[1] Cleveland Clin, Dept Emergency Med, Cleveland, OH 44195 USA
[2] Hosp Univ Penn, Dept Emergency Med, Philadelphia, PA 19104 USA
[3] Univ Texas, Sch Med, Div Cardiovasc Med, Houston, TX 77225 USA
[4] Mem Hermann Heart & Vasc Inst, Houston, TX 77225 USA
[5] Stanford Univ, Sch Med, Dept Surg, Div Emergency Med, Stanford, CA 94305 USA