[1] Royal Prince Alfred Hosp, Dept Cardiol, Camperdown, NSW 2050, Australia
[2] Royal Prince Alfred Hosp, Dept Clin Biochem, Camperdown, NSW 2050, Australia
[3] Univ Sydney, Dept Med, Sydney, NSW 2006, Australia
[4] Turku Univ, Cent Hosp, Dept Clin Physiol, FIN-20520 Turku, Finland