[1] Mayo Clin, Div Cardiovasc Dis, Dept Internal Med, Rochester, MN 55905 USA
[2] Univ Calif San Diego, Dept Med 0682, San Diego, CA 92103 USA
[3] Univ Naples Federico II, Dept Med, Naples, Italy
[4] Mayo Clin & Mayo Fdn, Dept Internal Med, Div Hypertens, Rochester, MN 55905 USA
[5] Univ Basel Hosp, Div Cardiol, CH-4031 Basel, Switzerland