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 (WCD) is considered medically necessary for individuals at high-risk of sudden cardiac arrest, who meet the following criteria:

1. Individuals must meet the medical necessity criteria for an implantable cardioverter defibrillator* (ICD);
   AND
2. Individuals must have ONE of the following documented medical contraindications to ICD implantation:
   1. Those awaiting a heart transplantation - on waiting list and meet medical necessity criteria for heart transplantation;** or
   2. Those with a previously implanted ICD that requires explantation due to infection with waiting period before ICD reinsertion; or
   3. Those with an infectious process or other temporary condition that precludes initial implantation of an ICD.
       * Refer to SURG.00033 Implantable Cardioverter-Defibrillator (ICD).
      **Refer to TRANS.00033 Heart Transplantation.

Investigational and Not Medically Necessary:

The wearable cardioverter defibrillator (WCD) is considered investigational and not medically necessary for all other indications, including but not limited to, the following:

• Individuals with a history of an acute myocardial infarction (MI) within the last 40 days;
• Individuals with drug-refractory class IV congestive heart failure (CHF) who are not candidates for heart transplantation;
• Individuals with a history of psychiatric disorders that interfere with the necessary care and follow-up;
• Individuals in whom a reversible triggering factor for ventricular tachycardia/ventricular fibrillation (VT/VF) can be definitely identified, such as ventricular tachyarrhythmias in evolving acute myocardial infarction or electrolyte abnormalities;
• Individuals with terminal illnesses.

The U.S. Food and Drug Administration (FDA) approved 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 the gold standard and, as such, a WCD would be considered an alternative to an ICD only in the small subset 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.

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 mortality from any cause, and 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 two 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. 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 a higher level of evidence, which may be extrapolated to WCD.

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 = 1,232). 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 two 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 ICDs than when given conventional therapy (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 (greater than or equal to) 15 years after MI.  "There appeared to be a trend toward increasing survival benefit associated with ICD therapy as time from MI increased." These findings can also be extrapolated to use of the WCD device (Wilber, 2004).

To date, 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 up in a nationwide 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 2 groups (91%). WCD shocks successfully terminated three 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).

The implantable cardioverter defibrillator (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 coronary artery disease (CAD). More recently, randomized studies, (i.e., 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 countershocks.

The wearable cardioverter defibrillator (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 countershock. 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 countershock 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 in December 2001 for "Adult patients 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.

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:  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:  A measure of ventricular contractility. 

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

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

Tachycardia:  An abnormally rapid heart beat.

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; or when the code describes a procedure indicated in the Position Statement section as investigational and not medically necessary.

Peer Reviewed Publications:

1. 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.
2. Beauregard LA. Personal security: clinical applications of the wearable defibrillator.  Pacing Clin Electrophysiol. 2004; 27(1):1-3.
3. Bigger JT.  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.
4. Boehmer JP. Device therapy for heart failure. Am J Cardiol. 2003; 91(suppl):53D-59D.
5. 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.
6. 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.
7. 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.
8. 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.
9. Pouleur AC, Barkoudah E, Uno H, VALIANT Investigators, et al.  Pathogenesis of sudden unexpected death in a clinical trial of patients with myocardial infarction and left ventricular dysfunction, heart failure, or both. Circ. 2010; 122(6):597-602.
10. Rao M, Goldenberg I, Moss AJ, et al.  Wearable Defibrillator in Congenital Structural Heart Disease and Inherited Arrhythmias. Am J Cardiol. 2011 Sep 3. [Epub ahead of print]
11. 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.
12. 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).
13. 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.
14. 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.

Government Agency, Medical Society, and Other Authoritative Publications:

1. Antman EM, Hand M, Armstrong PW, et al. 2007 Focused Update of the ACC/AHA 2004 Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction: American College of Cardiology/American Heart Association Task Force on Practice Guidelines Developed in Collaboration With the Canadian Cardiovascular Society Endorsed by the American Academy of Family Physicians 2007 Writing Group to Review New Evidence and Update the ACC/AHA 2004 Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction, Writing on Behalf of the 2004 Writing Committee. J Am Coll Cardiol. 2008; 51:210-247.  Available at: http://content.onlinejacc.org/cgi/reprint/51/2/210.pdf.  Accessed on September 20, 2011.
2. Blue Cross Blue Shield Association.  Wearable cardioverter-defibrillator as a bridge to implantable cardioverter-defibrillator treatment. TEC Assessment, 2010; 25(2).
3. Bonow RO, Carabello BA, Chatterjee K, et al. 2008 Focused Update Incorporated Into the ACC/AHA 2006 Guidelines for the Management of Patients With Valvular Heart Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 1998 Guidelines for the Management of Patients With Valvular Heart Disease) Endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. J Am Coll Cardiol. 2008; 52:1-142. Available at: http://content.onlinejacc.org/cgi/content/full/52/13/e1.  Accessed on September 17, 2011.
4. 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; 51:1-62.  Available at: http://content.onlinejacc.org/cgi/content/full/51/21/e1#SEC6. Accessed on September 17, 2011.
5. Feldman MD. Wearable Cardioverter Defibrillator for Patients at risk for Sudden Cardiac Arrest:  A Technology Assessment.  California Technology Assessment Forum^™.  San Francisco, CA.  March 11, 2009.  Available at:  http://www.ctaf.org/content/assessment/detail/987.  Accessed on September 17, 2011.
6. Goldberger JJ, Cain ME, Kadish AH, 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; 52:1179-1199. Available at: http://content.onlinejacc.org/cgi/content/full/j.jacc.2008.05.003.  Accessed on September 17, 2011.
7. Gregoratos G, Abrams J, Epstein AE, et al. ACC/AHA/NASPE 2002 guideline update for implantation of   cardiac pacemakers and antiarrhythmic devices: a Report of the American College of Cardiology/ American Heart Association Task Force on Practice Guidelines (ACC/AHA/ NASPE Committee on Pacemaker Implantation). 2002.  Available at: http://content.onlinejacc.org/cgi/reprint/40/9/1703.pdf.  Accessed on September 17, 2011.
8. 8.   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; 25:1043-1056.  Available at:    http://www.jhltonline.org/article/PIIS1053249806004578/fulltext. Accessed on September 17, 2011.
9. 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; 53:1343-1382. Available at:  http://content.onlinejacc.org/cgi/reprint/53/15/1343.pdf.  Accessed on September 17, 2011.
10. National Heart, Lung and Blood Institute (NHLBI) for the PREDICTS portion only, Medtronic, ZOLL Lifecor, General Electric.  Evaluating the Effectiveness of the LifeVest Defibrillator and Improving Methods for Determining the Use of Implantable Cardioverter Defibrillators (VEST/PREDICTS).  NCT00628966. Last updated July 6, 2011. Available at:  http://www.clinicaltrials.gov/ct2/show/NCT00628966?term=Vest+Prevention+of+Early+Sudden+Death+and+PREDiction+of+ICD&rank=1. Accessed on September 17, 2011.
11. U.S. Food and Drug Administration. Center for Devices and Radiological Health (CDRH) 510(k) Premarket Notification Database.  Lifecor WCD^® 2000 System Summary of Safety and Effectiveness. No. P010030. Rockville, MD: FDA. December 18, 2001. Available at: http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfPMA/pma.cfm?id=759.  Accessed on September 17, 2011. 
12. U.S. Food and Drug Administration Center for Devices and radiological Health (CDRH) 510(k) Premarket Notification Database.  Phillips HeartStart Home Defibrillator.  No. K040904.  Rockville, MD:FDA. September 16, 2004.  Available at: http://www.accessdata.fda.gov/cdrh_docs/pdf4/k040904.pdf.  Accessed on September 21, 2011.       
13. 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). J Am Coll Cardiol. 2006; 48:e247-e346.  Available at:  http://content.onlinejacc.org/cgi/reprint/48/5/e247.pdf.  Accessed on September 17, 2011.
14. Zoll Medical Corporation.  Study of the Wearable Defibrillator in Heart-Failure Patients (SWIFT).  NCT01326624.  Last updated March 30, 2011.  Available at:  http://clinicaltrials.gov/ct2/show/NCT01326624. Accessed on September 21, 2011.

1. American Heart Association information.  Available at: http://www.americanheart.org/  Accessed on September 17, 2011. 

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.