[1] Hosp Univ Penn, Dept Med, Div Cardiol, Philadelphia, PA 19104 USA
[2] Brigham & Womens Hosp, Dept Med, Cardiovasc Div, 75 Francis St, Boston, MA 02115 USA
[3] Northwestern Univ, Dept Med, Feinberg Sch Med, Div Cardiol, Chicago, IL 60611 USA
[4] Univ Minnesota, VA Med Ctr, Minneapolis, MN USA
[5] Univ Montreal, Montreal Heart Inst, Dept Med, Montreal, PQ, Canada
[6] Univ Michigan, Sch Med, Dept Med, Div Cardiol, Ann Arbor, MI 48104 USA
[7] Univ Arizona, Coll Med, Sarver Heart Ctr, Tucson, AZ USA