The Wearable Cardioverter Defibrillator in Nonischemic Cardiomyopathy: A US National Database Analysis. Can J Cardiol. 2016;32:1247.e1-1247.e6. [PMID: 26975224 DOI: 10.1016/j.cjca.2015.12.035]

Predictors of ventricular tachyarrhythmia in patients with a wearable cardioverter defibrillator: an international multicenter registry

BACKGROUND AND AIMS

Wearable cardioverter defibrillator (WCD) can protect patients from sudden cardiac death due to ventricular tachyarrhythmias and serve as a bridge to decision of definite defibrillator implantation. The aim of this analysis from an international, multicenter WCD registry was to identify predictors of sustained ventricular tachycardia (VT) and/or ventricular fibrillation (VF) in this population.

METHODS

One thousand six hundred seventy-five patients with WCD were included in a multicenter registry from 9 European centers, with a median follow-up of 440 days (IQR 120-893). The primary study end point was the occurrence of sustained VT/VF.

RESULTS

Sustained VT was detected by WCD in 5.4% and VF in 0.9% of all patients. Of the 30.3% of patients receiving ICD implantation during follow-up, sustained VT was recorded in 9.3% and VF in 2.6%. Non-ischemic cardiomyopathy (HR 0.5, p < 0.001), and medication with angiotensin-converting enzyme inhibitors (HR 0.7, p = 0.027) and aldosterone antagonists (HR 0.7, p = 0.005) were associated with a significantly lower risk of VT/VF.

CONCLUSIONS

Patients who received WCD due to a transient increased risk of sudden cardiac death have a comparatively lower risk of VT/VF in the presence of non-ischemic cardiomyopathy. Of note, optimal medical treatment for heart failure not only results in an improvement in left ventricular ejection fraction but also in a reduction in the risk for VT/VF.

Feasibility and First Results of Heart Failure Monitoring Using the Wearable Cardioverter-Defibrillator in Newly Diagnosed Heart Failure with Reduced Ejection Fraction

The wearable cardioverter–defibrillator (WCD) is used in patients with newly diagnosed heart failure and reduced ejection fraction (HFrEF). In addition to arrhythmic events, the WCD provides near-continuous telemetric heart failure monitoring. The purpose of this study was to evaluate the clinical relevance of additionally recorded parameters, such as heart rate or step count. We included patients with newly diagnosed HFrEF prescribed with a WCD. Via the WCD, step count and heart rate were acquired, and an approximate for heart rate variability (HRV5) was calculated. Multivariate analysis was performed to analyze predictors for an improvement in left ventricular ejection fraction (LVEF). Two hundred and seventy-six patients (31.9% female) were included. Mean LVEF was 25.3 ± 8.5%. Between the first and last seven days of usage, median heart rate fell significantly (p < 0.001), while median step count and HRV5 significantly increased (p < 0.001). In a multivariate analysis, a delta of HRV5 > 23 ms was an independent predictor for LVEF improvement of ≥10% between prescription and 3-month follow-up. Patients with newly diagnosed HFrEF showed significant changes in heart rate, step count, and HRV5 between the beginning and end of WCD prescription time. HRV5 was an independent predictor for LVEF improvement and could serve as an early indicator of treatment response.

Management of nonischemic-dilated cardiomyopathies in clinical practice: a position paper of the working group on myocardial and pericardial diseases of Italian Society of Cardiology

: Nonischemic-dilated cardiomyopathy (NIDCM) is an entity that gathers extremely heterogeneous diseases. This awareness, although leading to continuous improvement in survival, has increased the complexity of NIDCM patients' management. Even though the endorsed 'red-flags' approach helps clinicians in pursuing an accurate etiological definition in clinical practice, it is not clear when and how peripheral centers should interact with referral centers with specific expertise in challenging scenarios (e.g. postmyocarditis and genetically determined dilated cardiomyopathy) and with easier access to second-line diagnostic tools and therapies. This position paper will summarize each step in NIDCM management, highlighting the multiple interactions between peripheral and referral centers, from first-line diagnostic workup and therapy to advanced heart failure management and long-term follow-up.

Effectiveness, efficacy, and safety of wearable cardioverter-defibrillators in the treatment of sudden cardiac arrest - Results from a health technology assessment

OBJECTIVES

To assess the effectiveness, efficacy, and safety of a wearable cardioverter-defibrillator (WCD) in adult persons with high risk for sudden cardiac arrest and for which an implantable cardioverter is currently not applicable.

METHODS

We performed a systematic literature search in Medline, Embase, Cochrane Library, and CRD-databases. Study selection was performed by two reviewers independently. Data were presented quantitatively; due to heterogeneity of studies no meta-analysis was performed.

RESULTS

One randomized-controlled trial (RCT), one non-randomized comparative trial, and forty-four non-comparative trials were included. The RCT reported an overall mortality of 3.1 percent in the WCD group versus 4.9 percent in controls (relative risk [RR]: .64; 95 percent confidence interval [CI], .43-.98, p = .04), but no significant effect on arrhythmia-related mortality. The RR for arrhythmia-related mortality amounted to .67 (95 percent CI, .37-1.21, p = .18) as assessed in the RCT. Appropriate shocks were observed in 1.3 percent of patients in both comparative studies, and inappropriate shocks in .6 percent of patients in the RCT. Termination of ventricular tachycardia (VT) or ventricular fibrillation (VF) was successful in 75 to 100 percent of appropriate shocks in all studies. Adverse events assessed in the RCT showed a lower incidence of shortness of breath (38.8 percent vs. 45.3 percent; p = .004), higher incidence of rash at any location (15.3 percent vs. 7.1 percent; p < .001), and higher incidence of itching at any location (17.2 percent vs. 6.4 percent; p < .001) for WCD.

CONCLUSIONS

Available evidence demonstrates that the WCD detects and terminates VT/VF events reliably and shows a high rate of appropriate shocks in mixed patient populations. Data of large registries confirm that the WCD is a safe intervention.

Extended use of the wearable cardioverter-defibrillator in patients at risk for sudden cardiac death

Aims

Data on outcomes in patients using the wearable cardioverter-defibrillator (WCD) > 90 days are limited. We aimed to analyse the clinical course of patients with WCD use ≤90 days vs. WCD use >90 days.

Methods and results

We assessed arrhythmia events during WCD use, and ejection fraction (EF) improvement/implantable cardioverter-defibrillator (ICD) implantation at the end of WCD use in patients with WCD use ≤90 days vs. WCD use >90 days enrolled in the WEARIT-II registry, further assessed by disease aetiology (ischaemic vs. non-ischaemic vs. congenital/inherited heart disease). There were 981 (49%) patients with WCD use >90 days, and 1019 patients with WCD use ≤90 days (median 120 vs. 55 days). There was a lower incidence of sustained ventricular tachycardia/ventricular fibrillation (VT/VF) events (11 vs. 50 events per 100 patient-years, P < 0.001), WCD treated VT/VF events (1 vs. 8 events per 100 patient-years, P < 0.001), and non-sustained VT events (21 vs. 51 events per 100 patient-years, P = 0.008) with WCD use >90 vs. WCD use ≤90 days. Non-ischaemic cardiomyopathy patients presented with similar rates of sustained VT/VF events during WCD use >90 vs. ≤90 days (13.4 vs. 13.7 events per 100 patient-years, P = 0.314), while most of these events terminated spontaneously. One-third of the patients with extended WCD use further improved their EF and they were not implanted with an ICD, with similar rates among ischaemic and non-ischaemic patients.

Conclusions

In WEARIT-II, patients with extended WCD use >90 days remain at risk for ventricular arrhythmia events. One-third of the patients with WCD use >90 days further improved their EF, avoiding the need to consider ICD implantation.

Wearable Cardioverter-Defibrillator Therapy for the Prevention of Sudden Cardiac Death: A Systematic Review and Meta-Analysis

OBJECTIVES

This study sought to synthesize the available evidence on the use of the wearable cardioverter-defibrillator (WCD).

BACKGROUND

Observational WCD studies for the prevention of sudden cardiac death have provided conflicting data. The VEST (Vest Prevention of Early Sudden Death) trial was the first randomized controlled trial (RCT) showing no reduction in sudden cardiac death as compared to medical therapy only.

METHODS

We searched PubMed, EMBASE, and Google Scholar for studies reporting on the outcomes of patients wearing WCDs from January 1, 2001, through March 20, 2018. Rates of appropriate and inappropriate WCD therapies were pooled. Estimates were derived using DerSimonian and Laird's method.

RESULTS

Twenty-eight studies were included (N = 33,242; 27 observational, 1 RCT-WCD arm). The incidence of appropriate WCD therapy was 5 per 100 persons over 3 months (95% confidence interval [CI]: 3.0 to 6.0, I2 = 93%). In studies on ischemic cardiomyopathy, the appropriate WCD therapy incidence was lower in the VEST trial (1 per 100 persons over 3 months; 95% CI: 1.0 to 2.0) as compared with observational studies (11 per 100 persons over 3 months; 95% CI: 11.0 to 20.0; I2 = 93%). The incidence of inappropriate therapy was 2 per 100 persons over 3 months (95% CI: 1.0 to 3.0; I2 = 93%). Mortality while wearing WCD was rare at 0.7 per 100 persons over 3 months (95% CI: 0.3 to 1.7; I2 = 94%).

CONCLUSIONS

The rate of appropriately treated WCD patients over 3 months of follow-up was substantial; higher in-observational studies as compared with the VEST trial. There was significant heterogeneity. More RCTs are needed to justify continued use of WCD in primary prevention.

Role of the Wearable Defibrillator in Newly Diagnosed Heart Failure

PURPOSE OF REVIEW

The wearable defibrillator (WCD) was shown to be safe and effective in detecting and terminating ventricular tachyarrhythmias and therefore allows temporary protection from sudden cardiac death. This review gives an overview of the current data on WCD in newly diagnosed cardiomyopathy.

RECENT FINDINGS

Patients with newly diagnosed heart failure and reduced LVEF appear to have an increased risk of ventricular tachyarrhythmias, which may decrease over time when heart failure medication is optimized and left ventricular function improves. This was shown to apply for patients with ischemic and non-ischemic cardiomyopathy, including peripartum cardiomyopathy. Prolongation of the WCD period may support to further optimization of heart failure medication, by protecting the patient from sudden cardiac death during this time and to avoid untimely ICD implantation. The WCD should be considered in structured patient management for newly diagnosed heart failure during the early phase of the disease. Careful patient selection, structured patient management, and patient's compliance is crucial for a successful WCD strategy.

[Wearable defibrillator : Current evidence]

The wearable cardioverter/defibrillator (WCD) is safe and effective in the prevention of sudden cardiac death, and has found its way into international guidelines and clinical practice. Nearly 40,000 patients with a WCD have been published in clinical registries and one randomized study has recently been presented. Especially patients with newly diagnosed cardiomyopathy with severely reduced left ventricular function show an increased risk for ventricular tachyarrhythmias and may benefit from a WCD. In these patients without an indication for an implantable cardioverter-defibrillator (ICD), the WCD offers protection from sudden cardiac death during initiation and optimization of heart failure medication. Critical patient selection and structured patient management is crucial for successful WCD prescription. This review gives an overview of the current data and recommendations on WCD.

Misunderstood or Mistrusted? The Under-Utilization of the Wearable Cardioverter Defibrillator in Clinical Practice

Annually in the United States, sudden cardiac death (including out-of-hospital cardiac arrests) is responsible for over 300,000 deaths, comprising 40%-50% of total mortality rates from cardiovascular disease. Among the highest-risk patients are those with ischemic and nonischemic cardiomyopathy who have a reduced left ventricular ejection fraction (≤ 35%-40%). However, not everyone is a candidate for an implantable cardioverter defibrillator. In 2002, the wearable cardioverter defibrillator (WCD) gained Food and Drug Administration approval for its efficacy in the prevention of sudden cardiac arrest or death in certain at-risk populations and has been making its way into national guidelines with Class IIa to IIb strength of evidence. Despite the prevalence of sudden cardiac death and the demonstrated efficacy of the WCD, this technology remains under-prescribed. This study seeks to explicate the potential causes for under-utilization of WCDs and offer means of overcoming barriers to its use. Among these reasons include confusion about the guidelines and when to prescribe, who can prescribe the device, and debate about whether the WCD is efficacious based on recent studies. Other social barriers to prescription include cost and adherence to therapy by the patient. This study sets the stage for further research on the improvement of education about the device and opens discourse about its prescription in clinical practice.

Indications for and outcome in patients with the wearable cardioverter-defibrillator in a nurse-based training programme: results of the Austrian WCD Registry

BACKGROUND

The wearable cardioverter-defibrillator is a treatment option for patients at temporarily high risk of sudden cardiac death or in whom implantation of a cardioverter-defibrillator is temporarily not possible.

OBJECTIVES

The aim of this study was to provide real-world data on patients receiving this therapy in a nurse-based wearable cardioverter-defibrillator training programme.

METHODS

A registry including all patients prescribed with a wearable cardioverter-defibrillator in Austria between 2010 and 2016. Overall, 448 patients received a wearable cardioverter-defibrillator in 48 centres. Patients received structured nurse-based wearable cardioverter-defibrillator educational initial training followed by remote monitoring.

RESULTS

Main indications were: severe non-ischaemic cardiomyopathy (21%); recent myocardial infarction and percutaneous coronary intervention (20%); and stable coronary artery disease with percutaneous coronary intervention/coronary artery bypass grafting (14%). Eleven patients (2.5%) received 22 appropriate wearable cardioverter-defibrillator shocks. Two patients (0.4%) received three inappropriate shocks. The risk of sudden cardiac death varied between different aetiologies. Eight out of 11 (73%) patients received their first wearable cardioverter-defibrillator shock within 30 days. The main reasons for termination of the wearable cardioverter-defibrillator therapy were implantable cardioverter-defibrillator implantation (55.5%) and improvement of left ventricular ejection fraction to more than 35% (33%).

CONCLUSION

The wearable cardioverter-defibrillator is an effective and safe treatment option in patients at either transiently elevated risk of ventricular tachycardia/ventricular fibrillation or mandated postponed implantable cardioverter-defibrillator implantation, with a 2.5% shock rate over a median 54 days wearable cardioverter-defibrillator treatment period. However, both the wearable cardioverter-defibrillator shock rate and implantable cardioverter-defibrillator implantation rate vary widely depending on the wearable cardioverter-defibrillator indication. Nurse-based wearable cardioverter-defibrillator training is associated with high patient adherence, with a median wearing duration per day of 23.5 (1-24) hours.

Impairment of Quality of Life among Patients with Wearable Cardioverter Defibrillator Therapy (LifeVest®): A Preliminary Study

Background

Wearable cardioverter defibrillator (WCD) therapy is feasible and safe in patients as a transient protection against sudden cardiac death (SCD). However, the impact of WCD therapy on quality of life (QoL) has not been studied.

Methods

In our single-centre study, 109 consecutive patients with a prescription of WCD were retrospectively analysed. Quality of life has been assessed by a standardized questionnaire (EQ-5D-3L, modified). Additionally, clinical baseline and follow-up data and recorded arrhythmic episodes were evaluated.

Results

Mean WCD therapy time was 56.2 (± 42.4) days, with a daily wear time of 19.7 (± 5) hours. A total of 3441 arrhythmia episodes were detected. Of these, 27 (1%) were adequate but did not require shock therapy. Likewise, no inadequate shock therapy occurred. WCD therapy negatively affected quality of life: 43% of patients reported mental health issues. 37% reported pain or discomfort. Self-care, usual activities, and mobility were restricted in 17%, 48%, and 36%, respectively. 29% were afraid of receiving shock therapy, and 48% suffered from sleep disturbance. However, 64% indicated having felt safe during WCD therapy. Accordingly, average quality of life was rated 70/100 points.

Conclusion

In our cohort, no SCD was prevented by WCD therapy. In contrast, in this preliminary study quality of life was reduced. Thus, careful recommendation of WCD therapy for high risk patients should be considered.

Outcomes after asystole events occurring during wearable defibrillator-cardioverter use

AIM

To examine whether wearable cardioverter defibrillator (WCD) alarms for asystole improve patient outcomes and survival.

METHODS

All asystole episodes recorded by the WCD in 2013 were retrospectively analyzed from a database of device and medical record documentation and customer call reports. Events were classified as asystole episodes if initial presenting arrhythmia was asystole (< 10 beats/minor ≥ 5 s pause). Survival was defined as recovery at the scene or arrival to a medical facility alive, or not requiring immediate medical attention. Episodes occurring in hospitals, nursing homes, or ambulances were considered to be under medical care. Serious asystole episodes were defined as resulting in unconsciousness, hospital transfer, or death.

RESULTS

Of the total 51933 patients having worn the WCD in 2013, there were 257 patients (0.5%) who had asystole episodes and comprised the study cohort. Among the 257 patients (74% male, median age 69 years), there were 264 asystole episodes. Overall patient survival was 42%. Most asystoles were considered “serious” (n = 201 in 201 patients, 76%), with a 26% survival rate. All 56 patients with “non-serious” asystole episodes survived. Being under medical care was associated with worse survival of serious asystoles. Among acute survivors, 20% later died during WCD use (a median 4 days post asystole episode). Of the 86 living patients at the end of WCD use period, 48 (56%) received ICD/pacemaker and 17 (20%) improved their condition.

CONCLUSION

Survival rates after asystole in patients with WCD are higher than historically reported survival rates. Those under medical care at time of asystole exhibited lower survival.

Therapy optimization in patients with heart failure: the role of the wearable cardioverter-defibrillator in a real-world setting

Background

The wearable cardioverter-defibrillator (WCD) has emerged as a valuable tool to temporarily protect patients at risk for sudden cardiac death (SCD). The aim of this study was to determine the value of the WCD for therapy optimization of heart failure patients.

Methods

One hundred five consecutive patients that received WCD between 4/2012 and 9/2016 were included in the study. All patients were followed for clinical outcome and echocardiographic parameters during WCD therapy and had continued follow-up after WCD therapy, irrespective of subsequent implantable cardioverter-defibrillator (ICD) implantation.

Results

The most common indication for WCD were newly diagnosed ischemic (ICM) or non-ischemic cardiomyopathy (NICM) with left ventricular ejection fraction (LVEF) ≤35%. Mean WCD wear time was 68.8 ± 50.4 days with a mean daily use of 21.5 ± 3.5 h. Five patients (4.8%) received a total of five appropriate WCD shocks.

During WCD wear, patients with ICM and NICM showed significant improvement in LVEF, reducing the proportion of patients with a need for primary preventive ICD implantation to 54.8% (ICM) and 48.8% (NICM). An ICD was finally implanted in 51.4% of the study patients (24 trans-venous ICDs, 30 subcutaneous ICDs).

After discontinuation of WCD therapy, all patients were followed for a mean of 18.6 ± 12.3 months. 5.6% of patients with implanted ICDs received appropriate therapies. No patient with subcutaneous ICD needed change to a trans-venous device. None of the patients without an implanted ICD suffered from ventricular tachyarrhythmias and no patient died suddenly.

In patients with NICM a significant LVEF improvement was observed during long-term follow-up (from 34.8 ± 11.1% to 41.0 ± 10.2%).

Conclusions

WCD therapy successfully bridged all patients to either LVEF recovery or ICD implantation. Following WCD, ICD implantation could be avoided in almost half of the patients. In selected patients, prolongation of WCD therapy beyond 3 months might further prevent unnecessary ICD implantation. The WCD as an external monitoring system contributed important information to optimize device selection in patients that needed ICD implantation.

Wearable cardioverter defibrillator: Bridge or alternative to implantation?

The implantable cardioverter-defibrillator (ICD) is effective to prevent sudden cardiac death (SCD) in selected patients with heart disease known to be at high risk for ventricular arrhythmia. Nevertheless, this invasive and definitive therapy is not indicated in patients with potentially transient or reversible causes of sudden death, or in patients with temporary contra-indication for ICD placement. The wearable cardioverter defibrillator (WCD) is increasingly used for SCD prevention both in patients awaiting ICD implantation or with an estimated high risk of ventricular arrhythmia though to be transient. We conducted a review of current clinical uses and benefits of the WCD, and described its technical aspects, limitations and perspectives.

A real world wearable cardioverter defibrillator experience - Very high appropriate shock rate in ischemic cardiomyopathy patients at a European single-center

BACKGROUND

The wearable cardioverter defibrillator (WCD) has emerged as a valuable tool to protect patients with increased risk of sudden cardiac death (SCD). We sought to characterize WCD patients and to analyze predictors of ventricular arrhythmia (VA) occurrence and WCD shock delivery.

METHODS AND RESULTS

One hundred fourteen patients with WCD use were included in the study. Indications were mainly ischemic cardiomyopathy (ICM; 31.6%), non-ICM (45.6%) and explantation of implantable cardioverter defibrillator due to device infection (11.4%). We observed sustained VA in 9.6% of the study population and 6.1% received an appropriate shock. VA occurred in 16.7% of ICM, 3.8% of non-ICM and 15.4% of patients with device infection.

CONCLUSIONS

Our data demonstrate a very high rate of sustained VA in patients at risk for SCD during WCD use. ICM patients, including those with recent MI, bore the highest risk.

Ventricular arrhythmias in patients with newly diagnosed nonischemic cardiomyopathy: Insights from the PROLONG study

BACKGROUND

Patients with nonischemic cardiomyopathy (NICM) reportedly have low incidence of appropriate shocks from wearable cardioverter-defibrillators (WCDs). A recent study questions the benefit from primary preventive implantation of implantable cardioverter-defibrillators in NICM. We therefore analyzed a subgroup of patients with NICM from the PROLONG study.

HYPOTHESIS

Patients with newly diagnosed NICM show a risk for ventricular tachyarrhythmia.

METHODS

The PROLONG study included 167 patients with newly diagnosed heart failure and left ventricular ejection fraction (LVEF) ≤35% with a WCD. Patients with NICM were identified and included in this analysis.

RESULTS

117 patients presented with NICM. Sixty-five (55%) were male; mean age was 51 ± 15 years. Mean LVEF at diagnosis was 23% ± 7%. Mean follow-up was 11 ± 10 months. Mean WCD wear time was 101 ± 82 days; mean wear time per day was 21.4 ± 4.5 hours. Overall, 12 ventricular arrhythmias occurred in 10 (9%) patients (6 DCM, 4 PPCM). Nine appropriate WCD shocks for hemodynamically unstable ventricular tachycardia/fibrillation in 8 (7%) patients were observed. Two patients presented sustained hemodynamically stable ventricular tachycardia for >30 minutes detected by the WCD, but withheld WCD therapy.

CONCLUSIONS

Patients with newly diagnosed NICM and LVEF ≤35% show an elevated risk of ventricular tachycardia/fibrillation during initiation and optimization of heart failure therapy. To prevent sudden cardiac death, WCD should be considered in patients with newly diagnosed NICM with severely reduced LVEF.