Exogenous KETOne Supplements in Patients Hospitalized for Acute Heart Failure

The study will enroll adult patients (≥18 years) admitted with AHF as the primary diagnosis, meeting all the following criteria:

1. Documented new or worsening symptoms due to heart failure with at least one of thefollowing: persistent dyspnea at rest or with minimal exertion, or fatigue.

2. Objective evidence of worsening heart failure, consisting of at least two physicalexamination findings consistent with fluid retention and/or end-organ hypoperfusionor one physical examination finding and at least one laboratory criterion: a) Physical examination findings considered to be due to heart failure, includingnew or worsened: i. Peripheral edema ii. Increasing abdominal distention or ascites (in the absence of primary hepatic disease) iii. Pulmonaryrales/crackles/crepitations iv. Increased jugular venous pressure and/orhepatojugular reflux v. S3 gallop vi. Clinically significant or rapid weight gainthought to be related to fluid retention b) Laboratory evidence of worsening HF, ifobtained within 24 hours of presentation, including: i. Increased B-type natriureticpeptide (BNP) / N-terminal pro-BNP (NT-proBNP) concentrations consistent withdecompensation of heart failure. In patients with chronically elevated natriureticpeptides, an increase of >30% above baseline should be noted. ii. Radiological evidence of pulmonary congestion iii. Echocardiographic criteriainclude: Dilated inferior vena cava with minimal collapse on inspiration; decreasedleft ventricular outflow tract (LVOT) minute stroke distance (velocity time integral [VTI]); septal or lateral E/e' >15 or >12, respectively; D-dominant pulmonaryvenous inflow pattern. iv. Invasive diagnostic evidence with right heart catheterization showing apulmonary capillary wedge pressure ≥18 mmHg, central venous pressure ≥12 mmHg, or acardiac index <2.2 L/min/m2

3. Treatment with at least 40 mg of intravenous furosemide or its equivalent and/orintravenous vasoactive drugs and/or inotropic drugs.

4. An LVEF of ≤35% is required, measured during the present hospitalization.

5. Participants must present with elevated levels of natriuretic peptides, specificallyNT-proBNP ≥600 pg/mL or BNP ≥150 pg/mL. For those in atrial fibrillation at the timeof inclusion, NT-proBNP levels must be ≥900 pg/mL or BNP ≥225 pg/mL.

The enrollment window extends to the first five days of the hospital stay.

Exclusion Criteria:

1. Current hospitalization for AHF triggered by significant arrhythmia (atrialfibrillation/flutter with sustained ventricular response >110 beats per minute,clinically significant bradycardia, or sustained ventricular tachycardia)

2. Cardiogenic shock in INTERMACS level 1 or 2 (i.e. unstable hemodynamics despiteinotropic/vasopressor therapy)

3. Likelihood or current use of mechanical circulatory support

4. Recent cardiac surgery within 3 days

5. Ongoing severe infection or sepsis, severe anemia, acute exacerbation of chronicobstructive pulmonary disease, pulmonary embolism, or cerebrovascular accident

6. Significant primary valvular disease (hemodynamically severe uncorrected primarycardiac valvular disease)

7. Planned implantation of a cardiac resynchronization therapy device

8. eGFR <15 mL/min/1.73 m2 during current hospitalization (unless ongoing continuousrenal replacement therapy) or recurring dialysis

9. Known obstructive hypertrophic cardiomyopathy, congenital heart disease, acutemechanical cause of acute heart failure (e.g., papillary muscular rupture), acutemyocarditis, or constrictive pericarditis according to the treating physician

10. Type 1 diabetes

11. Advanced liver disease (Child-Pugh class C)

12. Dementia or other cognitive disorder making the patient unable to give informedconsent

13. Pregnancy or breastfeeding

14. Inability to intake oral substances or severe dysphagia

15. Significant gastrointestinal disease (i.e. severe inflammatory bowel disease orgastric ulcer)

16. Adherent to a ketogenic diet within 30 days of enrollment

17. Awaiting cardiac transplantation

18. Very severe lung disease and/or treatment with continuous home oxygen therapy

19. Major comorbidity, medical condition, or health issue that, according to theinvestigator's judgment, would hinder the participant's capacity to engage in orsuccessfully finish the study