A clinical example of extreme dose exposure for an implanted cardioverter-defibrillator : Beyond the DEGRO guidelines.

Introduction: Considering that the number of malignant diseases in patients over 65 years of age is increasing, it often occurs that patients who carry a cardiac implanted electronic device must undergo radiotherapy. Ionizing radiation can disturb the function of the implantable cardioverter-defibrillator (ICD). As a result of this, an update of the DEGRO/DKG guidelines for radiotherapy of this patient group has been published.

Methods: We report the case of a patient with an ICD and T‑lymphoblastic lymphoma with cardiac involvement, who received i.a. a total body irradiation with 8 Gy followed by a consolidating radiotherapy of the pericardium with 14 Gy as well as additional radiotherapy courses after consecutive recurrences. For the purposes of the treatment, the antitachyarrhythmia (ATA) therapy was deactivated and temporarily replaced through a life vest.

Results: According to the current DEGRO guidelines for irradiation of patients with cardiac implanted electronic devices, a categorization of the patient in the "high-risk" group was made. Furthermore, regular telemetric checks of the ICD device were performed before and after treatment. Despite unavailable declaration of the manufacturer regarding the cumulative tolerable dose and DEGRO recommendation for a cumulative dose <2 Gy, the aftercare was unproblematic and normal values were assessed for all relevant ICD parameters, despite a cumulative dose >10 Gy in the device.

Conclusion: This case shows that if the cardiac implanted electronic devices are not directly irradiated und the energy used is reduced to 6 MV, irradiation-induced damage is less likely and can possibly be prevented.