1. From Medicina Interna II, Ospedale L. Sacco, Università degli Studi di Milano, Milano, Italy (R.F., A.R., L.P.); IRCCS S. Matteo, Universita’ di Pavia, Pavia, Italy (C.P., L.B.); Autonomic Dysfunction Center (A.D., L.D., I.B., D.R.) and General Clinical Research Center (P.A.H.), Department of Biomedical Engineering, Vanderbilt University, Nashville, Tenn; and the Department of Cardiovascular Medicine, John Radcliffe Hospital, Oxford, UK (P.S.).