[1] UCL, Med Mol Biol Unit, Inst Child Hlth, London WC1N 1EH, England
[2] Univ Michigan, Div Cardiol Veteran Affairs Ann Arbor, Ann Arbor, MI 48109 USA
[3] Wayne State Univ, Sch Med, Div Cardiovasc Dis, Dept Internal Med, Detroit, MI USA
[4] Univ Verona, Div Cardiochirurg, I-37100 Verona, Italy
[5] Univ Westminster, Dept Biomed Sci, London W1W 6UW, England