Wearable cardioverter-defibrillator in patients with a transient risk of sudden cardiac death: the WEARIT-France cohort study

Therapy duration and improvement of ventricular function in de novo heart failure: the Heart Failure Optimization study

BACKGROUND AND AIMS

In patients with de novo heart failure with reduced ejection fraction (HFrEF), improvement of left ventricular ejection fraction (LVEF) is expected to occur when started on guideline-recommended medical therapy. However, improvement may not be completed within 90 days.

METHODS

Patients with HFrEF and LVEF ≤ 35% prescribed a wearable cardioverter-defibrillator between 2017 and 2022 from 68 sites were enrolled, starting with a registry phase for 3 months and followed by a study phase up to 1 year. The primary endpoints were LVEF improvement > 35% between Days 90 and 180 following guideline-recommended medical therapy initiation and the percentage of target dose reached at Days 90 and 180.

RESULTS

A total of 598 patients with de novo HFrEF [59 years (interquartile range 51-68), 27% female] entered the study phase. During the first 180 days, a significant increase in dosage of beta-blockers, renin-angiotensin system inhibitors, and mineralocorticoid receptor antagonists was observed (P < .001). At Day 90, 46% [95% confidence interval (CI) 41%-50%] of study phase patients had LVEF improvement > 35%; 46% (95% CI 40%-52%) of those with persistently low LVEF at Day 90 had LVEF improvement > 35% by Day 180, increasing the total rate of improvement > 35% to 68% (95% CI 63%-72%). In 392 patients followed for 360 days, improvement > 35% was observed in 77% (95% CI 72%-81%) of the patients. Until Day 90, sustained ventricular tachyarrhythmias were observed in 24 wearable cardioverter-defibrillator carriers (1.8%). After 90 days, no sustained ventricular tachyarrhythmia occurred in wearable cardioverter-defibrillator carriers.

CONCLUSIONS

Continuous optimization of guideline-recommended medical therapy for at least 180 days in HFrEF is associated with additional LVEF improvement > 35%, allowing for better decision-making regarding preventive implantable cardioverter-defibrillator therapy.

Novel Medical Treatments and Devices for the Management of Heart Failure with Reduced Ejection Fraction

Heart failure (HF) is a growing issue in developed countries; it is often the result of underlying processes such as ischemia, hypertension, infiltrative diseases or even genetic abnormalities. The great majority of the affected patients present a reduced ejection fraction (≤40%), thereby falling under the name of "heart failure with reduced ejection fraction" (HFrEF). This condition represents a major threat for patients: it significantly affects life quality and carries an enormous burden on the whole healthcare system due to its high management costs. In the last decade, new medical treatments and devices have been developed in order to reduce HF hospitalizations and improve prognosis while reducing the overall mortality rate. Pharmacological therapy has significantly changed our perspective of this disease thanks to its ability of restoring ventricular function and reducing symptom severity, even in some dramatic contexts with an extensively diseased myocardium. Notably, medical therapy can sometimes be ineffective, and a tailored integration with device technologies is of pivotal importance. Not by chance, in recent years, cardiac implantable devices witnessed a significant improvement, thereby providing an irreplaceable resource for the management of HF. Some devices have the ability of assessing (CardioMEMS) or treating (ultrafiltration) fluid retention, while others recognize and treat life-threatening arrhythmias, even for a limited time frame (wearable cardioverter defibrillator). The present review article gives a comprehensive overview of the most recent and important findings that need to be considered in patients affected by HFrEF. Both novel medical treatments and devices are presented and discussed.

Expanded application of wearable cardioverter defibrillators beyond current guidelines: proposal for a European register explained through single clinical scenarios

The wearable cardioverter defibrillator (WCD) is becoming a more and more widely used instrument for the prevention of sudden cardiac death of patients either with a secondary prevention implantable cardioverter defibrillator indication or with a transient high risk of sudden cardiac death. Although clinical practice has demonstrated a benefit of protecting patients for a period as long as 3-6 months with such devices, the current European guidelines concerning ventricular arrhythmias and sudden cardiac death are still extremely restrictive in the patient selection in part because of the costs derived from such a prevention device, in part because of the lack of robust randomised trials.To illustrate expanded use cases for the WCD, four real-life clinical cases are presented where patients received the device slightly outside the established guidelines. These cases demonstrate the broader utility of WCDs in situations involving acute myocarditis, thyrotoxicosis, pre-excited atrial fibrillation and awaiting staging/prognosis of a lung tumour. The findings prompt expansion of the existing guidelines for WCD use to efficiently protect more patients whose risk of arrhythmic cardiac death is transient or uncertain. This could be achieved by establishing a European register of the patients who receive a WCD for further analysis.

The Role of the Wearable Defibrillator in Heart Failure

PURPOSE OF REVIEW

Wearable cardioverter defibrillators (WCDs) have been developed as a temporary measure for protecting patients at risk for sudden cardiac death that do not meet the indication for implantable cardioverter defibrillator (ICD), most notably in the early stages of heart failure with reduced ejection fraction before reassessment of their left ventricular ejection fraction. In this review, we report available evidence in the literature and guidelines regarding WCD use in order to try to define the role WCDs may have in heart failure.

RECENT FINDINGS

In the last decade, most observational studies found WCDs to be both safe and effective in terminating ventricular arrhythmias in various indications, mostly centered around heart failure with reduced ejection fraction. The only available randomized controlled trial using WCD did not however show a benefit on patients' survival. Hence, recent guidelines only recommended its use in limited indications. Recent data also suggest a possible interest of WCD in monitoring patients, a finding that may prove useful in the context of new-onset heart failure. Data regarding WCD benefit is scarce, and definitive conclusions on its utility are hard to draw. In the context of heart failure, and particularly new-onset heart failure, WCD might find a role in a global comprehensive management of the disease, both acting as an educational tool, a monitoring tool, and, most importantly, a safe and effective tool in preventing sudden cardiac death. The low level of evidence however invites caution, and the decision of prescribing a WCD needs to be individualized and thoroughly discussed with the patient whose compliance is key with this device.

A novel artificial intelligence based algorithm to reduce wearable cardioverter-defibrillator alarms

BACKGROUND

The wearable cardioverter defibrillator (WCD) is an important tool in mitigating sudden cardiac death (SCD). The WCD provides patient alarms for detected arrhythmias or electrical noise/artifact. Some patients experience frequent alarms for artifact. We sought to evaluate the effects of a novel artificial intelligence algorithm to reduce alarms related to electrical noise or artifact (advanced arrhythmia discrimination algorithm, AArD).

METHODS

A retrospective review of a large commercial database of prescribed WCD. Patients prescribed the WCD during the years 2017 (discrimination algorithm, DA group) or during 2019 (advanced arrhythmia discrimination algorithm, AArD) were analyzed. A total of 96,000 patients were sampled, 48,000 in the control group (using standard direct algorithm, DA) and compared to 48,000 in the intervention AArD (4000 per group per month) for 12 months. The AArD further discriminates ECG signals based on a machine-learning algorithm utilizing intensity and frequency beyond the standard DA. Outcomes regarding alarms, arrhythmias, and safety were analyzed.

RESULTS

The AArD algorithm was associated with a significant decrease in frequency of alarms over the course of WCD use; 54% of patients in the AARD versus 27% of DA had 0 alarms (P < .001). In the entire cohort, there was a 56% relative reduction in alarms with the use of AArD. Appropriate arrhythmia treatment time was not significantly different between the groups (44 s DA vs 45 s AArD [p = ns]).

CONCLUSIONS

A novel artificial intelligence algorithm reduces alarms without delaying appropriate therapy for VT/VF. These changes may improve compliance and quality of life in patients with a WCD.

Revascularization and Left Ventricular Dysfunction for ICD Eligibility

Common triggers for sudden cardiac death (SCD) are transient ischemia, hemodynamic fluctuations, neurocardiovascular influences, and environmental factors. SCD occurs rapidly when sinus rhythm degenerates into ventricular tachycardia (VT) and/or ventricular fibrillation (VF), followed by asystole. Such progressive worsening of the cardiac rhythm is in most cases observed in the setting of ischemic heart disease and often associated with advanced left ventricular (LV) impairment. Revascularization prevents negative outcomes including SCD and heart failure (HF) due to LV dysfunction (LVD). The implantable cardioverter-defibrillator (ICD) on top of medical therapy is superior to antiarrhythmic drugs for patients with LVD and VT/VF. The beneficial effects of ICD have been demonstrated in primary prevention of SCD as well. However, yet debated is the temporal management for patients with LVD who are eligible to ICD prior to revascularization, either through percutaneous or surgical approach. Restoration of coronary blood flow has a dramatic impact on adverse LV remodeling, while it requires aggressive long-term antiplatelet therapy, which might increase complication for eventual ICD procedure when percutaneous strategy is pursued; on the other hand, when LV and/or multiorgan dysfunction is present and coronary artery bypass grafting is chosen, the overall risk is augmented, mostly in HF patients. The aims of this review are to describe the pathophysiologic benefits of revascularization, the studies addressing percutaneous, surgical or no revascularization and ICD implantation, as well as emerging defibrillation strategies for patients deemed at transient risk of SCD and/or at higher risk for transvenous ICD implantation.

The Lancet Commission to reduce the global burden of sudden cardiac death: a call for multidisciplinary action

Despite major advancements in cardiovascular medicine, sudden cardiac death (SCD) continues to be an enormous medical and societal challenge, claiming millions of lives every year. Efforts to prevent SCD are hampered by imperfect risk prediction and inadequate solutions to specifically address arrhythmogenesis. Although resuscitation strategies have witnessed substantial evolution, there is a need to strengthen the organisation of community interventions and emergency medical systems across varied locations and health-care structures. With all the technological and medical advances of the 21st century, the fact that survival from sudden cardiac arrest (SCA) remains lower than 10% in most parts of the world is unacceptable. Recognising this urgent need, the Lancet Commission on SCD was constituted, bringing together 30 international experts in varied disciplines. Consistent progress in tackling SCD will require a completely revamped approach to SCD prevention, with wide-sweeping policy changes that will empower the development of both governmental and community-based programmes to maximise survival from SCA, and to comprehensively attend to survivors and decedents' families after the event. International collaborative efforts that maximally leverage and connect the expertise of various research organisations will need to be prioritised to properly address identified gaps. The Commission places substantial emphasis on the need to develop a multidisciplinary strategy that encompasses all aspects of SCD prevention and treatment. The Commission provides a critical assessment of the current scientific efforts in the field, and puts forth key recommendations to challenge, activate, and intensify efforts by both the scientific and global community with new directions, research, and innovation to reduce the burden of SCD worldwide.

Risk stratification of sudden cardiac death: a review

Sudden cardiac death (SCD) is responsible for several millions of deaths every year and remains a major health problem. To reduce this burden, diagnosing and identification of high-risk individuals and disease-specific risk stratification are essential. Treatment strategies include treatment of the underlying disease with lifestyle advice and drugs and decisions to implant a primary prevention implantable cardioverter-defibrillator (ICD) and perform ablation of the ventricles and novel treatment modalities such as left cardiac sympathetic denervation in rare specific primary electric diseases such as long QT syndrome and catecholaminergic polymorphic ventricular tachycardia. This review summarizes the current knowledge on SCD risk according to underlying heart disease and discusses the future of SCD prevention.

Does Patient Compliance Influence Wearable Cardioverter Defibrillator Effectiveness? A Single-Center Experience

The study was designed to assess patient adherence to wearable cardioverter defibrillator as an indicator of device effectiveness. The patient training is not widely properly standardized. We enrolled 25 patients with a wearable cardioverter defibrillator to prevent sudden cardiac death between June 2020 and August 2022. Among them, 84% were male with a median age of 63.6 years. The indication was an ischemic (44%) and a non-ischemic (56%) disease. The patients were followed-up until the decision to upgrade to an implantable device was taken. We trained the patients according to our suggested protocol. The median wear time was 90 days, and the median daily wear time was 23.5 h, similar throughout sex, age, and indication groups. In total, 24% of the participants underwent cardioverter defibrillator implantation. Between the device-implanted and non-implanted groups, left ventricular ejection fraction and left ventricular indexed end-diastolic volume were significantly different (EF 35.8 ± 12 vs. 46.4 ± 8.5%, p = 0.028, iEDV 108 ± 52 vs. 70.7 ± 21.1 mL/m2, p = 0.024). We did not find any differences in cardiac magnetic resonance data, even though all patients who underwent device implantation had late gadolinium enhancement spots. Our results support standardized patient training to obtain great patient adherence to the instructions to the wearable device and therefore its effectiveness.

Dynamic changes in nocturnal heart rate predict short-term cardiovascular events in patients using the wearable cardioverter-defibrillator: from the WEARIT-France cohort study

AIMS

While elevated resting heart rate measured at a single point of time has been associated with cardiovascular outcomes, utility of continuous monitoring of nocturnal heart rate (NHR) has never been evaluated. We hypothesized that dynamic NHR changes may predict, at short term, impending cardiovascular events in patients equipped with a wearable cardioverter-defibrillator (WCD).

METHODS AND RESULTS

The WEARIT-France prospective cohort study enrolled heart failure patients with WCD between 2014 and 2018. Night-time was defined as midnight to 7 a.m. NHR initial trajectories were classified into four categories based on mean NHR in the first week (High/Low) and NHR evolution over the second week (Up/Down) of WCD use. The primary endpoint was a composite of cardiovascular death and heart failure hospitalization. A total of 1013 [61 (interquartile range, IQR 53-68) years, 16% women, left ventricular ejection fraction 26% (IQR 22-30)] were included. During a median WCD wear duration of 68 (IQR 44-90) days, 58 patients (6%) experienced 69 events. After considering potential confounders, High-Up NHR trajectory was significantly associated with the primary endpoint compared to Low-Down [adjusted hazard ratio (HR) 6.08, 95% confidence interval (CI) 2.56-14.45, P < 0.001]. Additionally, a rise of >5 bpm in weekly average NHR from the preceding week was associated with 2.5 higher composite event risk (HR 2.51, 95% CI 1.22-5.18, P = 0.012) as well as total mortality (HR 11.21, 95% CI 3.55-35.37, P < 0.001) and cardiovascular hospitalization (HR 2.70, 95% CI 1.51-4.82, P < 0.001).

CONCLUSION

Dynamic monitoring of NHR may allow timely identification of impending cardiovascular events, with the potential for 'pre-emptive' action.

REGISTRATION NUMBER

Clinical Trials.gov Identifier: NCT03319160.

Assessing physical activity with the wearable cardioverter defibrillator in patients with newly diagnosed heart failure

Background

The wearable cardioverter defibrillator (WCD), (LifeVest, ZOLL, Pittsburgh, PA, USA) is a medical device designed for the temporary detection and treatment of malignant ventricular tachyarrhythmias. WCD telemonitoring features enable the evaluation of the physical activity (PhA) of the patients. We sought to assess with the WCD the PhA of patients with newly diagnosed heart failure.

Methods

We collected and analyzed the data of all patients treated with the WCD in our clinic. Patients with newly diagnosed ischemic, or non-ischemic cardiomyopathy and severely reduced ejection fraction, who were treated with the WCD for at least 28 consecutive days and had a compliance of at least 18 h the day were included.

Results

Seventy-seven patients were eligible for analysis. Thirty-seven patients suffered from ischemic and 40 from non-ischemic heart disease. The average days the WCD was carried was 77.3 ± 44.6 days and the mean wearing time was 22.8 ± 2.1 h. The patients showed significantly increased PhA measured by daily steps between the first two and the last two weeks (Mean steps in the first 2 weeks: 4,952.6 ± 3,052.7 vs. mean steps in the last 2 weeks: 6,119.6 ± 3,776.2, p-value:  < 0.001). In the end of the surveillance period an increase of the ejection fraction was observed (LVEF-before: 25.8 ± 6.6% vs. LVEF-after: 37.5 ± 10.6%, p < 0.001). Improvement of the EF did not correlate with the improvement of PhA.

Conclusion

The WCD provides useful information regarding patient PhA and may be additionally utilized for early heart failure treatment adjustment.

ANMCO position paper: guide to the appropriate use of the wearable cardioverter defibrillator in clinical practice for patients at high transient risk of sudden cardiac death

Extended risk stratification and optimal management of patients with a permanently increased risk of sudden cardiac death (SCD) are becoming increasingly important. There are several clinical conditions where the risk of arrhythmic death is present albeit only transient. As an example, patients with depressed left ventricular function have a high risk of SCD that may be only transient if there will be a significant recovery of function. It is important to protect the patients while receiving and titrating to the optimal dose the recommended drugs that may lead to an improved left ventricular function. In several other conditions, a transient risk of SCD can be observed even if the left ventricular function is not compromised. Examples are patients with acute myocarditis, during the diagnostic work-up of some arrhythmic conditions or after extraction of infected catheters while eradicating the associated infection. In all these conditions, it is important to offer a protection to these patients. The wearable cardioverter defibrillator (WCD) is of particular importance as a temporary non-invasive technology for both arrhythmia monitoring and therapy in patients with increased risk of SCD. Previous studies have shown the WCD to be an effective and safe therapy for the prevention of SCD caused by ventricular tachycardia/fibrillation. The aim of this ANMCO position paper is to provide a recommendation for clinical utilization of the WCD in Italy, based upon current data and international guidelines. In this document, we will review the WCD functionality, indications, clinical evidence, and guideline recommendations. Finally, a recommendation for the utilization of the WCD in routine clinical practice will be presented, in order to provide physicians with a practical guidance for SCD risk stratification in patients who may benefit from this device.

Causes and Clinical Consequences of Inappropriate Shocks Experienced by Patients Wearing a Cardioverter-Defibrillator

BACKGROUND

The LifeVest® wearable cardioverter-defibrillator (WCD) prevents sudden cardiac death in at-risk patients who are not candidates for an implantable defibrillator. The WCD's safety and efficacy may be impacted by inappropriate shocks (IAS).

OBJECTIVE

Assess causes and clinical consequences of WCD inappropriate shocks in survivors of IAS events.

METHODS

The FDA Manufacturers and User Facility Device Experience (MAUDE) database was searched for IAS adverse events (AE) that were reported during 2021 and 2022.

RESULTS

A total of 2,568 IAS-AE were found (average # IAS/event: 1.5±1.9; range: 1-48). IAS were caused by tachycardias (1,255, 48.9%), motion artifacts (840, 32.7%), and oversensing (OS) of low-level electrical signals (473, 18.4%) (p<0.001). Tachycardias included atrial fibrillation (AF; 828,32.2%), supraventricular tachycardia (SVT; 333,13.0%), and non-sustained ventricular tachycardia/fibrillation (NSVT/VF; 87, 3.4%). Activities responsible for motion-induced IAS included riding a motorcycle, lawnmower, or tractor (n=128). IAS induced sustained VT or VF in 19 patients that were subsequently terminated by appropriate WCD shocks.Thirty patients fell and suffered physical injuries. Conscious patients (n=1905) did not use the response buttons to abort shocks (47.9%) or used them improperly (20.2%). IAS resulted in 1,190 emergency room visits or hospitalizations, and 17.3% (421/2440) of patients discontinued the WCD after experiencing IAS, especially multiple IAS.

CONCLUSIONS

The LifeVest WCD may deliver IAS caused by AF, SVT, NSVT/VF, motion artifacts and oversensing of electrical signals. These shocks may be arrhythmogenic, result in injuries, precipitate WCD discontinuation, and they consume medical resources. Improved WCD sensing, rhythm discrimination, and methods to abort IAS are needed.

Sudden Cardiac Death in Ischaemic Cardiomyopathy and the Primary Prevention ICD: Time for a More a Personalised Approach?

Guidelines recommend primary prevention implantable cardioverter defibrillator (PPICD) for left ventricular ejection fraction (LVEF) <35% only after 3 months of optimal medical therapy (OMT) or 6 weeks after acute MI with persistent LVEF dysfunction. A 73-year-old woman presented with decompensated heart failure secondary to ischaemic cardiomyopathy. Severe coronary disease with sufficient dysfunctional myocardial segments on cardiac MRI suggested potential benefit from revascularisation. Following discussion with the heart team, she underwent percutaneous coronary intervention (PCI). PPICD implantation was deferred as per guideline recommendations. However, 20 days post-PCI, the patient died from malignant ventricular arrhythmia captured on a Holter monitor. This case demonstrates that some high-risk patients may not receive a potentially life-saving PPICD if guidelines are stringently adhered to. We highlight evidence that LVEF alone is of limited value in a risk assessment of arrhythmogenic death, and postulate that a more personalised ICD prescription should be considered using scar characteristics on cardiac MRI to prompt upstream ICD implantation in high-risk patients.

Wearable cardioverter defibrillator for preventing sudden cardiac death in patients at risk: An updated systematic review of comparative effectiveness and safety

Objectives

To synthesise the available evidence of wearable cardioverter defibrillator (WCD) therapy as an add-on measure to optimal medical therapy (OMT) or as a replacement of hospital stay.

Methods

An update systematic review (SR) of comparative effectiveness and safety of WCD therapy was conducted. We included randomised controlled trials (RCT), prospective comparative studies and prospective uncontrolled studies with at least 100 patients. A narrative synthesis of the evidence was conducted.

Results

One RCT (n = 2348) and further eleven observational studies (n = 5345) fulfilled our inclusion criteria. In the only available RCT, the use of the WCD was not statistically associated with a clinical benefit on arrhythmic mortality in post-myocardial infarction (MI) patients with an ejection fraction of ≤35%. The compliance with WCD therapy was low in the RCT and high in observational studies, with ten observational studies reporting on a daily wear time between 20 and 23.5 h. The range of percentage of patients receiving at least one appropriate shock was 1-4.8% and the rate of first shock success was reported to be 100% in three studies. Serious adverse events (SAEs) such as inappropriate shocks occurred rarely, with between 0% and 2% of patients being inappropriately shocked within ten observational studies. In one of the observational studies, two patients (2%) were allergic to nickel developing skin rash and false alarms occurred in 58 patients (57%) in this study. Another registry study (n = 448) reported milder AEs, such as dermatitis and pressure marks, occurring in 0.9% and 0.2% of enrolled patients, respectively.

Conclusion

The only available RCT failed to show superiority of add-on use of WCD in post MI patients. Observational evidence shows that the compliance with WCD is good, but the evidence is afflicted with selection bias and the inclusion of diverse mixed patient populations diluting the ability to draw indication-specific conclusions on the utility of the device. More comparative data is needed to justify continuing or expanding use of WCD therapy.

Age differences of patients treated with wearable cardioverter defibrillator: Data from a multicentre registry

BACKGROUND

Wearable cardioverter defibrillators (WCD) are used as a 'bridging' technology in patients, who are temporarily at high risk for sudden cardiac death (SCD). Several factors should be taken into consideration, for example patient selection, compliance and optimal drug treatment, when WCD is prescribed. We aimed to present real-world data from seven centres from Germany and Switzerland according to age differences regarding the outcome, prognosis, WCD data and compliance.

MATERIALS AND METHODS

Between 04/2012 and 03/2021, 1105 patients were included in this registry. Outcome data according to age differences (old ≥45 years compared to young <45 years) were analysed. At young age, WCDs were more often prescribed due to congenital heart disease and myocarditis. On the other hand, ischaemic cardiomyopathy (ICM) was more present in older patients. Wear days of WCD were similar between both groups (p = .115). In addition, during the WCD use, documented arrhythmic life-threatening events were comparable [sustained ventricular tachycardia: 5.8% vs. 7.7%, ventricular fibrillation (VF) .5% vs. .6%] and consequently the rate of appropriate shocks was similar between both groups. Left ventricular ejection fraction improvement was documented over follow-up with a better improvement in younger patients as compared to older patients (77% vs. 63%, p = .002). In addition, at baseline, the rate of atrial fibrillation was significantly higher in the older age group (23% vs. 8%; p = .001). The rate of permanent cardiac implantable electronic device implantation (CiED) was lower in the younger group (25% vs. 36%, p = .05). The compliance rate defined as wearing WCD at least 20 h per day was significantly lower in young patients compared to old patients (68.9% vs. 80.9%, p < .001). During the follow-up, no significant difference regarding all-cause mortality or arrhythmic death was documented in both groups. A low compliance rate of wearing WCD is predicted by young patients and patients suffering from non-ischaemic cardiomyopathies.

CONCLUSION

Although the compliance rate in different age groups is high, the average wear hours tended to be lower in young patients compared to older patients. The clinical events were similar in younger patients compared to older patients.

Patient-reported outcomes using a wearable cardioverter-defibrillator: results from a systematic review

OBJECTIVES

The aim of this study was to assess the effect of the wearable cardioverter-defibrillator (WCD) on patient-reported outcomes (PRO) in adult patients with high risk for sudden cardiac arrest.

METHODS

We performed a systematic literature search in Medline (via PubMed) and Cochrane Library in February 2022 and included studies with a study population ≥18 years and prescribed WCD. PRO include health-related quality of life (QoL), symptoms, utilities, or satisfaction ratings. Study selection was done by two reviewers independently using predefined inclusion and exclusion criteria. Quality assessment of studies as well as data extraction was performed by one author and approved by a second author. Results of the included studies are presented quantitatively.

RESULTS

One randomized controlled trial (RCT), one comparative non-randomized trial, and three single-arm trials were included. QoL was assessed in four studies, but with different assessment tools. One study additionally evaluated the change in depressive symptoms and anxiety and one study focused on acceptability of WCD but evaluated items that are closely related to QoL. Results of the RCT show no statistically significant difference in QoL assessed by SF-36 and EQ-5D comparing WCD and Guideline-Directed Medical Therapy (GDMT) versus GDMT alone. One comparative study reports an improvement in depressive symptoms and anxiety within groups but no significant difference between groups. Further, one single-arm study reported improvement in QoL between baseline and day 90 and day 180.

CONCLUSIONS

The available evidence demonstrates that the usage of WCD is not affecting PRO, like QoL, depressive symptoms or anxiety negatively.

Defibrillation effectiveness and safety of the shock waveform used in a contemporary wearable cardioverter defibrillator: Results from animal and human studies

INTRODUCTION

The wearable cardioverter defibrillator (WCD) is used to protect patients at risk for sudden cardiac arrest. We examined defibrillation efficacy and safety of a biphasic truncated exponential waveform designed for use in a contemporary WCD in three animal studies and a human study.

METHODS

Animal (swine) studies: #1: Efficacy comparison of a 170J BTE waveform (SHOCK A) to a 150J BTE waveform (SHOCK B) that approximates another commercially available waveform. Primary endpoint first shock success rate. #2: Efficacy comparison of the two waveforms at attenuated charge voltages in swine at three prespecified impedances. Primary endpoint first shock success rate. #3: Safety comparison of SHOCK A and SHOCK B in swine. Primary endpoint cardiac biomarker level changes baseline to 6 and 24 hours post-shock. Human Study: Efficacy comparison of SHOCK A to prespecified goal and safety evaluation. Primary endpoint cumulative first and second shock success rate. Safety endpoint adverse events.

RESULTS

Animal Studies #1: 120 VF episodes in six swine. First shock success rates for SHOCK A and SHOCK B were 100%; SHOCK A non-inferior to SHOCK B (entire 95% CI of rate difference above -10% margin, p < .001). #2: 2,160 VF episodes in thirty-six swine. Attenuated SHOCK A was non-inferior to attenuated SHOCK B at each impedance (entire 95% CI of rate difference above -10% margin, p < .001). #3: Ten swine, five shocked five times each with SHOCK A, five shocked five times each with SHOCK B. No significant difference in troponin I (p = 0.658) or creatine phosphokinase (p = 0.855) changes from baseline between SHOCK A and SHOCK B. Human Study: Thirteen patients, 100% VF conversion rate. Mild skin irritation from adhesive defibrillation pads in three patients.

CONCLUSIONS

The BTE waveform effectively and safely terminated induced VF in swine and a small sample in humans.

TRIAL REGISTRATION

Human study clinical trial registration: URL: https://clinicaltrials.gov; Unique identifier: NCT04132466.

ECG as a risk stratification tool in patients with wearable cardioverter-defibrillator

BACKGROUND

The wearable cardioverter defibrillator (WCD) is increasingly used in patients at elevated risk for ventricular arrhythmias but not fulfilling the indications for an implantable cardioverter defibrillator (ICD). Currently, there is an insufficient risk prediction of fatal arrhythmias in patients at risk. In this study, we assessed the prognostic role of baseline electrocardiogram (ECG) in WCD patients.

METHODS

WCD patients from diverse clinical institutions in Germany (n = 227) were retrospectively enrolled and investigated for the incidences of death or ventricular arrhythmias during WCD wearing. In addition, the widely accepted ECG predictors of adverse outcome were analyzed in patients with arrhythmic events.

RESULTS

Life-threatening arrhythmias occurred in 22 (9.7 %) patients, mostly in subjects with ischemic heart disease (15 of 22). There was no difference in baseline left ventricular ejection fraction (LVEF) in subjects with and without arrhythmic events (31.3 ± 7.9 % vs. 32.6 ± 8.3 %; p = 0,24). Patients with arrhythmia exhibited significantly longer QRS duration (109.5 ± 23.1 ms vs. 100.6 ± 22.3 ms, p = 0,04), Tpeak-Tend (Tp-e) (103.1 ± 15.6 ms vs. 93.2 ± 19.2 ms, p = 0,01) and QTc (475.0 ± 60.0 ms vs. 429.6 ± 59.4 ms, p < 0,001) intervals. In contrast, no significant differences were found for incidences of fragmented QRS (27.3 % vs. 24 %, p = 0.79) and inverted/biphasic T-waves (16.6 % vs. 22.7 %, p = 0,55). In multivariate regression analysis both Tp-e (HR 1.03; 95 % CI 1.001-1.057; p = 0.02) and QTc (HR 1.02; 95 % CI 1.006-1.026; p < 0.001) were identified as independent predictors of ventricular arrhythmias. After WCD use, the prophylactic ICD was indicated in 76 patients (33 %) with uneventful clinical course but persistent LVEF ≤35 %. The ECG analysis in these subjects did not reveal any relevant changes in arrhythmogenesis markers.

CONCLUSIONS

ECG repolarization markers Tp-e and QTc are associated with malignant arrhythmias in WCD patients and may be used - in addition to other established risk markers - to identify appropriate patients for ICD implantation.

Sex differences and adherence of patients treated with wearable cardioverter-defibrillator: insights from an international multicenter register

AIMS

Treatment with the wearable cardioverter defibrillator (WCD) may protect against sudden cardiac death (SCD) as a bridging therapy until a cardioverter-defibrillator may be implanted. We analyzed in a multicenter setting a consecutive patient cohort wearing WCD to explore sex differences.

METHODS AND RESULTS

We analyzed 708 consecutive patients, 579 (81.8%) from whom were males and 129 (18.2%) females (age, 60.5±14 vs. 61.6±17 years old; p=0.44). While the rate of ischemic cardiomyopathy (ICM) as a cause of prescription of WCD was significantly higher in males as compared to females (42.7% vs. 26.4%; p=0.001), females received it more frequently due to non-ischemic cardiomyopathy (NICM) (55.8% vs. 42.7%); p=0.009). The wear time of WCD was equivalent in both groups (21.1±4.3 hours/days in males vs. 21.5±4.4 hours/days in females; p=0.27; and 62.6±44.3 days in males vs. 56.5±39 days in females; p=0.15). Mortality was comparable in both groups at 2-year-follow-up (6.8% in males vs. 9.7% in females; p=0.55). Appropriate WCD shocks and the incidence of ICD implantations were similar in both groups (2.4% in males vs. 3.9% in females; p=0.07) (35.1% in males vs. 31.8% in females; p=0.37), respectively. In age tertile analysis, compliance was observed more in 73-91 years old group as compared to 14-51 years old group (87.8% vs. 68.3%; p<0.001).

CONCLUSION

Compliance for wearing WCD was excellent regardless of sex. Furthermore, mortality and the incidence of ICD implantations were comparable in both sexes. Appropriate WCD shocks were similar in both sexes. This article is protected by copyright. All rights reserved.

The value of wearable cardioverter defibrillator in adult patients with recent myocardial infarction: Economic and clinical implications from a health technology assessment perspective

AIMS

Sudden cardiac death (SCD) causes high mortality and substantial societal burdens for healthcare systems (HSs). The risk of SCD is significantly increased in patients with reduced left ventricular ejection fraction after myocardial infarction (MI). Current guidelines recommend re-evaluation of cardioverter-defibrillator implantation 40 days post-MI, earliest. Medical therapy alone does not provide sufficient protection against SCD, especially in the first month post-MI, and needs time. Consequently, there is a gap in care of high-risk patients upon hospital discharge. The wearable cardioverter defibrillator (WCD) is a proven safe, effective therapy, which temporarily protects from SCD. Little information on WCD cost-effectiveness exists. We conducted this research to demonstrate the medical need of the device in the post-MI setting defining WCD cost-effectiveness.

METHODS & RESULTS

Based on a randomized clinical trials (RCTs) and Italian and international data, we developed a Markov-model comparing costs, patient survival, and quality-of-life, and calculated the Incremental Cost-Effectiveness Ratio (ICER) of a WCD vs. current standard of care in post-MI patients. The rather conservative base case analysis - based on the RCT intention-to-treat results - produced an ICER of €47,709 per Quality Adjusted Life Year (QALY) gained, which is far lower than the accepted threshold of €60,000 in the Italian National HS. The ICER per Life Year (LY) gained was €38,276.

CONCLUSION

WCD utilization in post-MI patients is clinically beneficial and cost-effective. While improving guideline directed patient care, the WCD can also contribute to a more efficient use of resources in the Italian HS, and potentially other HSs as well.

Real life experience with the wearable cardioverter-defibrillator in an international multicenter Registry

Patients at high risk for sudden cardiac death (SCD) may benefit from wearable cardioverter defibrillators (WCD) by avoiding immediate implantable cardioverter defibrillator (ICD) implantation. Different factors play an important role including patient selection, compliance and optimal drug treatment. We aimed to present real world data from 4 centers from Germany and Switzerland. Between 04/2012 and 03/2019, 708 patients were included in this registry. Patients were followed up over a mean time of 28 ± 35.5 months. Outcome data including gender differences and different etiologies of cardiomyopathy were analyzed. Out of 708 patients (81.8% males, mean age 61.0 ± 14.6), 44.6% of patients had non-ischemic cardiomyopathy, 39.8% ischemic cardiomyopathy, 7.9% myocarditis, 5.4% prior need for ICD explantation and 2.1% channelopathy. The mean wear time of WCD was 21.2 ± 4.3 h per day. In 46% of patients, left ventricular ejection fraction (LVEF) was > 35% during follow-up. The younger the patient was, the higher the LVEF and the lower the wear hours per day were. The total shock rate during follow-up was 2.7%. Whereas an appropriate WCD shock was documented in 16 patients (2.2%), 3 patients received an inappropriate ICD shock (0.5%). During follow-up, implantation of a cardiac implantable electronic device was carried out in 34.5% of patients. When comparing German patients (n = 516) to Swiss patients (n = 192), Swiss patients presented with longer wear days (70.72 ± 49.47 days versus 58.06 ± 40.45 days; p = 0.001) and a higher ICD implantation rate compared to German patients (48.4% versus 29.3%; p = 0.001), although LVEF at follow-up was similar between both groups. Young age is a negative independent predictor for the compliance in this large registry. The most common indication for WCD was non-ischemic cardiomyopathy followed by ischemic cardiomyopathy. The compliance rate was generally high with a decrease of wear hours per day at younger age. Slight differences were found between Swiss and German patients, which might be related to differences in mentality for ICD implantation.

A Wearable Cardioverter Defibrillator with a Low False Alarm Rate

BACKGROUND

A wearable cardioverter defibrillator (WCD) is indicated in appropriate patients to reduce risk for sudden cardiac death. Challenges for patients wearing a WCD have been frequent false shock alarms primarily due to ECG noise and wear discomfort.

OBJECTIVE

To test a contemporary WCD designed for reduced false shock alarms and improved comfort.

METHODS

130 patients with LVEF ≤ 40% and an active implantable cardioverter defibrillator (ICD) were fitted with the ASSURE WCD (Kestra Medical Technologies) and followed 30 days. WCD detection was enabled and shock alarm markers recorded, but shocks and shock alarms disabled. All WCD episodes and ICD VT/VF episodes were adjudicated. The primary endpoint was the false positive shock alarm rate with a performance goal of 1 every 3.4 days (0.29 per patient-day).

RESULTS

Of 163 WCD episodes, 4 were VT/VF and 159 non-VT/VF (121 rhythms with noise, 32 uncertain with noise, 6 atrial flutter without noise). Only 3 false positive shock alarm markers were recorded; 1 false positive shock alarm every 1,333 patient-days (0.00075 per patient-day, 95% CI: 0.00015-0.00361; p < 0.001). No ICD recorded VT/VF episodes meeting WCD detection criteria (≥ 170 bpm for ≥ 20 seconds) were missed by the WCD during 3,501 patient-days of use. Median wear was 31.0 days (IQR 2.0) and median daily use 23.0 hours (IQR 1.7). Adverse events were mostly mild: skin irritation (19.4%) and musculoskeletal discomfort (8.5%).

CONCLUSION

The ASSURE WCD demonstrated a low false positive shock alarm rate, low patient-reported discomfort, and no serious adverse events. This article is protected by copyright. All rights reserved.

OUP accepted manuscript

More than 40 years after the first implantable cardioverter-defibrillator (ICD) implantation, sudden cardiac death (SCD) still accounts for more than five million deaths worldwide every year. Huge efforts in the field notwithstanding, it is now increasingly evident that the current strategy of long-term prevention based on left ventricular ejection fraction as the key selection criterion is actually of very limited impact, also because the largest absolute numbers of SCD are encountered in the general population not known to be at risk. It has been recently reemphasized that SCD is often not so sudden, with almost half of the victims experiencing typical warning symptoms preceding the event. Importantly, heeded and prompt medical attention can dramatically improve survival. Essentially, such timely action increases the chances of the SCD event being witnessed by emergency medical services and provides the opportunity for early intervention. In addition, newer technologies incorporating digital data acquisition, transfer between interconnected devices, and artificial intelligence, should allow dynamic, real-time monitoring of diverse parameters and therefore better identification of subjects at short-term SCD risk. Along with warning symptoms, these developments allow a new approach of near-term prevention based on the hours and minutes preceding SCD. In the present review, we challenge the current paradigm of mid- and long-term prevention using ICD in patients at the highest risk of SCD, and introduce a complementary concept applicable to the entire population that would aim to pre-empt SCD by timely detection and intervention within the minutes or hours prior to the event.

When is a wearable defibrillator indicated?

INTRODUCTION

Wearable cardioverter-defibrillator (WCD) is a novel tool that may be of interest in situations with atransient risk of sudden cardiac death. It offers a temporary and easy to remove protection against malignant ventricular arrhythmias. In this review, the authors describe evidence in literature and different international guidelines and consensus.

AREAS COVERED

The authors searched PubMed, Cochrane Central Register of controlled trials, and Google Scholar for relevant studies and comments.

EXPERT OPINION

If a WCD is indicated, the observance must be as perfect as possible. Thus, patients need proper education in wearing the WCD.The temporary use of a WCD is reasonable in patients with a high risk for SCD, even with a low level of evidence with only one randomized clinical trial (VEST), as its disadvantages are limited to a transitory impairment in quality of life and a low risk of inappropriate shock.Indications are now well accepted: ischemic cardiomyopathy with LVEF below 35% before reassessment, recent onset of NICM or presumed myocarditis with LVEF ≤35% before reassessment, after ICD explant until reimplantation (e.g. infection), and bridge to transplant.Future guidelines on WCD in the prevention of SCD may be warranted to harmonize clinical practice especially in debated indications..

Wearable Cardioverter-Defibrillator Used as a Telemonitoring System in a Real-Life Heart Failure Unit Setting

BACKGROUND

In patients with reduced left ventricular ejection fraction (LVEF) who are at risk of sudden cardiac death, a wearable cardioverter-defibrillator (WCD) is recommended as a bridge to the recovery of LVEF or as a bridge to the implantation of a device. In addition to its function to detect and treat malignant arrhythmia, WCD can be used via an online platform as a telemonitoring system to supervise patients' physical activity, compliance, and heart rate.

METHODS

We retrospectively analyzed 173 patients with regard to compliance and heart rate after discharge.

RESULTS

Mean WCD wearing time was 59.75 ± 35.6 days; the daily wearing time was 21.19 ± 4.65 h. We found significant differences concerning the patients' compliance. Men showed less compliance than women, and younger patients showed less compliance than patients who were older. Furthermore, we analyzed the heart rate from discharge until the end of WCD prescription and found a significant decrease from discharge to 4, 8, or 12 weeks.

CONCLUSION

WCD can be used as a telemonitoring system to help the involved heart failure unit or physicians attend to and adjust the medical therapy. Furthermore, specific patient groups should be educated more intensively with respect to compliance.

Real-world experience with the wearable cardioverter defibrillator: clinical effectiveness and wear-time adherence in patients at high risk for sudden cardiac death

BACKGROUND

Previous studies established a role for the wearable cardioverter defibrillator (WCD) to effectively and safely bridge temporary risk for sudden cardiac death (SCD) in patients with advanced heart failure. The prognostic relevance of the WCD remains controversial.

OBJECTIVES

The authors investigated adherence to, as well as the safety and effectiveness of, WCD use in a real-world cohort of patients at high risk for SCD.

MATERIAL AND METHODS

All consecutive patients (n = 83) receiving a WCD at a German tertiary care hospital between April 2012 and December 2019 were retrospectively included in this analysis. Patient characteristics were collected at the time of the index hospitalization. Using the Zoll® lifeVest® (ZOLL Medical Corporation, Chelmsford, MA, USA) network database, two separate investigators evaluated adherence to the WCD as well as arrhythmic events during WCD wear time.

RESULTS

During 3680 wearing days (mean WCD wear time, 44 days) with a median daily wear time of 23.1 h, three arrhythmic events of relevance (sustained ventricular tachycardia, VT) occurred, one of which was sufficiently terminated by WCD shock. Another patient died from sudden cardiac death while pausing his WCD. Right bundle branch block correlated significantly with sustained VT occurrence (r = 0.3315; 95% CI -0.1265 to 0.3014; p = 0.0022). In 30 patients (36.1%) a cardioverter/defibrillator was implanted.

CONCLUSION

In a real-life clinical setting, the use of WCD in patients at high risk for sudden cardiac death is effective and safe and adherence to the device is high. The event rate for VA was lower than in comparable patient cohorts. Adherence remains a crucial issue as one patient in the present series died while not wearing the device.

Post-discharge arrhythmic risk stratification of patients with acute myocarditis and life-threatening ventricular tachyarrhythmias

AIMS

The outcomes of patients presenting with acute myocarditis and life-threatening ventricular arrhythmias (LT-VA) are unclear. The aim of this study was to assess the incidence and predictors of recurrent major arrhythmic events (MAEs) after hospital discharge in this patient population.

METHODS AND RESULTS

We retrospectively analysed 156 patients (median age 44 years; 77% male) discharged with a diagnosis of acute myocarditis and LT-VA from 16 hospitals worldwide. Diagnosis of myocarditis was based on histology or the combination of increased markers of cardiac injury and cardiac magnetic resonance (CMR) Lake Louise criteria. MAEs were defined as the relapse, after discharge, of sudden cardiac death or successfully defibrillated ventricular fibrillation, or sustained ventricular tachycardia (sVT) requiring implantable cardioverter-defibrillator therapy or synchronized external cardioversion. Median follow-up was 23 months [first to third quartile (Q1-Q3) 7-60]. Fifty-eight (37.2%) patients experienced MAEs after discharge, at a median of 8 months (Q1-Q3 2.5-24.0 months; 60.3% of MAEs within the first year). At multivariable Cox analysis, variables independently associated with MAEs were presentation with sVT [hazard ratio (HR) 2.90, 95% confidence interval (CI) 1.38-6.11]; late gadolinium enhancement involving ≥2 myocardial segments (HR 4.51, 95% CI 2.39-8.53), and absence of positive short-tau inversion recovery (STIR) (HR 2.59, 95% CI 1.40-4.79) at first CMR.

CONCLUSIONS

Among patients discharged with a diagnosis of myocarditis and LT-VA, 37.2% had recurrences of MAEs during follow-up. Initial CMR pattern and sVT at presentation stratify the risk of arrhythmia recurrence.