[1] Stanford Univ, Sch Med, Div Pediat Cardiol, Suite 321,750 Welch Rd, Palo Alto, CA 94304 USA
[2] Cincinnati Childrens Hosp Med Ctr, Heart Ctr, Cincinnati, OH USA
[3] Childrens Mercy Hosp, Div Pediat Cardiol, Kansas City, MO USA
[4] Univ Utah Hlth, Div Pediat Cardiol, Salt Lake City, UT USA
[5] Columbia Univ, Med Ctr, Div Pediat Cardiol, New York, NY USA
[6] Childrens Hosp Philadelphia, Div Pediat Cardiol, Philadelphia, PA USA