Pacemaker failure resulting from radiation damage.

The authors present a case of radiation-induced pacemaker failure. After 2,000 rad (20 Gy) of photon irradiation for metastatic bronchogenic carcinoma, the pulse generator circuitry failed, producing a "runaway" rhythm. This suggests that present pacemaker circuitry may be more susceptible to irradiation than previously believed, and that even modest radiation doses can induce life-threatening arrhythmias.