1. From the Institute of Cardiovascular Medicine and Science, London, United Kingdom (M.E., R.S., I.K.); Liverpool Heart and Chest Hospital NHS Foundation Trust, United Kingdom (M.E., R.S., I.K.); Wessex Cardiothoracic Centre, University Hospital Southampton NHS Foundation Trust, United Kingdom (Z.N., N.C.); and Faculty of Medicine, University of Southampton, United Kingdom (N.C.).