By: James Pitt  Jul. 06, 2018

Heart failure can be classified by ejection fraction. In heart failure with reduced ejection fraction (HFrEF, aka LVEF), the left ventricle pumps out an unusually low fraction of the blood that enters it. HFrEF has been a focus of research efforts, because most studies find it is associated with higher mortality than heart failure with preserved ejection fraction (HFpEF).