillators: A retrospective,single center cohort study

Introduction

Defibrillation testing (DFT) is recommended during subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation. Previous studies analyzing the potential interference of propofol with defibrillation threshold are inconsistent. The purpose of this study was to analyze whether propofol affects DFT post S-ICD placement.

Methods

All patients with S-ICD implantation between 01/2017 and 11/2020 at the University Heart Center Freiburg were retrospectively analyzed. Two groups were generated depending on the success of the first shock during DFT. Implantation characteristics and dose of anesthetics were analyzed.

Results

In 12 of the included 80 (15%) patients, first shock during DFT failed. The absolute dose of propofol was significantly higher in patients with first shock failure (median 653 mg [IQR 503–855]) compared to patients with first shock termination (376 mg [200–600]; p = 0.027). Doses of opioids and midazolam as well as type of anesthesia did not differ between the groups. A multivariable binary logistic regression analysis confirmed an independent association of first shock termination and propofol dose (per 100 mg: OR 0.73 (95% CI: 0.56–0.95); p = 0.021).

Conclusion

There is an independent association of propofol dose and first shock failure in routine S-ICD defibrillation testing.     

Entirely subcutaneous defibrillator and complex congenital heart disease: Data on long-term clinical follow-up

AIM To describe the long-term follow-up of patients with complex congenital heart disease who underwent subcutaneous implantable cardiac defibrillator(S-ICD), focusing on local complications, appropriate and inappropriate shocks.METHODS Patients with complex congenital heart disease underwent S-ICD implant in two centers with the conventional technique. Data at follow-up were retrieved from clinical notes and institutional database. RESULTS Eight patients were implanted in two centres between 2010 and 2016. Median age at implant was 37.5 years(range 13-57). All patients who were deemed suitable for S-ICD implant passed the pre-procedural screening. Three patients were previously implanted with a antibradycardia device, one of whom with CRT. In one patient the device was explanted due to local infection. Duringthe total median follow-up of 874 d, one patient had an appropriate and one inappropriate shock triggered by fast atrial tachycardia. None of the patients had inappropriate shocks secondary to T wave oversensing or electrical interference with anti-bradycardia devices.CONCLUSION S-ICD appears to be effective and safe in patients with complex congenital heart disease.     

Acute and Long-term Results After Contemporary Subcutaneous Implantable Cardioverter-defibrillator Implantation: A Single-center Experience

Introduction and objectives

The subcutaneous implantable cardioverter-defibrillator (S-ICD) has emerged as an alternative to the transvenous defibrillator. The incidence of complications is similar, with inappropriate shocks (IS) being more frequent than those occurring with contemporary programming of transvenous defibrillators. Several improvements have been implemented after the S-ICD was approved for use in Europe in 2009. This study reports the results of S-ICD use in a single center, whose experience began late, at the end of 2013.

Implantation of Implantable Cardioverter Defibrillators in Kazakhstan

Background and Objectives:Implantation of implantable cardioverter-defibrillators (ICD) has increased significantly over the past decade. However, limited data exist regarding practices and policies of ICD implantations in Kazakhstan. We aimed to provide an overview of the current use of ICD in Kazakhstan.Methods:Using the Unified Healthcare Information System database of the entire Kazakh adult population, statistical and cost data of ICD implantations in 2017–2019 were evaluated. Cardiologists and electrophysiologists working in cardio surgery centers and departments were asked to go through an online survey focused on subcutaneous-ICD (S-ICD) experience.Results:Implantation of traditional transvenous cardioverter-defibrillators for residents of Kazakhstan is fully reimbursed. A total of 2,263 ICD interventions (2,252 new implantations and 11 reimplantations) were performed across the country during the study period. According to the tariffs approved by the Ministry of Health, the reimbursement cost for one ICD case is about 14,061.80 US dollars. The survey showed that only two hospitals have implanted S-ICDs. Among the main reasons why S-ICD is not widely used in the country the following were named: lack of trained staff (61.1% of respondents); the cost of device and lack of reimbursement (38.7%); and lack of pacing function (27.8%).Conclusion:The number of ICD implantation in Kazakhstan is steadily continuing to grow, although, compared to developed countries, the implantation rate especially for S-ICD remains low. There is a need in deliberate strategies to remove policy barriers for implementation the most innovative cardiac implantable electronic devices implantations such as S-ICD in the country.     

Komplett subkutaner Kardioverter-Defibrillator (S-ICD?)

The implantable cardioverter defibrillator (ICD) is an established therapy for patients at risk of sudden cardiac death. Nevertheless the endocardial electrode in conventional systems plays a major role in long-term complications (difficult removal, risk of endocarditis, etc.). The totally subcutaneous ICD (S-ICD?, Cameron Health, San Clemente, CA, USA) represents a new and particularly significant development in ICD therapy which, since it requires no electrode in or on the heart, results in significantly fewer perioperative and long-term complications (e.g., thromboembolism and endocarditis risk). Although we see an indication for primary and secondary prevention, patients need to be informed about the limited data from randomized trials with the S-ICD?. As there is no permanent pacing option, patients in whom a pacemaker is indicated are not appropriate candidates for S-ICD?. In addition, patients with ventricular tachycardias that can be terminated by antitachycardic pacing are not recommended for the device. In the present article, we report our initial experience with the 18 patients implanted with the S-ICD? to date, comment on the available studies and offer a critical perspective.     

Predictors of Subcutaneous Implantable Cardioverter-Defibrillator Shocks and Prognostic Impact in Patients With Structural Heart Disease

BackgroundIn this study we aimed to assess long-term outcomes in subcutaneous implantable cardioverter-defibrillator (S-ICD) recipients with structural heart disease by focussing especially on shock incidence, predictors, and associated prognoses.MethodsIn this multicenter registry?based study, we retrospectively included all patients who underwent S-ICD implantation at 3 tertiary centers. The prognostic impact of S-ICD shock was assessed with a composite outcome that included all-cause death and hospitalisation for heart failure.ResultsA total of 351 patients with underlying cardiomyopathy were included in the investigation. Using multivariable Fine and Gray regression models, secondary prevention, left ventricular ejection fraction (LVEF), conditional shock threshold, and QRS duration appeared to be independent predictors of appropriate S-ICD shock occurrence. In the multivariate Cox regression model adjusted for age, baseline LVEF, underlying cardiomyopathy subtype, New York Heart Association class, and appropriate shocks were significantly associated with increased composite prognostic outcome risk (hazard ratio [HR], 2.61; 95% confidence interval [CI], 1.21-5.65; P = 0.014), whereas inappropriate shocks were not (HR, 1.35; 95% CI, 0.75-4.48; P = 0.18). The analysis of each component of the composite prognostic outcome highlighted that the occurrence of appropriate shocks was associated with an increased risk of hospitalisation for heart failure (HR, 3.10; 95% CI, 1.26-7.58; P = 0.013) and a trend for mortality (HR, 2.19; 95% CI, 0.78-6.16; P = 0.14).ConclusionsAppropriate S-ICD shocks were associated with a 3-fold increase in acute heart failure admission, whereas inappropriate shocks were not. Conditional shock threshold programming is an independent predictor of S-ICD shock, and its prognostic impact should be investigated further in patients with structural heart disease.     

Security millimetre wave body scanner safe for patients with leadless pacemakers or subcutaneous implantable cardioverter-defibrillators

Purpose

This study was designed to evaluate the electromagnetic interference (EMI) effects and safety of the new security screening millimetre wave body scanners (MWBSs) for patients with rare cardiac implantable electronic devices (CIEDs).

Methods

We identified 73 patients with either entirely subcutaneous implantable cardioverter-defibrillators (S-ICD) or leadless pacemakers (LPM) attending routine device follow-up. CIED programming was optimised for the detection of EMI occurrence, and high-voltage therapy was disabled. Patients then underwent millimetre wave body scans under continuous ECG monitoring. Scanning was performed at the recommended distance as well as in close proximity to the scanner emulating accidental exposure. CIED function was observed for EMI effects.

Results

There were no episodes of inhibition of pacing in the leadless pacemaker subgroup, no oversensing in the S-ICD subgroup and no spontaneous device reprogramming in any group. There was no change in pacing or sensing thresholds, and S-ICD vector eligibility remained unchanged after scanning with the MWBS. No CIEDs were identified by the MWBS during the study.

Conclusion

No EMI events were detected during the use of MWBSs by patients with either S-ICDs or LPMs. This data should be reassuring for patients suggesting that they can undergo security body scans without worries or disclosure of their CIED status.

     

Improving left ventricular contraction by stimulation during the absolute refractory period. Cardiac contractility modulation

Cardiac contractility modulating (CCM) signals are nonexcitatory signals applied during the absolute refractory period and have been shown to enhance the strength of left ventricular contraction in studies performed in animals and humans with heart failure. In patients with congestive heart failure, improvement of exercise tolerance and quality of life have been shown. Recent studies from myocardial biopsies demonstrate that CCM treatment normalizes expression of many genes that are abnormally expressed in heart failure, including proteins involved with calcium cycling. These findings suggest that CCM might be an alternative or even additional electrical treatment option for patients with heart failure and normal QRS duration delivered by a pacemaker, e.g., a rechargeable device without any antibradycardiac or antitachycardiac function.