1. From Swansea University Medical School, UK (J.P.J.H., K.W., M.B.G.); Swansea University College of Health and Human Sciences, UK (C.P., A.C.); Princess of Wales Hospital, Cardiology, Bridgend, UK (M.G.); and Regional Cardiac Centre, Morriston Hospital, Swansea, UK (J.P.B.).