1. From the Cardiac MR Research Group (V.M., A.M.T., S.R.H., R.J., R.R.), Division of Imaging Sciences, King’s College London, and Department of Congenital Heart Disease (R.T., J.M.S., S.Q., E.R., E.B., D.A., R.R.), Guy’s Hospital, London, United Kingdom; and Cardiothoracic Unit (A.M.T.), Institute of Child Health and Great Ormond Street Hospital for Children, London, United Kingdom.