1. From the Department of Surgery, Division of Cardiothoracic Surgery, Carlyle Fraser Heart Center, Emory University School of Medicine, Atlanta, Georgia (J.W.C., M.E.C., J.P.A., C.K.N., B.F.M., R.L.H., S.G., D.J.L.); Department of Integrative Physiology, University of Colorado at Boulder, Boulder, Colorado (A.S., D.R.S.); Johns Hopkins University School of Medicine, Department of Medicine, Division of Cardiology, Baltimore, Maryland (L.A.B.).