Pilot Study on Withdrawal of Spironolactone Among Heart Failure With Improved Ejection Fraction

Inclusion Criteria: * Willing and capable of providing informed consent and agrees to follow the study protocol and schedule of clinical follow-up * Age between 19 and 80 years old * Prior diagnosis of heart failure with reduced left ventricular ejection fraction (LV EF ≤ 35%) and on medical therapy including spironolactone combined with angiotensin-converting enzyme or angiotensin receptor blocker or antiotensin receptior neprilysin blocker, beta-blocker. * LV EF ≥ 50% documented with echocardiography performed within a month * Documented result of BNP or NT-proBNP level within a month Exclusion Criteria: * Dyspnea ≥ New York Heart Association (NYHA) functional class III * Patients who need to discontinue spironolactone owing to prior adverse event * Primary valvular heart disease with at least moderate degree * Estimated glomerular filtration rate less than 30 mL/min per 1.73 m2 * Uncontrolled hypertension defined as blood pressure more than 140/90 mmHg * Presence of other clinical reason to continue spironolactone such as myocardial infarction, primary aldosteronism, and liver cirrhosis * Hyperkalemia defined as serum potassium level less than 3.5 mmol per liter * Pregnant and/or lactating women * Life expectancy less than a year * Patients who are not suitable to enrollment by investigator's discretion