[1] Vanderbilt Univ, Div Cardiol, Med Ctr, Med, Nashville, TN 37232 USA
[2] Univ Naples 2, Cardiol, Naples, Italy
[3] Vanderbilt Univ, Med Ctr, Biostat, Nashville, TN USA
[4] Erasme Univ Hosp, Cardiol, Brussels, Belgium
[5] Vanderbilt Univ, Med Ctr, Div Pulm, Med, Nashville, TN USA