EMPA Acute Heart Failure

Inclusion Criteria: 1. Age ≥ 18 years 2. Patients with acute heart failure with associated signs or symptoms (dyspnea on exertion, orthopnea, paroxysmal dyspnea, peripheral oedema, chest x-ray with pulmonary congestion) 3. Serum levels of NT-proBNP ≥ 1000 pg/ml within 48 hours of Informed Consent 4. Written informed consent prior to study participation Exclusion Criteria: 1. Type 1 diabetes 2. Participants of child-bearing age without adequate contraception 3. Pregnancy or lactating females 4. Cardiogenic shock 5. Acute coronary syndrome within 30 days prior to randomization 6. Planned or recent percutaneous or surgical coronary intervention within 30 days prior to randomization 7. Signs of ketoacidosis and/or hyperosmolar hyperglycemic syndrome (pH ≤ 7.30 and glucose \>14 mmol/l and HCO3- ≤ 18 mmol/l) 8. Signs of uncontrolled active infection 9. Dyspnea due to non-cardiac causes (severe pulmonary disease, anemia, severe obesity), non-HF causes such as acute or chronic respiratory disorders 10. Coronary artery disease with requirement for revascularization within the study period 11. Renal impairment (GFR \< 20 ml/min/1,73 m2) 12. Known hepatic impairment (as evidenced by total bilirubin \>3 mg/dL) or history of cirrhosis with evidence of portal hypertension (e.g., presence of esophageal varices) 13. Uncontrolled thyroid disease 14. Endocrinopathies like Graves' disease, acromegaly, Cushings' disease 15. Hypertensive retinopathy or encephalopathy 16. Bariatric surgery in last 2 years prior to randomization 17. Patients in whom study participation is not deemed appropriate under consideration of clinical wellbeing by the principal investigator 18. The subject is mentally or legally incapacitated 19. The subject received an investigational drug within 30 days prior to inclusion into this study 20. Urinary tract infections or significant formation of residual urine in medical history 21. Patients with particular risk for ketoacidosis (alcohol abuse, pancreatitis, pancreatic insulin deficiency from any cause, caloric restriction etc.) or ketoacidosis in the past 22. Frequent hypoglycaemic events (in the opinion of the investigator) 23. Intolerance to Empagliflozin and excipients in Empagliflozin or rather placebo 24. Patients with severe stenosis or regurgitation of the aortic, pulmonary or mitral valve