1. From the Heart Hospital, University College London Hospitals NHS Trust (C.J.C., G.Q., A.S.F., A.A.P., W.J.McK., J.C.M.), the Department of Medicine, University College London (C.J.C., A.S.F., W.J.McK., J.C.M.), London, UK; and the Department of Cardiology, S. Andrea Hospital, University “La Sapienza,” Rome, Italy (G.Q.).