[1] UT Southwestern Childrens Med Ctr, Dept Pediat, Pediat Cardiol, 1935 Med Dist Dr, Dallas, TX 75235 USA
[2] Childrens Natl Med Ctr, Pediat Cardiol, Washington, DC USA
[3] UT Southwestern Childrens Med Ctr, Dept Pediat, Pediat Cardiac Anaesthesia, Dallas, TX USA
[4] Kings Coll London, Dept Biomed Engn, London, England