1. Brigham and Women’s Hospital Heart & Vascular Center and Harvard Medical School, Boston, MA (M.V., A.Q., D.L.B.).
2. Department of Medicine, Massachusetts General Hospital, Boston (A.N.).
3. Division of Cardiology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL (R.B.P., C.W.Y.).
4. Duke Clinical Research Institute and Division of Cardiology, Duke University Medical Center, Durham, NC (A.M.N., E.D.P.).
5. Ahmanson–UCLA Cardiomyopathy Center, University of California Los Angeles (G.C.F.).
6. Division of Cardiology, Stony Brook University, NY (J.B.).