1. From the Christ Hospital (E.S.C.), Cincinnati, Ohio; Piedmont Hospital (D.D.), Atlanta, Ga; Brigham and Women's Hospital (S.D.S.), Boston, Mass; The St Paul Heart Clinic (A.J.B.), St Paul, Minn; Boston Scientific Corporation (J.P., A.I., C.M.S.), St Paul, Minn; Johns Hopkins Hospital (R.D.B.), Baltimore, Md; Baylor University Medical Center (J.O.F.), Dallas, Tex; Wellmont Holston Valley Medical Center (G.J.), Kingsport, Tenn; and Providence Hospital (C.M.), Southfield, Mich.