[1] Univ Missouri, St Lukes Mid Amer Heart Inst, Kansas City, MO 64111 USA
[2] Boston Univ, Stat Consulting Unit, Boston, MA 02215 USA
[3] Mayo Clin, Rochester, MN USA
[4] Vanderbilt Univ, Med Ctr, Nashville, TN USA
[5] Univ Washington, Med Ctr, Seattle, WA 98195 USA
[6] Beth Israel Deaconess Med Ctr, Boston, MA 02215 USA
[7] Methodist DeBakey Heart Ctr, Houston, TX USA