Children's & Women's Health Centre of British Columbia (Claydon, Popescu, Christopherson, Human, Solimano, Lavoie); Divisions of Neonatology (Popescu, Shaiba, Solimano, Lavoie) and Cardiology (Human), Department of Pediatrics, University of British Columbia; British Columbia Children's Hospital Research Institute (Popescu, Human, Lavoie), Vancouver, BC; Victoria General Hospital (Taylor), Victoria, BC; University of Toronto (Shaiba), Toronto, Ont.