[1] UNIV MARYLAND, SCH MED, DEPT NEUROL, BALTIMORE, MD 21201 USA
[2] UNIV MASSACHUSETTS, SCH MED, DEPT MED, WORCESTER, MA USA
[3] ST LOUIS UNIV, MED CTR, DIV CARDIOL, ST LOUIS, MO 63110 USA
[4] UNIV MINNESOTA, DIV CARDIOL, MINNEAPOLIS, MN USA
[5] ALBERT EINSTEIN COLL MED, DIV CARDIOL, NEW YORK, NY USA
[6] UNIV ALABAMA, MED CTR, DEPT MED, BIRMINGHAM, AL 35294 USA
[7] HARVARD UNIV, SCH MED, DEPT MED, BRIGHAM & WOMENS HOSP, BOSTON, MA USA
[8] HARVARD UNIV, SCH MED, BETH ISRAEL HOSP, BOSTON, MA USA