[1] Massachusetts Gen Hosp, Div Cardiol, Boston, MA 02114 USA
[2] Univ Hosp, Dept Cardiol, Maastricht, Netherlands
[3] Christchurch Sch Med & Hlth Sci, Dept Med, Christchurch Cardioendocrine Res Grp, Christchurch, New Zealand
[4] Hosp Santa Creu & Sant Pau, Dept Cardiol, E-08025 Barcelona, Spain
[5] Hosp Santa Creu & Sant Pau, Serv Biochem, E-08025 Barcelona, Spain