Gaurav Gulati, James E. Udelson

Among patients with heart failure with reduced ejection fraction, investigators have repeatedly identified a subgroup whose left ventricular ejection fraction and structural remodeling can improve to normal or nearly normal levels with or without medical therapy. This subgroup of patients with "heart failure with improved ejection fraction" has distinct clinical characteristics and a more favorable prognosis compared with patients who continue to have reduced ejection fraction. However, many of these patients also manifest clinical and biochemical signs of incomplete resolution of heart failure pathophysiology and remain at some risk of adverse outcomes, thus indicating that they may not have completely recovered. Although rigorous evidence on managing these patients is sparse, there are several reasons to recommend continuation of heart failure therapies, including device therapies, to prevent clinical deterioration. Notable exceptions to this recommendation may include patients who recover from peripartum cardiomyopathy, fulminant myocarditis, or stress cardiomyopathy, whose excellent long-term prognoses may imply true myocardial recovery. More research on these patients is needed to better understand the mechanisms that lead to improvement in ejection fraction and to guide their clinical management.