Abstract
The effects of radiation on the function of two demand-type cardiac pacemakers were investigated. Irradiation was given up to 135 and 100Gy in steps of 1 or 2Gy with 4MV x-rays from a linear accelerator. The effects on sensing (lead) function, electrical circuit and pacing function were observed. Malfunction in lead and battery function occurred after doses of 57 and 70Gy. One pacemaker often showed a pulse width of 0.01msec., indicating a lack of pacing, after a dose of 90Gy. Direct exposure of the pacemaker to radiation was considered to be dangerous.
