1. From Cardiovascular Engineering Inc (G.F.M.), Waltham, Mass; Brigham and Women’s Hospital (P.R.C., M.A.P.), Boston, Mass; MetroHealth Medical Center (M.E.D.), Cleveland, Ohio; the Centre hospitalier de l’Universite Laval (Y.L.), Ste. Foy, QB; London Health Sciences Centre (J.M.O.A.), London, ON; Toronto Western Hospital (R.I.O.), Toronto, ON; Orange County Research Center (J.N.), Tustin, Calif; and SUNY at Buffalo (J.L.I.), NY.