[1] Sunnybrook Res Inst, Sunnybrook Hlth Sci Ctr, Schulich Heart Program, Toronto, ON, Canada
[2] Univ Toronto, Toronto, ON, Canada
[3] McGill Univ, Montreal, PQ, Canada
[4] Keele Univ, Ctr Prognosis Res, Keele Cardiovasc Res Grp, Newcastle, England
[5] Hosp Sick Children, Labatt Family Heart Ctr, Toronto, ON, Canada
[6] Sunnybrook Med Ctr, V106-2075 Bayview Ave, Toronto, ON M4N 3M5, Canada