Noun
HFrEF (countable and uncountable, plural HFrEFs)
(medicine, cardiology) Initialism of heart failure with reduced ejection fraction.
Coordinate terms: HFmrEF, HFpEF
HFrEF occurs when the left ventricle (LV) muscle is not able to contract adequately and therefore, expels less oxygen-rich blood in to the body. Source: Internet