Spironolactone Initiation Registry Randomized Interventional Trial in Heart Failure With Preserved Ejection Fraction

Inclusion Criteria: * Written informed consent * Age ≥50 years * Stable heart failure defined by symptoms and signs of heart failure as judged by local Investigator * Left ventricular ejection fraction (LVEF) ≥40% recorded in last 12 months (stratified to max 2/3rd in either 40-49% or ≥50% group) * Elevated natriuretic peptide levels, as defined by any of the following: 1. most recent NT-proBNP \>300 ng/L (or BNP\>100 pg/mL) in sinus rhythm at time of blood sampling; adjustments may be made for BMI according to table 3. 2. most recent NT-proBNP \>750 ng/L (or BNP \>250 pg/mL) in atrial fibrillation at time of blood sampling; adjustments may be made for BMI according to table 3. 3. NT-proBNP \>1200 ng/L (or BNP \>400 pg/mL) within the last 12 months even if most recent value is lower. * Regular use of loop diuretics, defined as daily or most days of the week * NYHA Class II-IV Exclusion Criteria: Previously enrolled in this study * Known Ejection Fraction \< 40% ever * Current absolute indication or contraindication for MRA (mineral receptor antagonist) in judgement of Investigator * Known chronic liver disease * Probable alternative explanations for symptoms: * Known primary cardiomyopathy (hypertrophic, constrictive, restrictive, infiltrative, congenital) * Primary hemodynamically significant valve disease * Right-sided HF not due to left-sided HF * Significant chronic pulmonary disease defined by Investigator or by requirement for home O2 * Symptomatic anemia, defined as Hemoglobin \< 10 g/dL (100 g/L ) * Heart transplant or LVAD (left ventricular assist device) recipient * Presence of cardiac resynchronization therapy (CRT) device * Systolic blood pressure \<90 or \>160 mmHg * K (potassium) \>5.0 mmol/L * eGFR (estimated glomerular filtration rate) by MDRD (Modification of Diet in Renal Disease) \< 30 ml/min/1.73m2 or creatinine \> 2.5 mg/dL (221 µmol/L ) * Current lithium use * Current dialysis * Actual or potential for pregnancy * Participation in another interventional clinical trial where a mineralocorticoid receptor antagonist is studied * Any condition that in the opinion of the Investigator may interfere with adherence to trial protocol