Heart Failure (HF) is a major public health issue because the disease affects 1-2% of the Western population and the lifetime risk of HF is 20%. Despite major improvements in the management and care of patients with HF, the 1-year mortality in patients with HF is 13% and >50% of HF patients are admitted during a 2.5 year period. Furthermore, patients with HF have markedly decreased physical capacity and quality of life. Thus, there is a need for new treatment modalities in this group of patients.

It is well established that patients with heart failure have metabolic disturbances, including disturbed glucose metabolism with increasing insulin resistance, increased lipolysis, and disturbances in skeletal muscle homeostasis.

Presently there are no data on the clinical metabolic effects of long-term oral ketone-supplementation in patients with chronic HF.

In this study we aim to investigate the effect of 14 days modulation of circulating ketone body levels on endogenous protein, glucose, and fatty acid metabolism in patients with HFrEF.

Inclusion Criteria:

• Chronic heart failure with NYHA II-III
• Left ventricular ejection fraction ≤40%
• Negative urine-HCG for women with childbearing potential

Exclusion Criteria:

• Known diabetes or HbA1c ≥48 mmol/mol
• Significant cardiac valve disease
• Severe stable angina pectoris
• Age <18 years