What is the proper use and management of a life vest (wearable cardioverter-defibrillator) for individuals at risk of cardiac events?

Proper Use and Management of a Life Vest (Wearable Cardioverter-Defibrillator)

The wearable cardioverter-defibrillator (WCD) or "life vest" is a highly effective temporary protection device for individuals at risk of sudden cardiac death, with studies showing 99% first shock efficacy and 90% post-shock survival. 1

What is a Life Vest?

• A life vest is a vest-like device worn under clothing that continuously monitors heart rhythm and automatically delivers an electric shock when ventricular fibrillation (VF) or ventricular tachycardia (VT) is detected 1
• The device is designed to be worn continuously, 24 hours per day, except during bathing or showering 1
• FDA-approved for patients who are "at risk for sudden cardiac arrest and are not candidates for or refuse an implantable defibrillator" 1

Indications for Life Vest Use

Strongly Recommended (Class IIa):

• Patients with an ICD and history of sudden cardiac arrest or sustained ventricular arrhythmia requiring temporary ICD removal (e.g., due to infection) 1
• This allows hospital discharge with protection until clinical situation permits ICD reimplantation 1

Reasonable Considerations (Class IIb):

• Patients awaiting cardiac transplantation 1
• Patients with left ventricular ejection fraction ≤35% within 40 days after myocardial infarction 1, 2
• Newly diagnosed non-ischemic cardiomyopathy with LVEF ≤35% before reassessment 1, 2
• After recent revascularization (within 90 days) 1
• Patients with myocarditis or secondary cardiomyopathy 1
• Patients with systemic infection preventing immediate ICD implantation 1

Proper Use Instructions

Daily Wearing Requirements:

• The device must be worn continuously (24 hours/day) except during bathing/showering 1
• Proper patient education is critical for compliance, as effectiveness depends on consistent wear 2
• Typical wear period ranges from 1-3 months until reassessment of cardiac function or until permanent ICD implantation 1, 2

Response to Alarms:

• The device has a progressive alarm system that alerts before shock delivery 3
• If alert sounds, patients should:
  1. Sit or lie down immediately to prevent injury from falling during potential shock 3
  2. Allow bystanders to move away before shock delivery 3
  3. Press response buttons if alert is false (conscious patients only) 3

Maintenance Requirements:

• Change batteries as indicated by device alerts 3
• Keep electrode pads clean and properly positioned against skin 3
• Regularly check for wear and tear of components 3
• Maintain proper fit of the vest for optimal electrode contact 3

Effectiveness and Outcomes

• Among 3,569 patients using the device, 80 VT/VF events occurred in 59 patients (1.7% per patient-year) 1
• First shock efficacy is remarkably high at 99% 1
• Post-shock survival rate is approximately 90% 1
• Overall inappropriate shock rate is approximately 2% 1
• A recent meta-analysis of 40 studies with 59,647 adults showed a pooled incidence of appropriate WCD intervention of 3% 4

Common Pitfalls and Limitations

• Poor compliance: Effectiveness depends entirely on patient adherence to wearing the device continuously 2, 4
• Inappropriate shocks: Can occur in approximately 2% of patients 1
• Skin irritation: Extended wear can cause discomfort or skin issues 3
• Bathing/showering vulnerability: Patients are unprotected during these times 1
• Psychological impact: Some patients experience anxiety or reduced quality of life while wearing the device 2
• Limited evidence: Only one randomized clinical trial (VEST) supports its use 2

Special Considerations

• Life-threatening arrhythmias are higher during early follow-up (≤60 days) after cardiac events, making this period particularly critical for consistent wear 4
• Young adults (16-45 years) with inherited arrhythmia syndromes present unique challenges due to potentially decades of device use 5
• The device may serve as a bridge to transplant even in patients with anticipated survival <1 year without transplant 1
• For patients after non-ST-elevation acute coronary syndromes with significantly reduced left ventricular ejection fraction, a life vest may be considered while awaiting reassessment for permanent ICD placement (typically at ≥40 days post-discharge) 1

By following these guidelines for proper use and management of a life vest, patients at risk for sudden cardiac death can receive effective temporary protection until their clinical situation improves or a more permanent solution is implemented.