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.

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.

The Heart Failure Optimization Study (HF-OPT): rationale and design

BACKGROUND

According to the current guidelines, implantable cardioverter-defibrillators (ICD) for primary prevention in patients with heart failure and reduced ejection fraction (HFrEF) should not be considered until optimal guideline-directed medical therapy (GDMT) has been achieved for a minimum of 3 months. Optimization of GDMT often needs time beyond 3 months after diagnosis. The aim of the Heart Failure Optimization Study (HF-OPT) is to evaluate the recovery of left ventricular function beyond 3 months after diagnosis of newly diagnosed HFrEF.

METHODS

The HF-OPT multicenter study is comprised of two non-randomized phases (registry and study). During the first 90 days a wearable cardioverter-defibrillator (WCD) is prescribed and patients are enrolled in an observational pre-study registry. Registry subjects meeting inclusion criteria for the study portion at day 90 have ongoing left ventricular ejection fraction (LVEF) reassessment at 90, 180 and 360 days after the index hospital discharge, regardless of continued WCD use. Approximately 600 subjects will be enrolled in the study portion. Of those, one-third are anticipated to start the study phase at day 90 with reduced LVEF. The primary objective of this study is to observe the rate of recovery of LVEF > 35% between 90 and 180 days, while key secondary endpoints include mortality and WCD recorded arrhythmias and shocks.

DISCUSSION

The HF-OPT study will provide important information on the rate of additional recovery of LVEF > 35%, between 90 and 180 days, in newly diagnosed HF with reduced LVEF patients being titrated with GDMT. The results of the study may impact indications for primary prophylactic ICD implantation.

Sudden cardiac death while waiting: do we need the wearable cardioverter-defibrillator?

Sudden cardiac death (SCD) is the most frequent cause of cardiovascular death in industrialized nations. Patients with cardiomyopathy are at increased risk for SCD and may benefit from an implantable cardioverter-defibrillator (ICD). The risk of SCD is highest in the first months after myocardial infarction or first diagnosis of severe non-ischemic cardiomyopathy. On the other hand, left ventricular function may improve in a subset of patients to such an extent that an ICD might no longer be needed. To offer protection from a transient risk of SCD, the wearable cardioverter-defibrillator (WCD) is available. Results of the first randomized clinical trial investigating the role of the WCD after myocardial infarction were recently published. This review is intended to provide insight into data from the VEST trial, and to put these into perspective with studies and clinical experience. As a non-invasive, temporary therapy, the WCD may offer advantages over early ICD implantation. However, recent data demonstrate that patient compliance and education play a crucial role in this new concept of preventing SCD.

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.

Extended follow-up after wearable cardioverter-defibrillator period: the PROLONG-II study

AIM

The wearable cardioverter-defibrillator (WCD) is used for temporary protection from sudden cardiac death (SCD) in patients with newly diagnosed heart failure with reduced ejection fraction before considering an implantable cardioverter-defibrillator (ICD). However, the prognostic significance of the WCD remains controversial due to conflicting evidence. The aim of the present study was to evaluate prognosis of patients receiving life-saving WCD shocks.

METHODS AND RESULTS

All patients receiving a WCD at Hannover Medical School for heart failure with reduced ejection fraction between 2012 and 2017 were included. Data were acquired at baseline, at 3 months and at last available follow-up (FU). Three hundred and fifty-three patients were included (69% male; age 56 ± 15 years; left ventricular ejection fraction 25 ± 8%). FU after the WCD was 2.8 ± 1.5 years with a maximum of 6.8 years. Daily WCD wear time was 22 ± 4 h. Fourteen patients (4%) received appropriate WCD shocks. Two patients (0.6%) died during the WCD period. Thirty patients (9%) died during extended FU. Mean estimated survival after the WCD was similar between patients with and without WCD shocks. Patients without an ICD recommendation after WCD prescription did not experience SCD during FU.

CONCLUSIONS

Patients with WCD shocks showed a favourable survival. Patients without an ICD recommendation after WCD prescription had no SCD during FU. These findings support the practice of careful risk stratification before considering an ICD and the use of the WCD for temporary protection from SCD.

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

Aims 

We aimed to provide contemporary real-world data on wearable cardioverter-defibrillator (WCD) use, not only in terms of effectiveness and safety but also compliance and acceptability.

Methods and results 

Across 88 French centres, the WEARIT-France study enrolled retrospectively patients who used the WCD between May 2014 and December 2016, and prospectively all patients equipped for WCD therapy between January 2017 and March 2018. All patients received systematic education session through a standardized programme across France at the time of initiation of WCD therapy and were systematically enrolled in the LifeVest Network remote services. Overall, 1157 patients were included (mean age 60 ± 12 years, 16% women; 46% prospectively): 82.1% with ischaemic cardiomyopathy, 10.3% after implantable cardioverter-defibrillator explant, and 7.6% before heart transplantation. Median WCD usage period was 62 (37–97) days. Median daily wear time of WCD was 23.4 (22.2–23.8) h. In multivariate analysis, younger age was associated with lower compliance [adjusted odds ratio (OR) 0.97, 95% confidence interval (CI) 0.95–0.99, P < 0.01]. A total of 18 participants (1.6%) received at least one appropriate shock, giving an incidence of appropriate therapy of 7.2 per 100 patient-years. Patient-response button allowed the shock to be aborted in 35.7% of well-tolerated sustained ventricular arrhythmias and in 95.4% of inappropriate ventricular arrhythmia detection, finally resulting in an inappropriate therapy in eight patients (0.7%).

Conclusion

Our real-life findings reinforce previous studies on the efficacy and safety of the WCD in the setting of transient high-risk group in selected patients. Moreover, they emphasize the fact that when prescribed appropriately, in concert with adequate patient education and dedicated follow-up using specific remote monitoring system, compliance with WCD is high and the device well-tolerated by the patient.

Wearable cardioverter-defibrillators after myocardial infarction: a review of its clinical utility and unmet needs in current clinical practice

Sudden cardiac death is one of the leading causes of death in the older population. Compared with the general population, patients who experienced a myocardial infarction are four to six times more likely to experience sudden cardiac death. Though primary percutaneous coronary intervention considerably reduces mortality in patients who experienced a myocardial infarction, a non-negligible number of sudden cardiac deaths still occurs. Despite the high incidence rate of sudden cardiac deaths during the first month after myocardial infarction, prophylactic use of implantable cardioverter-defibrillators has so far failed to convey a survival benefit. Therefore, current clinical guidelines recommend that cardioverter-defibrillator implantation is contraindicated until 90 days after myocardial infarction. Wearable cardioverter-defibrillators were first approved for clinical use in 2002 and are currently considered as a bridge to therapy in patients with myocardial infarction with a reduced left ventricular ejection fraction in whom cardioverter-defibrillator implantation is temporarily not indicated. However, there is insufficient recognition among interventional cardiologists of the use of wearable cardioverter-defibrillators for preventing sudden cardiac death after myocardial infarction. Hence, we reviewed the evidence of the efficacy of wearable cardioverter-defibrillators used in patients following myocardial infarction to achieve better management of sudden cardiac death.

Sex differences in arrhythmic burden with the wearable cardioverter-defibrillator

BACKGROUND

Data on the arrhythmic burden of women at risk for sudden cardiac death are limited, especially in patients using the wearable cardioverter-defibrillator (WCD).

OBJECTIVE

We aimed to characterize WCD compliance, atrial and ventricular arrhythmic burden, and WCD outcomes by sex in patients enrolled in the Prospective Registry of Patients Using the Wearable Cardioverter Defibrillator (WEARIT-II U.S. Registry).

METHODS

In the WEARIT-II Registry, we stratified 2000 patients by sex into women (n = 598) and men (n = 1402). WCD wear time, ventricular and atrial arrhythmic events during WCD use, and implantable cardioverter-defibrillator (ICD) implantation rates at the end of WCD use were evaluated.

RESULTS

The mean WCD wear time was similar in women and men (94 days vs 90 days; P = .145), with longer daily use in women (21.4 h/d vs 20.7 h/d; P = .001). Burden of ventricular tachycardia or ventricular fibrillation was higher in women, with 30 events per 100 patient-years compared with 18 events per 100 patient-years in men (P = .017), with similar findings for treated and non-treated ventricular tachycardia/ventricular fibrillation. Recurrent atrial arrhythmias/sustained ventricular tachycardia was also more frequent in women than in men (167 events per 100 patient-years vs 73 events per 100 patient-years; P = .042). However, ICD implantation rate at the end of WCD use was similar in both women and men (41% vs 39%; P = .448).

CONCLUSION

In the WEARIT-II Registry, we have shown a higher burden of ventricular and atrial arrhythmic events in women than in men. ICD implantation rates at the end of WCD use were similar. Our findings warrant monitoring women at risk for sudden cardiac death who have a high burden of atrial and ventricular arrhythmias while using the WCD.

The impact of wearable cardioverter-defibrillator use on long-term decision for implantation of a cardioverter-defibrillator in a semirural acute care hospital

Purpose

Large-scale multi-center studies have reported on efficacy of the wearable cardioverter-defibrillator (WCD). However, outcomes focused on WCD patients treated at community-based acute care centers are lacking.

Methods

Patients with cardiomyopathy were included when left ventricular ejection fraction (LVEF) at baseline was ≤ 35%. There were 120 patients meeting the criteria who also had LVEF measured at baseline and after 90 days of WCD use.

Results

After 90 days of WCD use, there were 44 (37%) patients in whom LVEF improved to > 35%. Comparison of patients, by whether LVEF improved or not, indicated that median days of WCD wear and hours of daily use were similar as well as characteristics, such as gender, age, and starting LVEF; and diagnoses leading to WCD prescription were similar between groups as were symptom-based prescription of medications. At the end of WCD use, improved LVEF > 35% correlated with fewer implantable cardioverter-defibrillator (ICD) implants. There were 4 (3%) episodes of new atrial fibrillation detected during WCD use. The WCD appropriately delivered a shock to 3 (2.5%) patients with VT/VF being terminated by the first shock. All shocked patients survived for at least 24 h post-shock.

Conclusions

During WCD use, ischemic and non-ischemic cardiomyopathy patients manifest improved LVEF by 90 days. Long-term care decisions, such as implantation of an ICD, were influenced by LVEF improvement and occurrence of spontaneous VT/VF. The WCD protected patients from sudden cardiac death (SCD) until patient response to guideline-directed medical therapy could be determined.

Influence of decompensated heart failure on cardiac acoustic biomarkers: impact on early readmissions

Aims

Preventing hospitalization by detecting early evidence of heart failure (HF) decompensation in an outpatient setting can improve patient's quality of life and reduce costs of care. The purpose of this study was to assess the value of cardiac acoustic biomarkers (CABs), a combination of cardiohaemic vibrations synchronized with ECG signals, and heart rate (HR) for detecting HF decompensation during first 3 months after hospital discharge for HF.

Methods and results

Patients with an ejection fraction ≤35% (HFrEF) and hospitalized for decompensated HF were enrolled in a prospective observational study. All subjects wore a wearable cardioverter‐defibrillator (ZOLL LifeVest^®, Pittsburgh, PA, USA) that is capable of recording CABs and HR. The primary endpoint of the study was the first HF event, defined as HF readmission or HF emergency room visit. From June 2017 through August 2019, 671 patients with HFrEF were enrolled. Eighty‐one patients (12.1%) had a total of 112 HF events. The algorithm detected HF events with a median of 32 days (interquartile range = 11‐45) in advance of the first HF event. The algorithm had a sensitivity of 69%, specificity of 60%, positive predictive value of 19%, and a negative predictive value of 94%. Of note, the baseline (first 7 days post‐enrolment) algorithm using CABs and HR was superior to New York Heart Association classification in detecting patients more likely to have HF decompensation (sensitivity and specificity of 61% and 68% vs. 46% and 55%, respectively).

Conclusions

This prospective international registry showed that an algorithm incorporating CABs and HR data detected HF events 30 days in advance of the event in patients with HFrEF during first 3 months after hospital discharge. Therefore, integrating CAB technology into clinical practice may prevent HF rehospitalizations.

Decline in physical activity in the weeks preceding sustained ventricular arrhythmia in women

Background

Heightened risk of cardiac arrest following physical exertion has been reported. Among patients with an implantable defibrillator, an appropriate shock for sustained ventricular arrhythmia was preceded by a retrospective self-report of engaging in mild-to-moderate physical activity. Previous studies evaluating the relationship between activity and sudden cardiac arrest lacked an objective measure of physical activity and women were often underrepresented.

Objective

To determine the relationship between physical activity, recorded by accelerometer in a wearable cardioverter-defibrillator (WCD), and sustained ventricular arrhythmia among female patients.

Methods

A dataset of female adult patients prescribed a WCD for a diagnosis of myocardial infarction or dilated cardiomyopathy was compiled from a commercial database. Curve estimation, to include linear and nonlinear interpolation, was applied to physical activity as a function of time (days before arrhythmia).

Results

Among women who received an appropriate WCD shock for sustained ventricular arrhythmia (N = 120), a quadratic relationship between time and activity was present prior to shock. Physical activity increased starting at the beginning of the 30-day period up until day -16 (16 days before the ventricular arrhythmia) when activity begins to decline.

Conclusion

For patients who received treatment for sustained ventricular arrhythmia, a decline in physical activity was found during the 2 weeks preceding the arrhythmic event. Device monitoring for a sustained decline in physical activity may be useful to identify patients at near-term risk of a cardiac arrest.

Protected risk stratification with the wearable cardioverter-defibrillator: results from the WEARIT-II-EUROPE registry

Background

The prospective WEARIT-II-EUROPE registry aimed to assess the value of the wearable cardioverter-defibrillator (WCD) prior to potential ICD implantation in patients with heart failure and reduced ejection fraction considered at risk of sudden arrhythmic death.

Methods and results

781 patients (77% men; mean age 59.3 ± 13.4 years) with heart failure and reduced left ventricular ejection fraction (LVEF) were consecutively enrolled. All patients received a WCD. Follow-up time for all patients was 12 months. Mean baseline LVEF was 26.9%. Mean WCD wearing time was 75 ± 47.7 days, mean daily WCD use 20.3 ± 4.6 h. WCD shocks terminated 13 VT/VF events in ten patients (1.3%). Two patients died during WCD prescription of non-arrhythmic cause. Mean LVEF increased from 26.9 to 36.3% at the end of WCD prescription (p < 0.01). After WCD use, ICDs were implanted in only 289 patients (37%). Forty patients (5.1%) died during follow-up. Five patients (1.7%) died with ICDs implanted, 33 patients (7%) had no ICD (no information on ICD in two patients). The majority of patients (75%) with the follow-up of 12 months after WCD prescription died from heart failure (15 patients) and non-cardiac death (15 patients). Only three patients (7%) died suddenly. In seven patients, the cause of death remained unknown.

Conclusions

Mortality after WCD prescription was mainly driven by heart failure and non-cardiovascular death. In patients with HFrEF and a potential risk of sudden arrhythmic death, WCD protected observation of LVEF progression and appraisal of competing risks of potential non-arrhythmic death may enable improved selection for beneficial ICD implantation.

Graphic abstract

Wearable cardioverter-defibrillators: A review of evidence and indications

The wearable cardioverter-defibrillator (WCD) was first approved for clinical use in 2002, and is routinely used in select populations at high risk for sudden cardiac death. WCDs are frequently considered as a bridge to definitive therapy or in circumstances where insertion of conventional implantable cardioverter-defibrillators (ICD) is temporarily contraindicated. In this review, we summarize the literature on WCDs. From prospective trials to the first randomized controlled trial with WCD, there is a growing body of evidence that suggests that the WCD is safe and effective. In the first randomized controlled trial of the WCD (VEST Trial), there was no reduction in arrhythmia death but there was a reduction in all-cause mortality. We discuss the mortality impact, rate of inappropriate shocks, compliance, and potential quality of life implications with the WCD. Finally, we present the evidence for WCD use in select populations (e.g., post-myocardial infarction, device extraction), and the current guideline recommendations for WCD use.

Who Should Receive a Wearable Defibrillator Vest at Hospital Discharge?

PURPOSE OF REVIEW

To discuss the role of wearable cardioverter defibrillator (WCD) vests in preventing sudden cardiac death (SCD) in at-risk populations.

RECENT FINDINGS

The impact of randomized-controlled trials with implantable cardioverter-defibrillators (ICD) therapy is well established in randomized clinical trials in ischemic cardiomyopathy. Although the benefits are not as clear in non-ischemic cardiomyopathy, meta-analyses show significant mortality benefits from immediate electrical cardioversion strategies. The role of WCDs in at-risk populations in whom ICD therapy is temporarily not indicated is not as well-established. Smaller cohort trials have shown efficacy in patients with newly-diagnosed cardiomyopathy, requiring temporary ICD explantation, and others with less common indications for WCD therapy. The Vest Prevention of Early Sudden Death Trial was a landmark randomized control study seeking to examine the benefits of WCD therapy in at-risk population, and although the primary endpoint of reducing arrhythmic death was not reached, the structure of the trial and significant differences in total mortality make a compelling case for continued use of WCD therapies in our healthcare systems.

The wearable cardioverter-defibrillator vest: Indications and ongoing questions

Multiple clinical trials have demonstrated the efficacy of implantable cardioverter-defibrillators (ICDs) for the prevention of sudden cardiac death (SCD) among specific high-risk populations. However, it remains unclear how to optimally treat those patients who are at elevated risk of cardiac arrest but are not among the presently identified groups proven to benefit from an ICD, are unable to tolerate surgical device implantation, or refuse invasive therapies. The wearable cardioverter-defibrillator (WCD) is an alternative antiarrhythmic device that provides continuous cardiac monitoring and defibrillation capabilities through a noninvasive, electrode-based system. The WCD has been shown to be highly effective at restoration of sinus rhythm in patients with a ventricular tachyarrhythmia, and one randomized trial using the WCD in patients with recent myocardial infarction at elevated risk for arrhythmic death reported a decrease in overall mortality despite no SCD mortality benefit. The current clinical indications for WCD use are varied and continue to evolve as experience with this technology increases.

Use of the wearable cardioverter-defibrillator (WCD) and WCD-based remote rhythm monitoring in a real-life patient cohort

The wearable cardioverter-defibrillator (WCD) was introduced to provide protection from sudden cardiac death (SCD) in patients with transiently elevated risk or during ongoing risk stratification. Benefits and clinical characteristics of routine WCD use remain to be assessed in larger patient populations. This study aims to identify determinants of WCD compliance, therapies, and inappropriate alarms in a real-life cohort. A total of 106 cases (68.9% male) were included between 11/2010 and 04/2016. WCD therapies, automatically recorded arrhythmia episodes, inappropriate WCD alarms, patient compliance, and outcome after WCD prescription were analyzed. Median duration of WCD use was 58.5 days. Average daily wearing time was 22.7 h. Compliance was reduced in patients ≤ 50 years. Three patients received WCD therapies (2.8%). In one case ventricular fibrillation (VF) was appropriately terminated with the first shock. Two patients received inappropriate WCD therapies due to WCD algorithm activation during ventricular pacemaker stimulation. One patient died of asystole while carrying a WCD (0.9%). Additional arrhythmias detected comprised self-terminating sustained ventricular tachycardia (VT; 2.8%), non-sustained VT (2.8%), and supraventricular arrhythmias (5.7%). Inappropriate WCD alarms due to over-/undersensing occurred in 77/106 patients (72.6%), of which 41 (38.7%) experienced ≥ 10 inappropriate WCD alarms during the prescription period. Thirteen patients (12.3%) displayed a mean of > 1 inappropriate alarms/day. WCD use was associated with high compliance and provided protection from VT/VF-related SCD. The majority of patients experienced inappropriate WCD alarms. Alterations in QRS morphology during pacemaker stimulation require consideration in WCD programming to prevent inappropriate alarms.

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.

Real world utilization and impact of the wearable cardioverter-defibrillator in a community setting

Introduction

The wearable cardioverter-defibrillator (WCD) is used in patients at risk for sudden cardiac death (SCD) but not immediate candidates for intracardiac defibrillator (ICD) implantation.

Methods

We performed a single center retrospective study of patients prescribed WCD upon hospital discharge from January 2002 to October 2015. Clinical characteristics were obtained from the hospital electronic database and device data from Zoll LifeVest database.

Results

Of 140 patients, 62% were men, 85.9% were African-American and mean age was 58.2 ± 15.5 years. Ischemic cardiomyopathy was present in 45 (32%) and non-ischemic cardiomyopathy in 64 patients (46%). Mean left ventricular ejection fraction (EF) was 0.28 ± 0.4. WCD was worn for 7657 patient-days (21 patient-years), with each patient using WCD for median of 43 days (IQR: 7–83 days), and daily mean use 17.3 ± 7.5 h. There were a total of 6 (4.2%) WCD shocks of which 2 (1.4%) were appropriate (one for VT, one for VF) and 4 (2.8%) were inappropriate (2 had supraventricular tachycardia, 2 had artifact). Two patients who received appropriate shocks were African-American with non-ischemic cardiomyopathy (EF<20%), non-sustained VT and wide QRS duration. Upon termination of WCD use, 45 (32%) received ICD while EF improved in 34 patients (32%).

Conclusions

In a predominantly minority, community setting, WCD compliance is high and use is effective in aborting SCD. However, inappropriate shocks do occur. A significant proportion of patients did not ultimately require ICD implantation suggesting this may be a cost-effective strategy in patients at risk of SCD.

The wearable cardioverter-defibrillator: current technology and evolving indications

The wearable cardioverter-defibrillator has been available for over a decade and now is frequently prescribed for patients deemed at high arrhythmic risk in whom the underlying pathology is potentially reversible or who are awaiting an implantable cardioverter-defibrillator. The use of the wearable cardioverter-defibrillator is included in the new 2015 ESC guidelines for the management of ventricular arrhythmias and prevention of sudden cardiac death. The present review provides insight into the current technology and an overview of this approach.

An appropriate shock of the wearable cardioverter-defibrillator in an outpatient setting

The wearable cardioverter-defibrillator (WCD) represents an alternative clinical approach to prevent sudden cardiac death as a bridge to therapy when making a final decision regarding the need for an implantable cardioverter defibrillator (ICD), especially in patients who are in the so-called gray zone according to ICD guidelines. Although the WCD system was introduced in Japan in April 2014, data regarding its usage and experience are limited. We report the first case of appropriate shock therapy using the WCD in an outpatient setting in Japan. We describe the case of a 22-year-old-woman who received the first case of successful appropriate WCD shock therapy in an outpatient setting in Japan.

Wearable cardioverter-defibrillator for prevention of sudden cardiac death after infected implantable cardioverter-defibrillator removal: A cost-effectiveness evaluation

BACKGROUND

Prevention of sudden cardiac arrest (SCA) after removal of an infected implantable cardioverter-defibrillator (ICD) is a challenging clinical dilemma. The cost-effectiveness of the wearable cardioverter-defibrillator (WCD) in this setting remains uncertain.

OBJECTIVE

The purpose of this study was to compare the cost-effectiveness of the WCD with discharge home, discharge to a skilled nursing facility, or inpatient monitoring for the prevention of SCA after infected ICD removal.

METHODS

A decision model was developed to compare the cost-effectiveness of use of the WCD to several different strategies for patients who undergo ICD removal. One-way and 2-way sensitivity analyses were performed to account for uncertainties.

RESULTS

In the base-case analysis, the incremental cost-effectiveness of the WCD strategy was $20,300 per life-year (LY) or $26,436 per quality-adjusted life-year (QALY) compared to discharge home without a WCD. Discharge to a skilled nursing facility and in-hospital monitoring resulted in higher costs and worse clinical outcomes. The incremental cost-effectiveness ratio was as low as $15,392/QALY if the WCD successfully terminated 95% of SCA events and exceeded the $50,000/QALY willingness-to-pay threshold if the efficacy was <69%.The WCD strategy remained cost-effective, assuming 5.6% 2-month SCA risk, as long as the time to reimplantation was at least 2 weeks.

CONCLUSION

The WCD likely is cost-effective in protecting patients against SCA after infected ICD removal while waiting for ICD reimplantation compared to keeping patients in the hospital or discharging them home or to a skilled nursing facility.