[1] Univ Manitoba, Cardiol Sect, St Boniface Hosp, Winnipeg, MB, Canada
[2] VA North Texas Healthcare Syst, Dept Cardiol, Dallas, TX USA
[3] Univ Texas SW Med Ctr Dallas, Dallas, TX 75390 USA
[4] Columbia Univ, New York, NY USA
[5] Univ Washington, Div Cardiol, Seattle, WA 98195 USA
[6] St Lukes Mid Amer Heart Inst, Kansas City, MO USA
[7] Univ Missouri, Kansas City, MO 64110 USA