Management of Patients with Low Ejection Fraction Prescribed a Wearable Cardioverter-Defibrillator

Immediate Medical Optimization

• The European Society of Cardiology recommends initiating or uptitrating ACE inhibitors to target doses in all patients with reduced ejection fraction unless contraindicated, as this reduces mortality and prevents progression to symptomatic heart failure 1, 2, 4
• The American College of Cardiology recommends starting evidence-based beta-blockers (bisoprolol, carvedilol, or metoprolol succinate) immediately after stabilization, as these reduce mortality in patients with low ejection fraction 1, 2, 5
• The American Heart Association suggests adding 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 2, 6
• The European Society of Cardiology recommends considering sacubitril/valsartan as replacement for ACE inhibitor in ambulatory patients with heart failure with reduced ejection fraction who remain symptomatic despite optimal medical therapy 1

Device Compliance Monitoring

• The American College of Cardiology recommends targeting 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 1, 2

Reassessment Timeline and ICD Decision

• The European Society of Cardiology recommends proceeding with permanent ICD implantation if ejection fraction remains ≤35% after ≥3 months of optimal medical therapy, patient has NYHA Class II-III symptoms, ischemic cardiomyopathy present (at least 40 days post-MI), non-ischemic dilated cardiomyopathy with persistent low ejection fraction, or expected survival >1 year with good functional status 1, 2, 7, 8, 9

High-Risk Populations Requiring Intensive Monitoring

• The American College of Cardiology recommends most intensive monitoring required in first 40 days post-MI with ejection fraction ≤35%, as ICD implantation is contraindicated during this period 1, 8

Critical Pitfalls to Avoid

• The American Heart Association advises not to rely solely on WCD for monitoring—it is designed primarily for treatment, not continuous surveillance 3
• The European Society of Cardiology recommends not to implant permanent ICD within 40 days of MI, as this does not improve mortality and WCD should bridge this period 1, 8