This study is being done to see how well a device called FibroScan can detect high pressure in the large vein that carries blood to the heart. FibroScan is a quick, painless test that measures how stiff the liver is, and researchers want to know if those measurements can help identify people with elevated central venous pressure. You are being asked to participate because you have been suspected of having, or diagnosed with, heart failure. Everyone in the study will have the same tests, which include a FibroScan exam, heart ultrasound, EKG, blood work, and a right-heart catheterization. The study lasts about one week and includes a screening visit, a baseline visit, and a phone check-in. By taking part, you may help researchers learn whether this noninvasive device can provide useful information about heart function. Participation is completely voluntary, and choosing not to join will not affect your medical care.

Patients with end stage heart failure (HF) exhibit abnormalities in their skeletal muscle, thought to be as a result of reduced blood flow to the muscle as their HF worsens. We will identify the relative nature of these changes by obtaining skeletal muscle biopsies in HF patients as well as healthy control subjects without HF. These biopsies will be from the right upper thigh as well as from the right calf muscle. We will compare these biopsies to identify if the changes we are seeing are in fact more severe in the calf compared to the thigh muscle.