1. From the Hackensack University Medical Center (T.V.G.), Hackensack, NJ; The Ohio State University Medical Center (E.G.D.), Columbus Ohio; Libin Cardiovascular Institute of Alberta (D.G.W.), Calgary, Alberta, Canada; Massachusetts General Hospital (D.E.S.), Boston, Mass; Lankenau Institute for Medical Research (M.D.E.), Philadelphia, Pa; and Medtronic, Inc (C.H., C.M., D.Q., P.D.Z.), Minneapolis, Minn.