PROBLEM TO BE SOLVED : To provide novel medicines for preventing or treating heart failure, methods for selecting heart failure patients for which treatment with the medicine is effective, and methods for screening drugs to prevent or treat heart failure.SOLUTION : The present invention provides a medicine for preventing or treating heart failure, which comprises an antagonist of adrenocorticotropin-releasing hormone receptor 2 as an active ingredient, and a method comprising of selecting a subject for which the treatment with the above-mentioned medicine is effective, which comprises : measuring an agonist concentration of adrenocorticotropin-releasing hormone receptor 2 in blood of a subject; and selecting a subject whose measured value is higher than the reference value; as well as a method for screening a drug to prevent or treat heart failure which comprises selecting a substance that inhibits the binding of adrenocorticotropin-releasing hormone receptor 2 to its ligand or a substance that inhibits the intracellular signal transduction caused by the binding of adrenocorticotropin-releasing hormone receptor 2 to its ligand.SELECTED DRAWING : NoneCOPYRIGHT : (C)2019, JPO&INPIT