Cardiovascular Radiologic and Metabolic Assessment in HIV: An Investigation of Pathophysiology

Background: \- Antiretroviral therapy has increased the lifespan of people with human immunodeficiency virus (HIV), but recent research suggests that people with HIV also have an increased risk of developing cardiovascular disease. To better understand the prevalence and effects of heart disease in people with HIV, researchers are interested in comparing heart imaging and metabolism studies to see if there are differences between HIV-positive and HIV-negative people. Objectives: \- To study metabolism and heart function in people with HIV compared with healthy HIV-negative volunteers. Eligibility: \- Individuals at least 18 years of age who either have been diagnosed with HIV or are healthy HIV-negative volunteers. Design: * Participants will be evaluated with a physical exam, detailed medical history, and routine blood and urine tests including HIV testing. * Participants will have the following imaging scans: * Cardiac magnetic resonance imaging (MRI) to study the health of the heart and blood vessels * Magnetic resonance spectroscopy (MRS) of the heart, liver, and skeletal muscle * Cardiac computerized tomography (CT) scan to measure calcium levels in the heart and nearby arteries * Dual-energy x-ray absorptiometry (DEXA) scan to measure body fat and muscle mass. * Stable isotope infusion to evaluate how the body processes fat (which will require an overnight stay before the test) * Participants will also have blood tests, an echocardiogram, and an electrocardiogram to evaluate heart function.