[1] Queens Univ, Kingston, ON, Canada
[2] Childrens Hosp Eastern Ontario, Ottawa, ON, Canada
[3] Stanford Univ, Stanford, CA 94305 USA
[4] Hosp Sick Children, Toronto, ON, Canada
[5] Fdn Cardiofantil, Inst Cardiol, Bogota, Colombia
[6] Texas Childrens Hosp, Houston, TX 77030 USA
[7] Childrens Mercy Kansas City, Kansas City, MO USA
[8] Childrens Hosp Montefiore, New York, NY USA
[9] Childrens Hosp Philadelphia, Philadelphia, PA 19104 USA
[10] Mt Sinai Hosp, New York, NY 10029 USA
[11] Univ Miami, Miami, FL USA
[12] Emory Univ, Sch Med, Atlanta, GA USA
[13] Ann & Robert H Lurie Childrens Hosp, Chicago, IL USA
[14] UPMC Childrens Hosp Pittsburgh, Pittsburgh, PA USA
[15] Hosp Italiano Buenos Aires, Buenos Aires, DF, Argentina
[16] Rocky Mt Hosp Children, Denver, CO USA
[17] Primary Childrens Med Ctr, Salt Lake City, UT USA
[18] Childrens Hosp Los Angeles, Los Angeles, CA 90027 USA
[19] Univ Chicago, Chicago, IL 60637 USA
[20] Boston Childrens Hosp, Boston, MA USA
[21] Univ Calif San Francisco, San Francisco, CA 94143 USA
[22] Univ Maryland, Sch Med, Baltimore, MD 21201 USA
[23] Johns Hopkins Univ Hosp, Baltimore, MD 21287 USA
[24] Univ Manitoba, Winnipeg, MB, Canada
[25] Yale Univ, Sch Med, New Haven, CT USA
[26] Med Coll Wisconsin, Milwaukee, WI 53226 USA
[27] Childrens Hosp & Inst Child Hlth, Lahore, Pakistan
[28] Wenzhou Med Univ, Affiliated Hosp 1, Wenzhou, Peoples R China
[29] Columbia Columbia Univ, New York, NY USA