1. From the Department of Cardiology (A.S.F., J.C.M.), The Heart Hospital, Part of University College London Hospitals NHS Trust, London; the Department of Medicine (A.S.F., J.C.M.), University College London; and the Department of Cardiology (M.A.W., L.C.D., A.M.), The London Chest Hospital, Bonner Road, London, United Kingdom.