1. From the Department of Cardiology (S.B., J.D.), Carcinoid Heart Disease Clinic, Royal Free Hospital, London, United Kingdom; Neuroendocrine Tumour Unit (C.T., M.C.), Royal Free Hospital, London, United Kingdom; the Department of Pathology (M.B.), Harefield Hospital, Harefield, Middlesex, United Kingdom; and Centre for Cardiovascular MR (A.M.T.), UCL Institute of Child Health and Great, Ormond Street Hospital for Children, London, United Kingdom.