1. Cardiovascular Division, Department of Medicine (P.S.V., K.-H.A.C., F.K., P.S.N., O.O., C.S.), University of Minnesota Medical School, Minneapolis, MN.
2. Department of Medicine (C.C.), University of Minnesota Medical School, Minneapolis, MN.
3. Section of Cardiology, Department of Medicine, University of Illinois at Chicago, IL (A.F.-F.).
4. Division of Cardiology, Department of Medicine, Duke University, Durham, NC (A.F.-F.).
5. Department of Electrical and Computer Engineering, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN (M.A.).
6. Greenberg Cardiology Division, Department of Medicine, Weill Cornell Medical College, New York, NY (J.W.W.).