[1] Univ Cincinnati, Coll Med, Dept Emergency Med, Cincinnati, OH 45267 USA
[2] Univ Alberta, Dept Med, Edmonton, AB, Canada
[3] Duke Clin Res Inst, Durham, NC USA
[4] Henry Ford Hlth Syst, Inst Heart & Vasc, Detroit, MI USA
[5] Univ Massachusetts, Med Ctr, Dept Med, Worcester, MA USA
[6] Cleveland Clin Fdn, Cleveland, OH 44195 USA