[1] Rush Univ, Med Ctr, Rush Ctr Congenital & Struct Heart Dis, Chicago, IL 60612 USA
[2] Evelina Childrens Hosp, London, England
[3] Leeds Royal Infirm, Leeds, W Yorkshire, England
[4] John Radcliffe Hosp, Oxford OX3 9DU, England
[5] Bristol Congenital Heart Ctr, Bristol, Avon, England
[6] Our Ladys Hosp Sick Children, Dublin, Ireland