[1] Univ Minnesota, Minneapolis, MN USA
[2] Univ Michigan, Ann Arbor, MI 48109 USA
[3] Johns Hopkins Univ Hosp, Baltimore, MD 21287 USA
[4] Columbia Univ, New York, NY USA
[5] Texas Heart Inst, Houston, TX 77025 USA
[6] Massachusetts Gen Hosp, Boston, MA 02114 USA
[7] Thoratec, Pleasanton, CA USA