PROJECT SUMMARY/ABSTRACT MUSIC is an observational cohort study that utilizes routinely collected clinical and cardiac (electrocardiogram [EKG], echocardiogram, cardiac MRI [CMR], exercise testing) data to assess the association between multisystem inflammatory syndrome in children associated with COVID-19 (MIS-C) and cardiac outcomes within the first year after hospital discharge. The objective of the study is to determine the spectrum and time course of coronary artery involvement, left ventricular (LV) systolic function, and arrhythmias or conduction system disturbances within the first year from illness onset, and to define associated clinical and laboratory factors. Approximately 1200 subjects will be enrolled and followed for up to 5 years after initial onset. The Specific Aim of the DCC is to manage the MUSIC study development, launch, data collection and dissemination of results.