Body Composition Ultrasound for Patients With Heart Failure

The investigators will be recruiting both healthy subjects without HF, as well as subjects with either HF, a left ventricular assist device (LVAD) or cardiac transplantation. This is an observational study to validate the use of the BodyMetrix BX 2000 Pro ultrasound machine for the assessment of body composition, particularly muscle wasting. The ultrasound device received 501(k) designation from the FDA in 2009 for measurement of localized fat and muscle thickness. Participation will last for only one day, with approximately 2 hours of study activity in total: 1. For woman with child-bearing potential, potential participants will be required to undergo a urine pregnancy test prior to DXA imaging. 2. The investigators will record participant age, sex, height, weight and heart failure status. 3. Muscle ultrasound: investigators will make measurements at 7 positions on the arm, chest wall, and leg (participant's dominant side). Clear ultrasound gel will be applied to the skin, a BodyMetrix ultrasound probe placed against the skin, and the muscle thickness measurement made five times at each position. The gel is then wiped away. 4. Whole body dual X-ray absorptiometry (DXA) scan: the DXA scan involves lying on a flat and open scanner for approximately 5 minutes while an X-ray arm passes over the body to form a picture for whole body composition. 5. Handgrip strength: this involves the participant squeezing a handheld machine on three occasions in the dominant hand to measure grip strength. 6. 5 sit-to-stand test: investigators will time how long it takes for the participant to stand up from a seated position five times to assess lower body strength.