RT Journal Article SR Electronic T1 The pacemaker challenge JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP 28 OP 31 VO 110 IS 1 A1 Goldman, B. S. A1 Noble, E. J. A1 Heller, J. G. A1 Covvey, D. YR 1974 UL http://www.cmaj.ca/content/110/1/28.abstract