[1] Washington Univ, St Louis Childrens Hosp, Div Cardiol, St Louis, MO 63110 USA
[2] Cleveland Clin Fdn, Dept Pediat Cardiol, Cleveland, OH 44195 USA
[3] Columbia Univ, New York Presbyterian Hosp, Div Pediat Cardiol, New York, NY USA
[4] Univ Utah, Primary Childrens Med Ctr, Div Pediat Cardiol, Salt Lake City, UT USA
[5] Northwestern Univ, Childrens Mem Hosp, Div Cardiol, Chicago, IL 60614 USA
[6] Harvard Univ, Sch Med, Childrens Hosp, Dept Cardiol, Boston, MA USA