1. From the Departments of Cardiothoracic Surgery (K.M.J.C., P.P.P., G.D.D., J.R.P.), Cardiology (M.F., I.R., S.R.H.), Cardiovascular Magnetic Resonance (K.M.J.C., R.W., K.S., D.J.P., P.J.K.), and the Clinical Trials and Evaluation Unit (K.M.J.C., M.F., J.R.P.), Imperial College London, London, United Kingdom (K.M.J.C., P.P.P., D.J.P., P.J.K., G.D.D., J.R.P.); Royal Brompton and Harefield National Health Service Foundation Trust, London, United Kingdom (K.M.J.C., M.F., R.W., K.S., I.R., S.R.-H., D.J.P....