Medical Policy

This document addresses the wearable cardioverter defibrillator, an external vest-like garment device that is intended to perform the same tasks as an implantable cardioverter defibrillator (ICD), without requiring any invasive procedures.

Medically Necessary:

The wearable cardioverter defibrillator is considered medically necessary for individuals at high-risk of sudden cardiac arrest, who meet the following criteria (A and B):

1. Individuals must meet the medical necessity criteria for an implantable cardioverter defibrillator*; and
2. Individuals must have ONE of the following documented medical contraindications to implantation of an implantable cardioverter defibrillator (1, 2, or 3):
   1. Those awaiting a heart transplantation - on waiting list and meet medical necessity criteria for heart transplantation;** or
   2. Those with a previously implanted cardioverter defibrillator that requires explantation due to infection (for example, device pocket or lead infection, endocarditis) with waiting period before reimplantation of an implantable cardioverter defibrillator; or
   3. Those with an infectious process or other temporary condition (for example, recovery from surgery, lack of vascular access) that precludes immediate implantation of an implantable cardioverter defibrillator.

 * Refer to applicable implantable cardioverter defibrillator guidelines used by the plan
**Refer to TRANS.00033 Heart Transplantation

Investigational and Not Medically Necessary:

The wearable cardioverter defibrillator is considered investigational and not medically necessary when the criteria listed above are not met.

The U.S. Food and Drug Administration (FDA) granted clearance for the Lifecor Wearable Cardioverter Defibrillator (WCD^®) 2000 system via premarket application approval in December 2001, based on clinical data submitted to the FDA by the manufacturer, which has subsequently been published in the peer-reviewed literature, and referred to as the BIROAD and WEARIT studies (Feldman, 2004). The trials consisted of prospective, non-randomized studies, which compared the outcomes of the WCD with historical controls of subjects suffering sudden cardiac arrest (SCD) who called 911 emergency services. While this study demonstrated that the WCD could detect arrhythmias and appropriately deliver a counter shock, its long-term efficacy will depend on user compliance, and from a practical perspective, the WCD cannot be continuously worn. For example, the BIROAD and WEARIT studies included 289 subjects; there were 12 deaths reported, and 50% occurred in those who were either not wearing the device or wearing it inappropriately. Additionally, 68 of the 289 subjects discontinued wearing the device due to comfort issues or adverse reactions. Therefore, an implantable cardiac defibrillator (ICD) is considered standard care. A WCD would be considered an alternative to an ICD only in the small subset of individuals that have co-morbidities or other contraindications for an ICD. For example, individuals with an infected ICD requiring removal may benefit from a WCD worn during the limited interim period until an ICD can be reimplanted. Additionally, a small subset awaiting heart transplantation may be considered at high risk for arrhythmia, but are not candidates for an ICD due to co-morbidities. A WCD may be considered an alternative to an ICD in these individuals while they are on the heart transplant waiting list.

Additional prospective data from the Prospective Registry of Patients Using the Wearable Defibrillator (WEARIT-II) Registry were published in 2015. The WEARIT-II Registry enrolled 2000 subjects with ischemic (n=805, 40%), or nonischemic cardiomyopathy (n=927, 46%), or congenital/inherited heart disease (n=268) prescribed a WCD between August 2011 and February 2014. Clinical data were captured for arrhythmic events, ICD implantation, and improvement in left ventricular ejection fraction (LVEF). The median age was 62 years; the median LVEF was 25%. The median WCD wear time was 90 days with median daily use of 22.5 hours. There was a total of 120 episodes of sustained ventricular tachyarrhythmias in 41 individuals, of whom 54% received appropriate WCD shocks. Only 10 subjects (0.5%) received inappropriate WCD therapy. The rate of sustained ventricular tachyarrhythmias by 3 months was 3% among those individuals with ischemic cardiomyopathy and congenital/inherited heart disease and 1% among subjects with nonischemic disease (p=0.02). At the end of WCD use, 840 subjects (42%) were implanted with an ICD. The most frequent reason not to implant an ICD following WCD use was improvement in LVEF. The authors concluded that the WEARIT-II data demonstrated a high rate of sustained ventricular tachyarrhythmias at 3 months in at-risk individuals who were not eligible for an ICD and suggested that the WCD can be safely used to protect against potentially lethal cardiac events during this period of risk assessment (Kutyifa, 2015). Additional retrospective and database study of WCD use in subgroups of at-risk individuals with newly diagnosed cardiomyopathy (ischemic and nonischemic) were reported with results that indicate a possible role for the WCD in the first few months following a new diagnosis of cardiomyopathy. Further study is needed to inform about this possible use for the WCD (Salehi, 2016; Singh, 2015).

There has been interest in offering WCDs to individuals in the immediate post myocardial infarction (MI) period, when they are considered at high risk of arrhythmia. However, the Defibrillator in Acute Myocardial Infarction Trial (DINAMIT) demonstrated that an ICD is not indicated during this period (Hohnloser, 2004). The DINAMIT trial randomized 674 subjects to receive either an ICD or no ICD within 40 days of an MI. All participants had reduced ejection fractions (LVEF less than or equal to 35%) and impaired cardiac autonomic function. The primary outcome was death from any cause. The secondary outcome was death from arrhythmia. During a mean follow-up of 30 ± 13 months, there was no difference in overall mortality between the 2 groups. Of 120 subjects who died, 62 were in the ICD group, and 58 were in the control group. There were 12 deaths due to arrhythmia in the ICD group and 29 in the control group. There were 50 deaths from nonarrhythmic causes in the ICD group, however, and 29 in the control group. Nonarrhythmic cardiac causes accounted for 34 of the 50 deaths in the ICD group and 20 of the 29 nonarrhythmic deaths in the control group. The authors concluded that ICD therapy does not reduce overall mortality in high-risk subjects who have recently had an MI. Although ICD therapy was associated with a reduction in arrhythmia-related death, this was offset by an increase in nonarrhythmic-related death. While the nonrandomized BIROAD study investigated subjects treated with a WCD in the immediate post MI period, the results of the large randomized DINAMIT study provide higher grade evidence of the effects of WCD use in this period.

Two prospective, randomized, controlled trials compared the use of ICDs to that of conventional therapy: the Multi-Center Automatic Defibrillator Implantation Trial (MADIT; n=196) and the Multi-Center Automatic Defibrillator Implantation Trial II (MADIT II; n=1232). Both trials were conducted on subjects with coronary artery disease (CAD) who had experienced MIs and who had reduced LVEFs. Both trials were well designed and of good quality. The observed all-cause mortality rate in the conventionally treated group was somewhat lower in MADIT II (19.8%, with average follow-up at 20 months) than in MADIT (38.6%, with average follow-up at 27 months), suggesting some differences in the baseline mortality risk between these 2 populations. Both trials reported that ICD treatment resulted in more statistically significant reductions in all-cause mortality (primary endpoint) than conventional therapy did. The MADIT and MADIT II trials provide consistent evidence that individuals with CAD, prior MI and reduced LVEF who meet selection criteria for either trial have significantly reduced mortality when treated with an ICD (Moss, 1996). However, results of the MADIT II trial concluded that risk of SCD in those with LVEF less than or equal to 30% increases as a function of time from MI. The survival benefit associated with ICD placement appears to be greater for remote MI and remains substantial for up to 15 years after MI (Wilber, 2004).

Additional study of the WCD in the early high-risk period following an acute MI was conducted in the Vest Prevention of Early Sudden Death Trial and the VEST registry data. Both trials were sponsored by the manufacturer (Zoll Medical Corp.) and the University of California at San Francisco with results published in 2018. The VEST study analyzed individuals within 7 days of an MI who had ventricular dysfunction (LVEF ≤ 0.35) to determine if use of the WCD would impact mortality by reducing the incidence of SCD during the first 3 months following acute MI (NCT01446965). There were 1524 participants in the device group and 778 in the control group. The mean LVEF was 28% and 83.6% of participants underwent PCI during the index hospitalization. The primary outcome was the composite of sudden death or death from ventricular tachyarrhythmia at 90 days (arrhythmic death). Secondary outcomes included death from any cause and nonarrhythmic death. There was no significant difference between the 2 groups in the primary outcome of arrhythmic death (1.6% in the device group and 2.4% in the control group; relative risk, 0.67; 95% confidence interval [CI], 0.37 to 1.21; p=0.18). The total mortality was 3.1% in the device group, as compared with 4.9% in the control group (relative risk, 0.64; 95% CI, 0.43 to 0.98; uncorrected p=0.04). The rate of non-arrhythmic death was 1.4% in the device group and 2.2% in the control group (relative risk, 0.63; 95% CI, 0.33 to 1.19; uncorrected p=0.15). Of the 48 participants in the WCD group who died, 12 were wearing the device at the time of death including 9 of the 25 participants who experienced arrhythmic death. Of these 9 participants who died, 4 had had a ventricular tachyarrhythmia detected and had received appropriate shocks with conversion to sinus rhythm but with subsequent recurrent ventricular tachyarrhythmias or agonal rhythms. In the WCD group, 43 participants (2.8%) never wore the device after randomization; in the control group, 20 participants (2.6%) received the device outside the protocol. The power calculation assumed a device adherence rate of 70%, a goal that was met or exceeded in the first 2 weeks after randomization but that waned over time. A total of 20 participants in the WCD group (1.3%) received an appropriate shock; of these 20 subjects, 14 survived to 90 days indicating that not all successful defibrillations prolong survival. A total of 9 (0.6%) participants in the WCD group received an inappropriate shock. In an as-treated analysis, a significantly lower percentage of participants died when they were wearing the device than when they were not, a finding that remained significant even after the most conservative correction for multiple comparisons. Although this result is subject to bias, it suggests a benefit to wearing the device. The authors concluded that mortality at 90 days was 4.9% in the control group, despite 84% of the participants having undergone PCI for acute MI and more than 85% being treated with GDMT. The WCD did not result in a significantly lower rate of arrhythmic death than medical therapy during the first 90 days post-acute MI. It remains unclear how to reduce the risk of arrhythmic death beyond what is possible with appropriate medical therapy in the early period after MI before ICDs are indicated (Olgin, 2018).

There have been few additional studies of the WCD. Rao evaluated the short- and long-term outcomes of individuals with congenital structural heart disease (CSHD) and those with inherited arrhythmias (IA) who received a WCD for the prevention of SCD. The study population included 162 subjects with CSHD (n=43) and IA (n=119) who were prospectively followed in a nationwide manufacturer-sponsored registry from 2005 to 2010. The mortality rates were compared using Kaplan-Meier survival analysis. It was noted that subjects with CSHD had a greater frequency of left ventricular dysfunction (ejection fraction < 30%) than did those with IA (37% vs. 5%, respectively; p=0.002). The predominant indication for WCD was pending genetic testing in the IA group and transplant listing in the CSHD group. Compliance with the WCD was similar in the two groups (91%). WCD shocks successfully terminated 3 ventricular tachyarrhythmias in the subjects with IA during a median follow-up of 29 days of therapy (corresponding to 23 appropriate WCD shocks per 100 subject-years). No arrhythmias occurred in the subjects with CSHD during a median follow-up of 27 days, and no subjects died while actively wearing the WCD. At 1 year of follow-up, the survival rates were significantly lower among the subjects with CSHD (87%) than among those with IA (97%, p=0.02). The authors concluded that the data suggested the WCD can be safely used in high-risk adult individuals with IA and CSHD, although the subjects with IA showed a greater rate of ventricular tachyarrhythmias during therapy but significantly lower long-term mortality rates (Rao, 2011). Prospective randomized controlled trials are needed to confirm whether the observed results were due to the use of the WCD.

Use of the WCD has been suggested to reduce risk of SCD in pregnancy-associated peripartum cardiomyopathy (PPCM) that typically arises in the peripartum period and is marked by LV dysfunction and heart failure (HF). Thus far, PPCM is not precisely defined, and the timing of this condition is uncertain. The Heart Failure Association of the European Society of Cardiology (HFA/ESC) Study Group on PPCM provided an updated definition of PPCM as, “An idiopathic cardiomyopathy frequently presenting with HF secondary to LV systolic dysfunction (LVEF < 45%) towards the end of pregnancy or in the months following delivery, if no other cause of HF is found” (Bauersachs, 2016). This study group considered the WCD, “An interesting alternative for the prevention of SCD in the first months after diagnosis, until a definitive decision about ICD implantation can be made.” They recommended early consideration of the WCD in women with LVEF ≤ 35%. The 2018 ESC Guidelines for the Management of Cardiovascular Diseases during Pregnancy provided the same guidance as follows:

Given the high rate of improvement of LV function during optimal HF drug therapy, early implantation of an ICD in patients with newly diagnosed PPCM or DCM is not appropriate. A WCD may prevent SCD during the first 3–6 months after diagnosis, especially in patients with EF < 35%, allowing protected recovery from severe LV impairment (Regitz-Zagrosek, 2018).

To date, the majority of studies of PPCM incidence have been limited to case series, a single center case control study and population-based study. Preeclampsia, hypertension and multiple gestations predispose to PPCM. The majority of PPCM cases present postpartum, mostly in the week after delivery, but a small subset present during the second and third trimesters. The most common presentation includes signs and symptom of HF. There is limited data on the prevalence of ventricular arrhythmias in PPCM and effective treatment options. Further study is needed to clarify the risk factors for SCD in PPCM, as well as whether use of the WCD would improve clinical outcomes (Bello, 2013; Duncker, 2014; Saltzberg, 2012).

The ICD has been proven to be effective in reducing mortality in individuals with episodes of ventricular arrhythmias or in survivors of SCD, often seen in those with CAD. More recently, randomized studies, (that is, the MADIT I and MADIT II trials) have demonstrated that ICDs are effective prophylactic therapy in those who are considered at high risk for lethal arrhythmias, such as those with prior MI and reduced LVEF. ICDs consist of implantable leads in the heart that connect to a pulse generator implanted beneath the skin of the chest or abdomen. In the past, ICD placement required a thoracotomy, but current technology allows implantation with only a minor surgical procedure, with the cardiac leads placed percutaneously. Potential adverse effects of ICD placement are bleeding, infection, pneumothorax, and delivery of unnecessary counter shocks.

The WCD is an external device that is intended to perform the same tasks as an ICD, without requiring any invasive procedures. It consists of a vest that is worn continuously underneath the clothing. Part of this vest is the ‘electrode belt’ that contains the cardiac monitoring electrodes and the therapy electrodes that deliver a counter shock. The vest is connected to a monitor with a battery pack and alarm module that is worn on the belt. The monitor contains the electronics that interpret the cardiac rhythm and determine when a counter shock is necessary. The alarm module alerts the wearer to certain conditions by lights or voice messages. The U.S. Food and Drug Administration (FDA) gave clearance to the Lifecor WCD^® 2000 system via premarket application approval (PMA) in December 2001 for “Adult patients 18 years and older who are at risk for sudden cardiac arrest and are either not candidates for or refuse an implantable defibrillator.” The trade name of the WCD 2000 System was changed to LifeVest^® in 2002, and the LIFECOR business was acquired by ZOLL Medical Corporation (Philadelphia, PA) in 2006. On December 17, 2015, the FDA expanded its clearance of the LifeVest system to include individuals under the age of 18 when they have a chest circumference of 26 inches (66 centimeters) or greater and weight of 18.75 kilograms (41.3 pounds) or greater.

There are three peer-reviewed articles on the use of the LifeVest specifically in the pediatric population, which were described in the literature as follows:

One recent paper describes 4 pediatric individuals prescribed a WCD from a single site (Everitt, 2010). All carried a diagnosis of anthracycline-induced cardiomyopathy. None of these individuals had an appropriate or inappropriate shock. Two trial participants had documented noncompliance with wear, which resulted in failure to detect and treat a life-threatening arrhythmia in one. While no trial subjects received an appropriate treatment in this study, none received an inappropriate treatment despite the inappropriately detected rhythm caused by ECG noise. The paper concluded that the WCD is a short-term alternative for children at risk for SCD, who can be properly fit with the WCD, where the risk of ICD use is greater than the benefit.

In a paper by Collins (2010), 81 multi-site WCD individuals from 9-18 years old, and 103 subjects aged 19-21, were retrospectively reviewed. In subjects aged 19-21 years, there were five appropriate treatments in 2 subjects and one inappropriate treatment in a single subject. In subjects ≤ 18 years of age, there was one inappropriate therapy, due to sinus tachycardia and artifact, and one withholding of therapy, due to a device-device interaction. Compliance was generally similar to adults among these younger individuals, with an average daily use of 19 hours, and non-compliance or comfort issues only being recorded for 7-11% of trial participants. This paper concluded that the WCD could be an appropriate therapy for pediatric individuals who are at risk for SCD, as they had two appropriate treatments in their young adult population (age 19-21). However, they had no appropriate treatments in their pediatric population (age 9-18).

The third paper by LaPage (2008) detailed the fatal device-device interaction between the WCD and a unipolar epicardial pacemaker. Such interactions are not unique to pediatric individuals nor are they unique to wearable defibrillators, being extensively described in the ICD and AED literature. LifeVest manuals have included specific warnings about pacemaker interactions since the initial FDA approval. These warnings advise physicians to use appropriate caution when prescribing the LifeVest device to an individual who is dependent on a pacemaker. There was only one serious adverse event reported in the literature for pediatric subjects using the LifeVest.

The updated FDA premarket approval required that a post-approval study be performed as follows:

The study will consist of a serial, prospective data collection of patients under 18 years of age utilizing the LifeVest WCD who meet the proposed indication for the treatment of life-threatening arrhythmias. The data will be collected via medical order database, device generated records, and customer call reports for each device use. Patient demographics collected will include age, gender, and ICD-9 code(s) describing the patient’s condition. Performance information will include daily compliance with use, duration of use, appropriate therapy delivery, ECG recordings during appropriate therapy delivery, and any available description of the circumstances found within the Call Report Database. Safety data to be included are inappropriate defibrillation therapy delivery, ECG recordings during inappropriate therapy delivery and any available description of the circumstances found within the Call Report Database, and adverse events reported to ZOLL through the customer support or technical support departments. The data on the first 150 patients who meet the proposed indication will be collected and data will be obtained from the returned device (P010030/S056).

This study is the Vest Trial and VEST registry which is listed as completed; only one article has been published about the results, which has been detailed earlier in this document (Olgin, 2018).

On July 27, 2021, the ASSURE^® Wearable Cardioverter Defibrillator (A-WCD) System (Kestra Medical Technologies, Inc. Kirkland, WA) received FDA PMA approval. The ASSURE system is a non-invasive, external, individually worn device which is designed to automatically evaluate an electrocardiogram (ECG) for life-threatening ventricular arrhythmias and deliver a shock (defibrillation) to the heart to restore an effective rhythm. The approval order statement states that the ASSURE System “Is indicated for adult patients who are at risk for sudden cardiac arrest and are not candidates for, or refuse, an implantable defibrillator.” The ASSURE system is contraindicated for use in individuals with an active ICD. FDA clearance was based on results of the ASSURE WCD Clinical Evaluation – Detection and Safety Study (ACE-DETECT, NCT 03887052), which was a multicenter prospective, nonrandomized trial that evaluated the ASSURE WCD (A-WCD) for false alarm rates, wear compliance, and adverse events (AEs) in ambulatory subjects. Trial participants included subjects (n=130) who had an LVEF ≤ 40% and an active ICD. Detection was enabled in the A-WCD group and shock alarm markers were recorded, but shocks and shock alarms were disabled. All WCD episodes and ICD detected VT/VF episodes were adjudicated. The primary outcome measured the false positive shock alarm rate with a performance goal of one every 3.4 days (0.29 per patient‐day). Additional outcomes included a summary of A‐WCD and ICD detected episodes and individually self‐reported outcomes including perceived comfort, adverse events determined to be possibly related to use of the A-WCD and wear compliance. Trial participants were followed for 30 days with clinical follow‐up weekly by phone, and they returned for final follow‐up at the end of the 30‐day participation period. No ICD recorded VT/VF episodes meeting WCD detection criteria (≥ 170 bpm for ≥ 20 s) were missed by the A-WCD group during 3501 subject-days of use. The median wear was 31.0 days. Adverse events were mostly mild (skin irritation [19.4%] and musculoskeletal discomfort [8.5%]). Limitations noted by the authors included the small sample size and short-term follow-up which limited the generalizability of the results. Further, since the auditory/vibratory alarms and shocks were disabled, the reported wear compliance may not reflect clinical use when this functionality is enabled. The study concluded that the ASSURE WCD demonstrated a low false‐positive shock alarm rate, low self‐reported discomfort and no serious adverse events (Poole, 2022).

The FDA approval also requires an Annual Report that must include, separately for each model number (if applicable), the number of devices sold and distributed during the reporting period, including those distributed to distributors. The distribution data will provide necessary context for FDA to ascertain the frequency and prevalence of adverse events, as FDA evaluates the continued safety and effectiveness of the device. As part of the annual report, the number of devices returned to the applicant for normal end-of-life and alleged failures or malfunctions must be provided. A summary of information should be provided that includes defibrillation success and the number of shocks required for success, identification of any error codes or malfunctions during use and their related MDR number. Lastly, a listing of any safety alerts, technical service bulletins, user communications, or recalls for devices should be included (FDA, 2021).

In addition to the Annual Report requirements, the following data is also required in post-approval study (PAS) reports:

The ASSURE WCD Clinical Evaluation (ACE-PAS), will be conducted. The study will consist of active surveillance using real-world data collected in the ASSURE Registry. A total of 271 appropriate shock episodes for VT/VF is required to provide the required level of statistical precision for the primary effectiveness outcome. It is estimated that a total of 5,179 patients will be required to provide data on 271 appropriate shock episodes. The device will be used temporarily (days of use), and the data will be obtained from that period of use. No additional patient follow-up is required.

The primary safety outcome measures the inappropriate shocks per patient-month of use (total inappropriate shocks/cumulative months of device use for all patients) ≤ 0.0075. The FDA requires the first report be provided after 500 patients. Following the initial report, subsequent reports will be provided every six months until the required sample size is achieved, and a final report is generated. PAS Progress Reports must be submitted every six months until subject enrollment has been completed, and annually thereafter. If milestones are not met, quarterly enrollment status reports (i.e., every 3 months) must be submitted in addition to periodic (6-months) PAS Progress Reports, until FDA states otherwise (FDA, 2021).

Cardiac arrhythmia: A disturbance in the electrical activity of the heart that manifests as an abnormality in the heart rate or heart rhythm. Individuals with arrhythmias may experience a wide variety of symptoms ranging from palpitations to fainting.

Coronary artery: A pair of vessels that supply blood to the myocardium (middle layer of the walls of the heart).

Coronary artery disease (CAD): This condition involves narrowing of the coronary arteries that is sufficient enough to prevent adequate blood supply to the myocardium.

Defibrillation: A treatment in which an electronic device sends an electric shock to the heart to stop an extremely rapid, irregular heartbeat, in order to restore the normal heart rhythm.

Ejection fraction (also referred to as left ventricular ejection fraction [LVEF]): A measure of ventricular contractility.

Electrophysiologic study (EPS) of the heart: This is a test of the electrical conduction system of the heart (the system that generates the heartbeat).

Fibrillation: This term refers to very rapid contractions or twitching of small muscle fibers in the heart.

Tachycardia: An abnormally rapid heartbeat.

Ventricle: One of two lower chambers of the heart.

The following codes for treatments and procedures applicable to this document are included below for informational purposes. Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy. Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

When services may be Medically Necessary when criteria are met:

When services are Investigational and Not Medically Necessary:
For the procedure codes listed above when criteria are not met.

Peer Reviewed Publications:

1. Adler A, Halkin A, Viskin S. Wearable cardioverter-defibrillators. Circulation. 2013; 127(7):854-860.
2. Auricchio A, Klein H, Geller CJ, et al. Clinical efficacy of the wearable cardioverter defibrillator in acutely terminating episodes of ventricular fibrillation. Am J Cardiol. 1998; 81(10):1253-1256.
3. Barsheshet A, Kutyifa V, Vamvouris T, et al. Study of the wearable cardioverter defibrillator in advanced heart-failure patients (SWIFT). J Cardiovas Electrophys. 2017; 28(7):778-784.
4. Beauregard LA. Personal security: clinical applications of the wearable defibrillator. Pacing Clin Electrophysiol. 2004; 27(1):1-3.
5. Bello N, Rendon IS, Arany Z. The relationship between pre-eclampsia and peripartum cardiomyopathy: a systematic review and meta-analysis. J Am Coll Cardiol. 2013; 62:1715-1723.
6. Bigger JT Jr. Prophylactic use of implanted cardiac defibrillators in patients at high risk for ventricular arrhythmias after coronary artery bypass surgery. The CABG-PATCH Trial Investigators. N Engl J Med. 1997; 337(22):1569-1575.
7. Boehmer JP. Device therapy for heart failure. Am J Cardiol. 2003; 91(6A):53D-59D.
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9. Chung MK, Szymkiewicz SJ, Shao M, et al. Aggregate national experience with the wearable cardioverter-defibrillator: event rates, compliance, and survival. J Am Coll Cardiol. 2010; 56(3):194-203.
10. Collins KK, Silva JN, Rhee EK, Schaffer MS. Use of a wearable automated defibrillator in children compared to young adults. Pacing and Clinical Electrophysiology. 2010; 33(9):1119-1124.
11. Duncker D, Haghikia A, Konig T, et al. Risk for ventricular fibrillation in peripartum cardiomyopathy with severely reduced left ventricular function-value of the wearable cardioverter/defibrillator. Eur J Heart Fail. 2014; 16(12):1331-1336.
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14. Epstein AE, Abraham WT, Bianco N, et al. Wearable cardioverter-defibrillator use in patients perceived to be at high risk early post myocardial infarction. J Am Coll Cardiol. 2013; 62(21):2000-2007.
15. Erath JW, Vamos M, Benz AP, Hohnloser SH. Usefulness of the WCD in patients with suspected tachymyopathy. Clin Res Cardiol. 2018; 107(1):70-75.
16. Erath JW, Vamos M, Sirat AS, Hohnloser SH. The wearable cardioverter-defibrillator in a real-world clinical setting: experience in 102 consecutive patients. Clin Res Cardiol. 2017; 106(4):300-306.
17. Everitt MD, Saarel EV. Use of the wearable external cardiac defibrillator in children. Pacing Clin Electrophysiol. 2010; 33(6):742-746.
18. Feldman AM, Klein H, Tchou P, et al. Use of a wearable defibrillator in terminating tachyarrhythmias in patients at high risk for sudden death: results of the WEARIT/BIROAD. Pacing Clin Electrophysiol. 2004; 27(1):4-9.
19. Goldenberg I, Erath JW, Russo AM, et al. Sex differences in arrhythmic burden with the wearable cardioverter-defibrillator. Heart Rhythm. 2021; 18(3):404-410.
20. Hohnloser SH, Kuck KH, Dorian P, et al. Prophylactic use of an implantable cardioverter-defibrillator after acute myocardial infarction. N Engl J Med. 2004; 351(24):2481-2488.
21. Kao AC, Krause SW, Handa R, et al.; Wearable defibrillator use In heart Failure (WIF) Investigators. Wearable defibrillator use in heart failure (WIF): results of a prospective registry. BioMed Cardiovas Disord. 2012; 12:123.
22. Klein HU, Goldenberg I, Moss AJ. Risk stratification for implantable cardioverter defibrillator therapy: the role of the wearable cardioverter-defibrillator. Eur Heart J. 2013; 34(29):2230-2242.
23. Klein HU, Meltendorf U, Reek S, et al. Bridging a temporary high risk of sudden arrhythmic death. Experience with the wearable cardioverter defibrillator (WCD). Pacing Clin Electrophysiol. 2010; 33(3):353-367.
24. Kondo Y, Linhart M, Andrié RP, Schwab JO. Usefulness of the wearable cardioverter defibrillator in patients in the early post-myocardial infarction phase with high risk of sudden cardiac death: a single-center European experience. J Arrhythm. 2015; 31(5):293-295.
25. Kovacs B, Reek S, Krasniqi N, et al. Extended use of the wearable cardioverter defibrillator: Which patients are most likely to benefit? Cardiol Res Pract. 2018 Nov 29; 2018:7373610.
26. Kutyifa V, Moss AJ, Klein H, et al. Use of the wearable cardioverter defibrillator in high-risk cardiac patients: data from the Prospective Registry of Patients Using the Wearable Cardioverter Defibrillator (WEARIT-II Registry). Circulation. 2015; 132(17):1613-1619.
27. Lackermair K, Schuhmann CG, Kubieniec M, et al. Impairment of quality of life among patients with wearable cardioverter defibrillator therapy (LifeVest^®): A preliminary study. Biomed Res Int. 2018; 6028494.
28. LaPage MJ, Canter CE, Rhee EK. A fatal device-device interaction between a wearable automated defibrillator and a unipolar ventricular pacemaker. Pacing Clin Electrophysiol. 2008; 31(7):912-915.
29. Leyton-Mange JS, Hucker WJ, Mihatov N, et al. Experience with wearable cardioverter-defibrillators at 2 academic medical centers. JACC Clin Electrophysiol. 2018; 4(2):231-239.
30. Olgin JE, Lee BK, Vittinghoff E, et al. Impact of wearable cardioverter-defibrillator compliance on outcomes in the VEST trial: As treated and per protocol analyses. J Cardiovasc Electrophysiol. 2020; 31:1009-1018.
31. Olgin JE, Pletcher MJ, Vittinghoff E, et al; VEST Investigators. Wearable cardioverter-defibrillator after myocardial infarction. N Engl J Med. 2018; 379(13):1205-1215.
32. Opreanu M, Wan C, Singh V, et al. Wearable cardioverter-defibrillator as a bridge to cardiac transplantation: a national database analysis. J Heart Lung Transplant. 2015; 34(10):1305-1309.
33. Poole JE, Gleva MJ, Birgersdotter-Green U, et al. A wearable cardioverter defibrillator with a low false alarm rate. J Cardiovasc Electrophysiol. 2022; 33(5):831-842.
34. Pouleur AC, Barkoudah E, Uno H, et al.; VALIANT Investigators. Pathogenesis of sudden unexpected death in a clinical trial of patients with myocardial infarction and left ventricular dysfunction, heart failure, or both. Circulation. 2010; 122(6):597-602.
35. Rao M, Goldenberg I, Moss AJ, et al. Wearable defibrillator in congenital structural heart disease and inherited arrhythmias. Am J Cardiol. 2011; 108(11):1632-1638.
36. Reek S, Geller JC, Meltendorf U, et al. Clinical efficacy of a wearable defibrillator in acutely terminating episodes of ventricular fibrillation using biphasic shocks. Pacing Clin Electrophysiol. 2003; 26(10):2016-2022.
37. Reek S, Meltendorf U, Geller JC, et al. The wearable cardioverter defibrillator (WCD) for the prevention of sudden cardiac death – a single center experience. Z Kardiol. 2002; 91(12):1044-1052 (abstract available in English; article in German).
38. Salehi N, Nasiri M, Bianco NR, et al. The wearable cardioverter defibrillator in nonischemic cardiomyopathy: a US National Database Analysis. Can J Cardiol. 2016; 32(10):1247.e1-1247.
39. Saltzberg MT, Szymkiewicz S, Bianco NR. Characteristics and outcomes of peripartum versus nonperipartum cardiomyopathy in women using a wearable cardiac defibrillator. J Card Fail. 2012; 18:21-27.
40. Sana F, Eric M, Isselbacher JP, et al. Wearable devices for ambulatory cardiac monitoring. JACC State-of-the-Art Review. JACC. 2020; (13):1582-1592.
41. Sheppard R1, Mather PJ, Alexis JD, et al. Implantable cardiac defibrillators and sudden death in recent onset nonischemic cardiomyopathy: results from IMAC2. J Card Fail. 2012; 18(9):675-681.
42. Singh M, Wang NC, Jain S, et al. Utility of the wearable cardioverter-defibrillator in patients with newly diagnosed cardiomyopathy: a decade-long single-center experience. J Am Coll Cardiol. 2015; 66(23):2607-2613.
43. Sinha AM, Bense J, Hohenforst-Schmidt W. The impact of wearable cardioverter-defibrillator use on long-term decision for implantation of a cardioverter-defibrillator in a semirural acute care hospital. J Interv Card Electrophysiol. 2021; 62(2):401-407.
44. Solomon SD, Zelenkofske S, McMurray JJ, et al. Sudden death in patients with myocardial infarction and left ventricular dysfunction, heart failure, or both. N Engl J Med. 2005; 352(25):2581-2588.
45. Steinbeck G, Andresen D, Seidl K, et al.; IRIS Investigators. Defibrillator implantation early after myocardial infarction. N Engl J Med. 2009; 361(15):1427-1436.
46. Verdino RJ. The wearable cardioverter-defibrillator. J Am Coll Cardiol. 2010; 56(3):204-205.
47. Wäßnig NK1, Günther M2, Quick S2, et al. Experience with the wearable cardioverter-defibrillator in patients at high risk for sudden cardiac death. Circ. 2016; 134(9):635-643.
48. Wilber DJ, Zareba W, Hall WJ, et al. Time dependence of mortality risk and defibrillator benefit after myocardial infarction. Circulation. 2004; 109(9):1082-1084.
49. Zei PC. Is the wearable cardioverter-defibrillator the answer for early post-myocardial infarction patients at risk for sudden death? Mind the gap. J Am Coll Cardiol. 2013; 62(21):2008-2009.
50. Zishiri ET, Williams S, Cronin EM, et al. Early risk of mortality after coronary artery revascularization in patients with left ventricular dysfunction and potential role of the wearable cardioverter defibrillator. Circ Arrhythm Electrophysiol. 2013; 6(1):117-128.

Government Agency, Medical Society, and Other Authoritative Publications:

1. Al-Khatib SM, Stevenson WG, Ackerman MJ, et al. 2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: Executive Summary: a Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation. 2017; 138(13).
2. Amsterdam EA, Wenger NK, Brindis RG, et al. 2014 AHA/ACC Guideline for the management of patients with non-ST-elevation acute coronary syndromes: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 2014; 130(25):e344-e426.
3. Bauersachs J, Arrigo M, Hilfiker-Kleiner D, et al. Current management of patients with severe acute peripartum cardiomyopathy: Practical guidance from the Heart Failure Association of the European Society of Cardiology Study Group on peripartum cardiomyopathy. Eur J Heart Fail. 2016; 18:1096-1105.  
4. Blue Cross Blue Shield Association. Wearable cardioverter-defibrillator as a bridge to implantable cardioverter-defibrillator treatment. TEC Assessment, 2010; 25(2).
5. Ellenbogen KA, Koneru JN, Sharma PS, et al. Benefit of the wearable cardioverter-defibrillator in protecting patients after implantable-cardioverter defibrillator explant. Results from the National Registry. JACC Clin Electrophysiol. 2017; 3:243-250.
6. Epstein AE, Abraham WT, Bianco NR, et al. Wearable cardioverter-defibrillator use in patients perceived to be at high risk early post-myocardial infarction. J Am Coll Cardiol. 2013; 62(21):2000-2007.
7. Epstein AE, DiMarco JP, Ellenbogen KA, et al. ACC/AHA/HRS 2008 Guidelines for device-based therapy of cardiac rhythm abnormalities: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the ACC/AHA/NASPE 2002 Guideline Update for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices) Developed in Collaboration with the American Association for Thoracic Surgery and Society of Thoracic Surgeons. J Am Coll Cardiol. 2008; 51(21):e1-62.
8. Goldberger JJ, Cain ME, Hohnloser SH, et al. American Heart Association/American College of Cardiology Foundation/Heart Rhythm Society Scientific Statement on Noninvasive risk stratification techniques for identifying patients at risk for sudden cardiac death. A Scientific Statement from the American Heart Association Council on Clinical Cardiology Committee on Electrocardiography and Arrhythmias and Council on Epidemiology and Prevention. J Am Coll Cardiol. 2008; 52(14):1179-1199.
9. Gronda E, Bourge RC, Costanzo MR, et al. Heart rhythm considerations in heart transplant candidates and considerations for ventricular assist devices: International Society for Heart and Lung Transplantation Guidelines for the Care of Cardiac Transplant Candidates—2006. J Heart Lung Trans. 2006; 25(9):1043-1056.
10.  Jessup M, Abraham WT, Casey DE, et al. writing on behalf of the 2005 Guideline Update for the Diagnosis and Management of Chronic Heart Failure in the Adult Writing Committee. 2009 Focused Update: ACCF/AHA guidelines for the diagnosis and management of heart failure in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2009; 119(a4):1977-2016.
11. Kestra^® Medical Technologies, Inc. ASSURE WCD Clinical Evaluation – Detection and Safety Study (ACE-DETECT). NCT 03887052. Last updated September 3, 2020. Available at: https://clinicaltrials.gov/ct2/show/NCT03887052?term=NCT+03887052&draw=2&rank=1. Accessed on June 26, 2023.
12. Kushner FG, Hand M, Smith SC, et al. 2009 Focused Updates: ACC/AHA Guidelines for the management of patients with ST-elevation myocardial infarction (Updating the 2004 Guideline and 2007 Focused Update) and ACC/AHA/SCAI Guidelines on Percutaneous Coronary Intervention (Updating the 2005 Guideline and 2007 Focused Update): a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2009; 54(23):2205-2241.
13. Kusumoto FM, Calkins H, Boehmer J, et al. HRS/ACC/AHA expert consensus statement on the use of implantable cardioverter-defibrillator therapy in patients who are not included or not well represented in clinical trials. J Am Coll Cardiol. 2014; 64(11):1143-1177.
14. Piccini JP, Allen LA, Kudenchuk PJ, et al. Wearable cardioverter-defibrillator therapy for the prevention of sudden cardiac death: a Science Advisory from the American Heart Association. Circulation. 2016; 133(17):1715-1727.
15. Priori SG, Blomström-Lundqvist C, Mazzanti A, et al. 2015 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: the Task Force for the Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death of the European Society of Cardiology (ESC). Endorsed by: Association for European Pediatric and Congenital Cardiology (AEPC). Eur Heart J. 2015; 36(41):2793-2867.
16. Regitz-Zagrosek V, Roos-Hesselink JW, Bauersachs J, et al. 2018 European Society of Cardiology (ESC) Guidelines for the management of cardiovascular diseases during pregnancy. Eur Heart J. 2018; 39(34):3165-3241.  
17.  U.S. Food and Drug Administration. Center for Devices and Radiological Health (CDRH). 510(k) Premarket Notification Database. Available at: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfPMA/pma.cfm. Accessed on July 9, 2023.
    • ASSURE Wearable Cardioverter Defibrillator (WCD) System. No. P200037. Rockville, MD: FDA. July 27, 2021.
    • LifeVest^® System Summary of Safety and Effectiveness. No. P010030/S056. Rockville, MD: FDA. December 17, 2015.
18.  Uyei J, Braithwaite RS. Effectiveness of wearable defibrillators: systematic review and quality of evidence. Int J Technol Assess Health Care. 2014; 30(2):194-202.
19. Zipes DP, Camm AJ, Borggrefe M, et al. ACC/AHA/ESC 2006 Guidelines for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: a report of the American College of Cardiology/American Heart Association Task Force and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Develop Guidelines for Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death). Eur Heart J. 2006; 27(17):2099-2140.

1.  American Heart Association information. Available at: http://www.americanheart.org/ Accessed on June 26, 2023.

ASSURE WCD System
Cardioverter Defibrillators
Lifecor WCD 2000 System
LifeVest
Sudden Cardiac Arrest
Wearable Cardioverter Defibrillators

The use of specific product names is illustrative only. It is not intended to be a recommendation of one product over another, and is not intended to represent a complete listing of all products available.