[1] Univ Michigan, Sch Med, Ann Arbor, MI USA
[2] Childrens Hosp Philadelphia, Philadelphia, PA 19104 USA
[3] Childrens Hosp Wisconsin, Herma Heart Ctr, Milwaukee, WI 53201 USA
[4] Childrens Hosp, Boston, MA 02115 USA
[5] Harvard Univ, Sch Med, Boston, MA USA
[6] NHLBI, NIH, Bethesda, MD 20892 USA
[7] New England Res Inst, Watertown, MA 02172 USA
[8] Med Univ S Carolina, Charleston, SC 29425 USA
[9] Duke Univ, Med Ctr, Durham, NC USA
[10] Hosp Sick Children, Toronto, ON M5G 1X8, Canada
[11] Columbia Univ, Med Ctr, New York, NY USA
[12] Primary Childrens Med Ctr, Salt Lake City, UT 84103 USA
[13] Univ Texas SW Med Ctr Dallas, Dallas, TX 75390 USA