[1] Univ Groningen, Univ Med Ctr Groningen, Dept Cardiol, NL-9700 RB Groningen, Netherlands
[2] Duke Univ, Med Ctr, Duke Clin Res Inst, Durham, NC USA
[3] Mazankowski Alberta Heart Inst, Edmonton, AB, Canada
[4] Duke Translat Med Inst, Durham, NC USA
[5] Univ Maryland Hosp, Div Cardiol, Baltimore, MD 21201 USA
[6] Cleveland Clin Fdn, Cleveland, OH 44195 USA
[7] British Heart Fdn, Cardiovasc Res Ctr, Glasgow, Lanark, Scotland
[8] Cent Hosp Stavanger, Div Cardiol, Stavanger, Norway