[1] Northwestern Univ, Dept Med, Div Cardiol, Feinberg Sch Med, Chicago, IL 60611 USA
[2] Univ Pittsburgh, Med Ctr, Dept Internal Med, Pittsburgh, PA 15224 USA
[3] Univ Pittsburgh, Inst Heart & Vasc, Med Ctr, Pittsburgh, PA USA
[4] Univ Pittsburgh, Sch Med, Infect Dis Epidemiol Res Unit, Pittsburgh, PA USA
[5] Univ Pittsburgh, Grad Sch Publ Hlth, Pittsburgh, PA USA
[6] Univ Pittsburgh, Med Ctr, Dept Med, Div Infect Dis, Pittsburgh, PA USA