Characteristics, Outcomes, and Treatment of Heart Failure With Improved Ejection Fraction

Background Many patients with heart failure (HF) with reduced ejection fraction (HFrEF) experience improvement or recovery of left ventricular ejection fraction (LVEF). Data on clinical characteristics, outcomes, and medical therapy in patients with HF with improved ejection fraction (HFiEF) are scarce. Methods and Results Of 5625 consecutive patients hospitalized for acute HF in the KorAHF (Registry [Prospective Cohort] for Heart Failure in Korea) study, 5103 patients had baseline echocardiography and 2302 patients had follow‐up echocardiography at 12 months. HF phenotypes were defined as persistent HFrEF (LVEF ≤40% at baseline and at 1‐year follow‐up), HFiEF (LVEF ≤40% at baseline and improved up to 40% at 1‐year follow‐up), HF with midrange ejection fraction (LVEF between 40% and <50%), and HF with preserved ejection fraction (LVEF ≥50%). The primary outcome was 4‐year all‐cause mortality from the time of HFiEF diagnosis. Among 1509 HFrEF patients who had echocardiography 1 year after index hospitaliza...