Indications for the LifeVest (Wearable Cardioverter-Defibrillator)
The LifeVest wearable cardioverter-defibrillator is indicated primarily for temporary protection in patients at high risk for sudden cardiac death who are not immediate candidates for implantable cardioverter-defibrillator placement. 1, 2
Primary Indications (Class IIa, Level B-NR)
- Patients with an ICD and history of sudden cardiac arrest or sustained ventricular arrhythmia requiring ICD removal (e.g., due to infection) 1, 2
- Provides continuous protection until a new ICD can be implanted
- Reasonable for prevention of sudden cardiac death
Secondary Indications (Class IIb, Level B-NR)
- Patients at increased risk of sudden cardiac death but not eligible for immediate ICD implantation 1, 2:
- Awaiting cardiac transplantation
- LVEF ≤35% within 40 days after myocardial infarction
- Newly diagnosed non-ischemic cardiomyopathy
- Within 90 days of coronary revascularization
- Myocarditis or secondary cardiomyopathy
- Systemic infection
Specific Clinical Scenarios
Post-ICD Explantation
- Indicated when ICD removal is required (typically due to infection)
- Provides continuous protection during the vulnerable period before reimplantation 2
- First-line recommendation in this scenario with strong evidence support
Post-Myocardial Infarction
- Consider for patients with LVEF ≤35% who are within the 40-day waiting period for ICD implantation
- Allows time to determine if LVEF will improve with medical therapy 2
- Reassessment of cardiac function should occur at ≥40 days post-MI
Newly Diagnosed Cardiomyopathy
- Consider for patients with newly diagnosed non-ischemic cardiomyopathy with LVEF ≤35%
- Allows time for optimization of guideline-directed medical therapy
- Left ventricular function may improve, potentially eliminating need for permanent ICD 2
Heart Transplant Candidates
- Reasonable option for patients awaiting heart transplantation
- May be preferable to ICD implantation in this population 3
- Registry data shows 67% of outpatients on inotropic therapy awaiting transplant received appropriate therapy from WCD 3
Contraindications (Class III: Harm, Level B-NR)
- Patients requiring bradycardia pacing
- Patients requiring cardiac resynchronization therapy (CRT)
- Patients requiring antitachycardia pacing for VT termination 1
- Patients with unipolar pacemakers (potential fatal device-device interaction) 4
Practical Considerations
- Device should be worn continuously (24 hours/day) except during bathing/showering 2
- Compliance is critical - reported median wear time in studies is 23.1-23.4 hours/day 5, 6
- Regular reassessment of cardiac function is essential to determine if permanent ICD is needed
- First shock efficacy is approximately 99% with 90% post-shock survival in registry data 2
- Inappropriate shock rate is relatively low (0.7-2.8%) 2, 5
Pitfalls and Caveats
- Fatal device-device interactions have been reported between LifeVest and unipolar pacemakers - careful evaluation of existing cardiac devices is essential 4
- Patient adherence is crucial - documented case of sudden cardiac death occurred when patient paused wearing the device 6
- Regular reassessment of LVEF is necessary - in cardiac surgery patients, median LVEF improved from 28% to 35% during follow-up, with 63% avoiding ICD implantation 5
- Proper patient education is essential to ensure correct use and maximize compliance
The LifeVest provides an important bridge therapy for patients at risk of sudden cardiac death who cannot immediately receive an ICD, with the strongest evidence supporting its use after ICD removal in patients with prior sudden cardiac arrest or sustained ventricular arrhythmias.