Life-threatening pacemaker dysfunction associated with therapeutic radiation: a case report.

Reports about pacemaker (PM) dysfunction during irradiation (IR) are very rare, which is because of the extensive protective mechanisms that exist in these devices against electromagnetic interference (EMI). We report a case in which one of the most clinically relevant type of PM malfunctions, a runaway PM, occurred during radiation in a 76-year-old woman who was treated for inoperable esophageal cancer with a course of photon IR. The estimated IR dose of 0.11 Gy was the lowest in vivo dose ever reported. So a direct radiation effect as cause for this malfunction appears to be improbable. It could be concluded that the PM dysfunction was most likely induced by EMI during radiotherapy. The real reason of the device's software failure remains unclear.