1. From the Divisions of Cardiovascular Diseases (H.I.M., V.T.N., P.A.P., M.E.-S.) and Cardiothoracic Surgery (T.M.S.), Mayo Clinic, Rochester, Minn; Centre Hospitalier Pierre Le Gardeur, Lachenaie, Quebec, Canada (V.A.D.); La Timone Hospital, Marseille, France (J.-F.A.); University Hospital of Bologna, Bologna, Italy (A.R.); and Division of Cardiovascular Diseases, Mayo Clinic, Scottsdale, Ariz (A.J.T.).