Ketone and Hawthorn Extract Supplementation in Congestive Heart Failure

Inclusion Criteria: * Equal to or greater than 18 years of age * Diagnosis of heart failure and be classified as NYHA Class II or III either pre-enrollment or at the time of enrollment: Class II - Patients with cardiac disease resulting in slight limitation of physical activity who are comfortable at rest. Ordinary physical activity results in fatigue, palpitation, or dyspnea (shortness of breath or difficulty breathing). Class III - Patients with cardiac disease resulting in marked limitation of physical activity. They are comfortable at rest. Less than ordinary activity causes fatigue, palpitation, or dyspnea (shortness of breath or difficulty breathing). * Stable guideline directed medical therapy for at least 1 month prior to enrollment, including no changes in maintenance diuretic dosing * Taking appropriate guideline directed medical therapy as determined by the investigator, who is a heart failure specialist. Exclusion Criteria * Patients with Type I DM * No metal in the body that would prevent undergoing an MRI scan. This includes pacemakers, stents and non-titanium implants that would be contraindicated for an MRI. * Atrial fibrillation * Inability to exercise on a treadmill. * Moderate or greater valvular disease: a condition where the valves of the heart do not function properly. * Anemia with Hemoglobin \<10 g/dL. * Daily insulin use * Hypertrophic, infiltrative, or inflammatory cardiomyopathy (a group of heart muscle diseases where the heart muscle becomes abnormally thickened (hypertrophic), invaded by abnormal substances (infiltrative), or inflamed (inflammatory), which can lead to impaired heart function and potential complications like arrhythmias and heart failure. * Pericardial disease: a general term for conditions that affect the pericardium, the sac that surrounds the heart. Pericardial diseases include pericarditis, pericardial effusion, cardiac tamponade, and constrictive pericarditis.. * Current angina due to clinically significant obstructive epicardial coronary disease. a condition where the major coronary arteries on the surface of the heart (epicardial arteries) become significantly narrowed due to plaque buildup, restricting blood flow to the heart muscle, often causing chest pain and potentially leading to a heart attack. * Acute coronary syndrome (ACS) refers to a group of conditions where blood flow to the heart is suddenly reduced, causing chest pain or discomfort. * Coronary intervention within the past 2 months is a medical procedure used to treat ACS by opening a blocked coronary artery, typically done through a minimally invasive technique called percutaneous coronary intervention (PCI). * Primary pulmonary arteriopathy is also known as pulmonary arterial hypertension (PAH) or primary pulmonary hypertension (PPH), a rare disorder that causes high blood pressure in the pulmonary arteries. * Known clinically significant lung disease defined as: 1. Current use of supplemental oxygen, aside from nocturnal O2 for the treatment of obstructive sleep apnea 2. The use of steroids/antibiotics within the past 6 months for an acute exacerbation of obstructive pulmonary disease 3. Proximal pulmonary function test (PFT) indicating severe obstructive disease, defined as an FEV1\<50% predicted in the context of an FEV1/FVC ratio of \<0.70 ("Stage III COPD according to GOLD Criteria: significantly reduced lung function and often accompanied by noticeable symptoms like increased breathlessness, frequent exacerbations, and reduced exercise capacity). (note: only to be used if the subject had PFTs prior to screening) 4. Proximal 6-minute walk test during which the subject experienced desaturation (\<94%) without subsequent normal study. * Ischemia on stress testing without subsequent revascularization or left heart catheterization showing non-obstructive epicardial coronary disease. * Significant liver diseases impact on synthetic function or volume control. * Uncontrolled hypertension: BP \>180/110 at baseline. * Estimated glomerular filtration rate (eGFR) eGFR \<30 mL/min/173m2 indicating reduced kidney function * Creatinine level of Cr \>2.5 (2.5 mg/dL) is an indicator of stage 2 chronic kidney disease (CKD). * Current Alcohol dependence * Current substance use disorder. * Chronic narcotic use that cannot be interrupted * Pregnant or lactating females * Subject has a medical, mental or psychiatric disorder or physical condition that could reasonably be expected to interfere with the assessment of cardiac symptoms, or with any of the study assessments or study procedures including the PET-MRI imaging, VO2 Max, Echocardiogram ultrasound, blood samples that would put the study participant at great risk.