A SkeleTal Muscle Recovery Intervention With Dietary Protein in Heart Failure

Inclusion Criteria: 1. Left ventricular ejection fraction (LVEF) ≤40%, New York Heart Association (NHYA) class II to IV symptoms or N-terminal pro B-natriuretic peptide (NT-proBNP) \>300 pg/mL 2. Age 18 years to 100 years, inclusive 3. Receiving guideline-directed medical therapy (GDMT), unless contraindicated or not tolerated 4. Any of the following markers of severe HF within prior 12 months: i) Inotropic therapy; ii) 1 or more HF hospitalizations; iii) LVEF ≤25%; iv) Peak oxygen consumption (VO2) \<50% predicted or ≤16 mL/kg/min; v) 6-minute walk distance \<300 meters; vi) Unintentional weight loss \>5% of bodyweight over the past year; vii) Moderate or severe muscle wasting on physical examination; viii) NT-proBNP ≥900 pg/mL Exclusion Criteria: 1. Pregnancy, planning to become pregnant, or women of reproductive potential unwilling to complete pre-DXA urine pregnancy test before first DXA or randomization 2. History of left ventricular assist device (LVAD), heart transplantation, or estimated glomerular filtration rate (eGFR) \<20 mL/min/1.73 m2 3. An identified clinical disorder associated with skeletal muscle weakness/wasting (e.g., muscular dystrophy, mitochondrial disorder, active cancer, modified Rankin score greater or equal to 4 post-stroke) 4. Milk allergy, protein allergy, lactose intolerance, and galactosemia 5. Weight ≥350 pounds and/or BMI ≥40 kg/m2 6. Initiation of obesity-dosed GLP-1 or GIP/GLP-1 agonist within 3 months prior to screening, or clinical intention to begin such an anti-obesity medication within the next 6 months.