[1] Univ Penn, Childrens Hosp Philadelphia, Dept Pediat, Div Cardiol & Clin Futures,Perelman Sch Med, Philadelphia, PA USA
[2] Univ Penn, Leonard Davis Inst Healthcare Econ, Philadelphia, PA USA
[3] Univ Penn, Ctr Cardiovasc Outcomes Quality & Evaluat Res, Perelman Sch Med, Philadelphia, PA USA
[4] Univ Penn, Hosp Univ Penn, Dept Internal Med, Div Cardiol,Perelman Sch Med, Philadelphia, PA USA
[5] Washington Univ, Dept Pediat, Div Cardiol, Sch Med, St Louis, MO USA
[6] St Louis Childrens Hosp, St Louis, MO USA
[7] Univ Penn, Childrens Hosp Philadelphia, Dept Pediat, Div Cardiol & Clin Futures,Perelman Sch Med, 3401 Civ Ctr Blvd, Philadelphia, PA 19104 USA