Which EF threshold is typically considered for ICD consideration after GDMT optimization?

• A. EF ≥50%
• B. EF ≤25%
• C. EF ≤35% after GDMT optimization
• D. EF any value if symptomatic

Answer: (C)

In this scenario, the main idea is that the decision for an implantable cardioverter-defibrillator (ICD) for primary prevention hinges on the left ventricular ejection fraction after optimizing heart failure therapy. After GDMT optimization, an EF of 35% or lower identifies patients at elevated risk of sudden cardiac death who stand to benefit from ICD therapy. This threshold is supported by trials showing mortality benefit from ICDs in patients with reduced EF who remain on guideline-directed medical therapy. If EF improves to above 35% with optimization, the justification for ICD becomes much weaker, and the device may not be indicated. Symptoms alone do not determine ICD candidacy; the EF value after optimizing therapy is the key risk marker.