[1] St Thomas Hosp, Rayne Inst, Div Cardiovasc, Kings Coll London,BHF Ctr,Rayne Inst, London SE1 7EH, England
[2] Univ Calif Los Angeles, Dept Anesthesiol, Los Angeles, CA 90095 USA
[3] Univ Calif Los Angeles, Dept Physiol, Los Angeles, CA 90095 USA
[4] Univ Calif Los Angeles, Dept Med, Los Angeles, CA 90095 USA