Which LVEF range defines heart failure with mid-range ejection fraction (HFmrEF)?

• A. EF <40%
• B. EF 40–49%
• C. EF ≥50%
• D. EF 50–60%

Answer: (B)

Left ventricular ejection fraction (EF) is the measure used to categorize heart failure by how well the heart pumps. The group with reduced EF is defined by an EF less than forty percent, while the preserved EF group is defined by an EF of fifty percent or higher. The mid-range category captures EF in the forty to forty-nine percent range. That interval is the best fit for heart failure with mid-range EF because it sits between the two extremes and identifies a distinct clinical picture that isn’t fully reduced or fully preserved. Patients in this range may share features of both categories and can have different responses to therapy and prognosis, which is why this range is used to define HFmrEF. For EF below forty percent you’d think of reduced EF, and for fifty percent or more you’d think of preserved EF.