1. From the Imperial Centre for Translational and Experimental Medicine, Myocardial Function Section, Imperial College London and Imperial College NHS Trust, London, United Kingdom (P.S.D., P.K., R.C., N.S.P.); Department of Medicine, Whittington Hospital, London, United Kingdom (R.G.); and Faculty of Health and Medical Sciences, Institute of Biosciences and Medicine, University of Surrey, Guildford, United Kingdom (R.J., C.H.F.).