[1] Virginia Commonwealth Univ, Dept Emergency Med & Internal Med, Richmond, VA 23284 USA
[2] Duke Univ Med Ctr, Dept Med & Neurol, Durham, NC USA
[3] Lund Univ, Skane Hosp, Dept Emergency Med, Lund, Sweden
[4] Minneapolis Heart Inst, Minneapolis, MN USA
[5] Columbia Univ, St Lukes Roosevelt Hosp Ctr, Coll Phys & Surg, New York, NY USA