Magnetic Resonance Imaging-Conditional External Cardiac Defibrillator

Magnetic resonance imaging (MRI) is the most rapidly growing imaging modality in clinical medicine, including cardiac disorders.1 One of the limitations of MRI is the need to avoid certain metallic objects in close proximity to the MRI machine, including external cardiac defibrillators. Similarly, patients with implantable devices with ferromagnetic components are contraindicated for MRI because of the risks of heating, dislodgement, and other problems. Included in this contraindicated list are patients with implantable cardiac rhythm devices, although it is estimated that a large number of such patients will be indicated for an MRI.2 This has led to medical device manufacturers modifying the designs of pacemaker systems to make them MRI-conditional. The modifications included using less ferromagnetic material, developing lead wires with reduced radiofrequency heating to prevent thermal damage at the point of contact …