When is an ICD recommended in HF?

• A. In all HF patients regardless of EF.
• B. In HFrEF patients who are at risk of sudden cardiac death, typically EF ≤35% after GDMT optimization, depending on guideline.
• C. Only in HFpEF.
• D. Never in HF.

Answer: (B)

The main idea is that an implantable cardioverter-defibrillator (ICD) is used for primary prevention of sudden cardiac death in people with heart failure who remain at high risk after optimizing medical therapy. The key signal is a persistently reduced ejection fraction, which identifies those at greatest risk of malignant ventricular arrhythmias.

In current practice, an ICD is recommended for patients with heart failure with reduced ejection fraction who have not achieved full risk reduction with guideline-directed medical therapy. If their EF is 35% or lower after optimizing therapy (and other favorable factors are present), an ICD is considered appropriate to help prevent sudden death. Guidelines often specify a waiting period—typically a few months of optimized therapy—to confirm that the reduced EF is persistent before proceeding with ICD implantation, and the decision also depends on overall prognosis and comorbidities.

Why the other statements don’t fit: ICDs are not routinely recommended for all heart failure patients regardless of EF, because patients with preserved EF (HFpEF) generally do not derive the same survival benefit from ICDs. They are also not appropriate “never” in heart failure, since eligible patients with HFrEF and persistent low EF after GDMT have clear rationale for ICD therapy. And they are not exclusive to HFpEF, which makes that option incorrect.