Dystrophin associated heart dysfunction is a leading cause of death in patients with Duchenne and Becker Muscular dystrophy (DMD/BMD) and Duchenne and Becker muscular dystrophy carriers (MDC); however, the evolution of heart dysfunction is not well-understood. The central objectives of this proposal are to elucidate this evolution of heart dysfunction and identify measures from cardiac MRI images that can predict death or significant heart disease in patients with DMD/BMD/MDC. This study will create a large clinical and cardiac MRI registry of dystrophin associated heart dysfunction, will utilize advanced image analysis techniques, including deep learning neural networks, to comprehensively evaluate every patient, and will create a risk toolkit accessible to clinicians around the world; this proposal has the potential to improve the quality of life in patients with dystrophin associated heart dysfunction by allowing for earlier and more intensive therapy in patients with severe disease and by identifying surrogate outcome measures for use in therapeutic trials.