1. From the Department of Medicine (W.Y.K., M.S., W.J.M, R.M.B.), Cardiovascular Division, and the Department of Radiology (W.J.M.), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Mass; The MR-Center, Department of Cardiology (W.Y.K.) and Institute of Experimental Clinical Research, Aarhus University Hospital, Skejby Sygehus, Denmark; Philips Medical Systems (M.S., R.M.B.), Best, the Netherlands; and Philips Research Laboratories (P.B.), Hamburg, Germany.