1. From the Department of Cardiology, Hospital of the Government of the City of Buenos Aires "Dr. Cosme Argerich" (T.F.C., M.C.S.) and Cardiovascular MR Unit, TCba Cardiology Department (M.J.M., M.F.R.), Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina; and Department of Cardiology, Sanatorio Pasteur, San Fernando del Valle de Catamarca, Catamarca, Argentina (J.F.V., M.P.M.).