What is the management plan for a patient with low Ejection Fraction (EF) who has been prescribed a life vest?

Management of Patients with Low Ejection Fraction Prescribed a Wearable Cardioverter-Defibrillator (Life Vest)

Patients with low EF prescribed a wearable cardioverter-defibrillator require optimization of guideline-directed medical therapy, strict monitoring of device compliance (targeting >23 hours/day wear time), and reassessment of LVEF after 3 months to determine need for permanent ICD implantation. 1, 2

Immediate Medical Optimization

Pharmacological Management

• Initiate or uptitrate ACE inhibitors to target doses in all patients with reduced EF unless contraindicated, as this reduces mortality and prevents progression to symptomatic heart failure 1
• Start evidence-based beta-blockers (bisoprolol, carvedilol, or metoprolol succinate) immediately after stabilization, as these reduce mortality in patients with low EF 1
• Add mineralocorticoid receptor antagonist (spironolactone or eplerenone) for patients remaining symptomatic despite ACE inhibitor and beta-blocker therapy, monitoring potassium <5.0 mEq/L and creatinine ≤2.5 mg/dL in men or ≤2.0 mg/dL in women 1
• Consider sacubitril/valsartan as replacement for ACE inhibitor in ambulatory patients with HFrEF who remain symptomatic despite optimal medical therapy 1

Diuretic Management

• Prescribe loop diuretics for any evidence of fluid retention to improve symptoms and exercise capacity 1
• Monitor urine output, renal function, and electrolytes regularly during diuretic therapy 1

Device Compliance Monitoring

Daily Wear Time Tracking

• Target minimum 23 hours per day of device wear, as the VEST trial demonstrated that only 12 of 48 patients who died were wearing the device at time of death 2
• Document daily wear time through device data downloads 2
• Address barriers to compliance immediately when wear time falls below 21 hours/day 2, 3

Device Functionality Checks

• Verify proper electrode pad contact with skin at each patient encounter to ensure effective shock delivery 2
• Ensure monitor/defibrillator unit remains properly charged and operational 2
• Remove any transdermal medication patches from areas where defibrillator pads are placed to prevent electrical arcing 2

Cardiac Monitoring Parameters

Arrhythmia Surveillance

• Track all recorded ventricular arrhythmias, particularly ventricular fibrillation and pulseless ventricular tachycardia, which are the primary targets for WCD therapy 2, 4
• Document any shocks delivered by the device, including rhythm before and after shock 2
• Record symptoms occurring during arrhythmia episodes 2
• Note that 93.2% of ventricular tachycardia episodes occur within the first 3 months after cardiac surgery or acute events 3

Clinical Status Assessment

• Monitor for worsening heart failure symptoms, particularly in patients with LVEF ≤35% 2
• Assess for cardiac ischemia symptoms, as sudden cardiac death risk peaks early after myocardial infarction 2
• Check electrolyte levels regularly, especially potassium and magnesium, as imbalances trigger arrhythmias 2
• Verify medication compliance with beta-blockers and antiarrhythmic therapy 2

Reassessment Timeline and ICD Decision

Three-Month LVEF Reevaluation

• Repeat echocardiography at 3 months (or earlier if clinical improvement occurs) to reassess LVEF, as 41.5% of patients show significant improvement 4, 3
• Proceed with permanent ICD implantation if:
  • LVEF remains ≤35% after ≥3 months of optimal medical therapy 1
  • Patient has NYHA Class II-III symptoms 1
  • Ischemic cardiomyopathy present (at least 40 days post-MI) 1
  • Non-ischemic dilated cardiomyopathy with persistent low EF 1
  • Expected survival >1 year with good functional status 1

Discontinuation Criteria

• Stop WCD and defer ICD if LVEF improves to >35% with optimal medical therapy 4, 3
• Continue medical optimization without device if patient develops life expectancy <1 year due to non-cardiac causes 5

High-Risk Populations Requiring Intensive Monitoring

Post-Myocardial Infarction Patients

• Most intensive monitoring required in first 40 days post-MI with LVEF ≤35%, as ICD implantation is contraindicated during this period 1
• WCD serves as bridge during this high-risk window 2, 3

Myocarditis Patients

• Calculate necessary wearing time of 86.41 days for myocarditis patients versus 6.46 years for dilated cardiomyopathy, indicating higher early arrhythmia risk in myocarditis 6
• Monitor for ventricular tachycardia occurrence, which is more frequent in acute inflammatory states 6

Cardiac Surgery Patients

• Expect high compliance despite sternotomy (median 23.4 hours/day wear time achieved) 3
• Monitor intensively for first 3 months when 93.2% of arrhythmic events occur 3

Critical Pitfalls to Avoid

• Do not rely solely on WCD for monitoring—it is designed primarily for treatment, not continuous surveillance 2
• Do not implant permanent ICD within 40 days of MI, as this does not improve mortality and WCD should bridge this period 1
• Do not assume WCD substitutes for seeking medical attention when patients experience cardiac symptoms 2
• Do not continue WCD indefinitely—reassess at 3 months maximum, as 37% of patients (excluding ICD explant cases) ultimately require permanent ICD while others improve 4, 3
• Avoid inadequate shock rate by ensuring proper pad placement and skin contact (inadequate shock rate only 0.7% with proper use) 3

Post-Shock Protocol

When WCD delivers a shock:

• Perform immediate assessment including vital signs, 12-lead ECG, and symptom evaluation 2
• Document rhythm strips before and after shock delivery 2
• Verify proper pad placement and skin contact 2
• Consider hospitalization for evaluation of underlying trigger and medication adjustment 2