1. From the Departments of Cardiovascular Medicine (E.T.Z., E.M.C., S.G.E., P.J.T., M.K.C.), Thoracic and Cardiovascular Surgery (S.W., E.H.B., E.E.R., N.G.S., A.M.G.), Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH; and ZOLL, Pittsburgh, PA (J.A.G., S.J.S.).