Therapeutic irradiation over a permanent cardiac pacemaker.

Therapeutic irradiation of fields containing cardiac pacemakers presents a unique problem to pacemaker physicians and radiation oncologists alike. The present case involved a proposed radiation field containing both subclavian pockets. As an alternative solution, the Cordis model 334A implantable pulse generator was irradiated using a backup temporary pacemaker that was kept outside of any significant radiation exposure. A total of 60 Gy was delivered in 30 fractions, with backup temporary pacing and continuous ECG monitoring used for the first 5 fractions. Frequent re-evaluation of pacing and sensing function revealed no changes as a result of irradiation; following radiotherapy, transtelephonic monitoring showed normal pacemaker function for a 4 month follow-up. This represents a useful alternative, particularly for nonmultiprogrammable pacemakers that are made of more radiation-resistant technology.