1. From the Division of Cardiovascular Diseases, Mayo Clinic and Foundation, Rochester, Minn (C.S.P.L., V.L.R., R.J.R., B.A.B., S.R.O., M.M.R.); Yong Loo Lin School of Medicine, National University of Singapore, Singapore (C.S.P.L.); Department of Cardiology, University Policlinico Hospital, Modena, Italy (F.B.); and Division of Cardiology, Department of Medicine, Johns Hopkins Medical Institutions, Baltimore, Md (D.A.K.).