1. From the Carolinas Heart Institute, Charlotte, NC (C.A.S., R.M.B., B.H.W.); Washington Hospital Center, Washington, DC (M.B.L., K.M.K., G.S.M., J.J.P.); Beth Israel Deaconess Medical Center, Boston, Mass (D.S.B., K.K.L.H., D.E.C., C.S., R.E.K.); Sequoia Hospital, Redwood City, Calif (T.H.); and Stanford Medical Center, Palo Alto, Calif (P.J.F., P.G.Y.).