Changes in Skeletal Muscle Thickness in Patients With Acute Heart Failure

The investigators will be recruiting subjects with advanced cardiomyopathy in cardiogenic shock in the inpatient setting. This is an observational study to better understand changes in lean body mass during critical illness through a quick, safe, and non-invasive method. This study will also validate the use of the BodyMetrix BX 2000 Pro ultrasound machine for the assessment of body composition, particularly muscle wasting, in the cardiogenic shock population.

The ultrasound device received 501(k) designation from the FDA in 2009 for measurement of localized fat and muscle thickness. Baseline US muscle thickness assessments will occur at baseline after consent; then days 3 and 7 after baseline study visit; then every 7 days thereafter until end of the index hospitalization (discharge or death). Each measurement session will take about 20-30 minutes.The investigators will take measurements at two sites: the lateral thigh and bicep (participant's dominant side). Clear ultrasound gel will be applied to the skin and the ultrasound probe placed against the skin, and the muscle thickness measurement made five times at each position.

The US images are read after a study visit completion, with measurements taken at pre-specified anatomic landmarks to obtain the muscle thickness, which is averaged accross the duplicate measurements. The primary endpoints are: Percentage change in skeletal muscle thickness from admission to nadir; Percentage change in skeletal muscle thickness after advanced therapies; and the Relationship between muscle mass loss during cardiogenic shock and subsequent clinical outcomes.