Which EF cutoffs define HFrEF, HFpEF, and HFmrEF?

• A. HFrEF EF <35%; HFpEF EF ≥60%; HFmrEF EF 35-49%
• B. HFrEF EF <50%; HFpEF EF ≥60%; HFmrEF EF 40-49%
• C. HFrEF EF <40%; HFpEF EF ≥50%; HFmrEF EF 41-49%
• D. HFrEF EF <30%; HFpEF EF ≥50%; HFmrEF EF 30-40%

Answer: (C)

Ejection fraction (EF) is the measure used to separate heart failure into three phenotypes based on how well the left ventricle pumps blood each beat. Normal EF is roughly 50-70%. When EF drops, it points to systolic dysfunction and heart failure can be categorized by how low the EF is.

HFrEF is defined by a reduced pumping ability, typically EF below 40%. HFmrEF sits in the middle, with EF in the mid-range (about 40-49% in many guidelines). HFpEF represents preserved pumping function, with EF 50% or higher. This stratification helps guide treatment decisions and prognosis because patients with lower EF often respond differently to therapies than those with preserved EF.

So the option that states HFrEF as EF under 40%, HFmrEF as EF in the mid-range (41-49%), and HFpEF as EF 50% or higher aligns with how the EF spectrum is used to define these categories. Other cutoffs that widen or narrow these ranges can leave portions of the spectrum unclassified or misaligned with standard practice.