[1] Mayo Clin & Mayo Fdn, Dept Internal Med, Div Hypertens, Rochester, MN 55905 USA
[2] Mayo Clin & Mayo Fdn, Dept Internal Med, Div Cardiovasc, Rochester, MN 55905 USA
[3] Natl Cardiovasc Ctr, Res Inst, Suita, Osaka 565, Japan
[4] Univ Naples Federico II, Dept Med, Naples, Italy
[5] Univ Calif San Diego, Dept Med 0682, San Diego, CA 92103 USA