RecruitingMagnetic Resonance Spectroscopy Studies of Cardiac Muscle MetabolismThe metabolism of the heart provides the chemical energy needed to fuel ongoing normal heart contraction. Magnetic resonance spectroscopy is a technique used in a MRI scanner that can be used to measure and study heart metabolism directly but without blood sampling or obtaining tissue biopsies. One of the hypotheses this study aims to investigate is whether energy metabolism is reduced in heart failure and whether that contributes to the poor heart function.