Electromagnetic Interference: Sources, Recognition, and Management

Electromagnetic interference (EMI) with implantable devices occurs relatively infrequently. However, it can be responsible for significant clinical and electrocardiographic confusion as well as having the potential to result in significant clinical symptoms. It is often easiest to categorize sources of EMI in terms of the hospital- and nonhospital environments. There are multiple potential sources of EMI within the hospital environment. Being aware of those potential sources and avoiding them, reprogramming devices appropriately and/or reassessing the device post-exposure, should allow the caregiver to avoid most concerns with hospital sources of EMI. EMI is actually less common in the nonhospital environment. However, some industrial sources as well as more commonly used equipment such as welding equipment or electronic article surveillance equipment are capable of causing clinically significant EMI and caregivers and patients should be educated regarding potential sources and how to manage them. The management of specific commonly encountered issues such as electrocautery use and defibrillation are discussed in detail. Also, although MRI has always been considered contraindicated in patients with implantable cardiac devices, MRI conditionally safe pacemakers are now available.