RecruitingSarcopenia Magnetic Resonance Imaging Evaluation (SUSIE)The goal of the proposed research is to investigate Magnetic Resonance (MR) Fingerprinting and P-MRS (Phosphorus-31 MR Spectroscopy) imaging for characterization of skeletal muscle in heart failure patients with sarcopenia. Heart failure patients with and without sarcopenia will be scanned using MR Fingerprinting and an existing Post-exercise phosphocreatine (PCr) recovery MR imaging protocol to obtain characteristic profiles of quantitative T1, T2, and PCr recovery rate.