1. From the Cardiology Section, Dartmouth Medical School and Dartmouth-Hitchcock Medical Center, Lebanon, NH (A.V.K., H.S., J.F.R.); Centers for Devices and Radiologic Health, US Food and Drug Administration, Rockville, Md (E.D.H.); Department of Medicine, Brigham and Women’s Hospital, Boston, Mass (R.E.K.); and Cardiovascular Medicine Section, Stanford University, Stanford, Calif (P.F.).