CyberKnife can cause inappropriate shock

Implantable cardioverter-defibrillators (ICD) have been increasingly used to treat life-threatening ventricular tachyarrhythmias. Although they have life-saving capabilities, they are very sensitive to electromagnetic energy sources. It has been reported that many problems associated with the detection of tachyarrhythmias and termination of the mechanism of the ICDs occur due to electromagnetic interference (EMI). In spite of the fact that EMI has been decreasingly observed with the latest generation ICDs, problems may still occur during radiotherapy. The CyberKnife is the latest stereotactic radio-surgery technology in the field of radiotherapy, and is currently being used for the treatment of malign neoplasm in the body. It is especially preferred for the treatment of advanced stage and metastatic tumors. Five ICD shocks were detected in a patient during a routine follow-up visit. When the patient was evaluated, it was determined that he underwent radiotherapy with CyberKnife technology because of lung metastasis and rectal adenocarcinoma. He received the ICD shocks while he was on radiotherapy. When the stored intracardiac electrograms in the memory of the ICD were investigated, it was established that the shocks were inappropriate shocks due to oversensing because of the exposure to EMI.