Exercise Intolerance in Heart Failure

This research is being done to better understand why patients with heart failure have
difficulty exercising and performing some activities of daily living. Heart muscle and
skeletal muscle (in the legs and arms) depend on normal metabolism (the conversion of foods
to chemical fuel) to function properly. Investigators will measure metabolites in the heart
and leg muscles, including the levels of high energy phosphates and lipids (fats) using
magnetic resonance (MR) techniques. High-energy phosphates serve as a source of energy, which
is used by the heart and skeletal muscle for contraction. Magnetic resonance uses magnetic
fields to measure the levels of these substances.

Inclusion Criteria:

- Patients of either gender who are greater than 21 years of age (no upper age limit),

- Permission of patient's clinical attending physician,

- Previous clinical diagnosis of HF with current New York Heart Association (NYHA) Class
II-III symptoms for at least 1 month,

- Left ventricular ejection fraction (EF) >50% by echocardiography, MRI, CT or x-ray or
nuclear ventriculography within prior 12 months,

- Stable medical therapy for at least 30 days (no addition or removal or major (>100%)
dose change of Renin-Angiotensin-Aldosterone System (RAAS) antagonists, beta-blockers,
or calcium channel blockers for hypertension).

Exclusion Criteria:

- Unable to understand the risks, benefits, and alternatives of participation and give
meaningful consent,

- Contraindications to MRI such as implanted metallic objects (pre-existing cardiac
pacemakers, cerebral clips) or indwelling metallic projectiles,

- Significant valvular abnormalities,

- Pregnant women (women of childbearing potential will undergo blood or urine pregnancy
testing),

- History of coronary artery disease (CAD) requiring revascularization (PTCA or coronary
bypass surgery), positive exercise tolerance test (ECG changes diagnostic for ischemia
or stress-induced perfusion defect), or significant epicardial coronary disease (>50%
stenosis) in major coronary artery by x-ray or CT angiography,

- History of infiltrative cardiomyopathy or constrictive pericarditis,

- Cor pulmonale,

- Significant pulmonary disease,

- Estimated glomerular filtration rate (eGFR) <20ml/min,

- Any condition other than HF which could limit the ability to perform a 6MW or
cardiopulmonary exercise test (CPET) test (e.g., critical peripheral vascular disease,
significant orthopedic or neurological conditions),

- Any diseases other than HF which are likely to significantly alter the patient's
global perception of status or quality of life over a period of 6 months.

- Significant peripheral vascular disease