Cardiovascular Magnetic Resonance in Patients With Magnetic Resonance-Conditional Cardiac Implantable Electronic Devices: What Can We See?

Patients with pacemakers and implantable cardioverter defibrillators (ICDs) have been commonly withheld from magnetic resonance imaging (MRI) procedures because of magnetic resonance (MR) safety concerns. In response to this clinical need, MR-conditional pacemakers and ICDs have been developed to allow these patients access to MRI. The potential interactions between MRI and recently developed MR-conditional implantable electronic devices have been extensively studied and reviewed. These interactions include magnetic force and torque, radio frequency-induced heating, induction of electric currents, and electromagnetic interference. Medical device manufacturers have modified the designs of pacemakers and ICDs by using less ferromagnetic material, developing innovative lead wires to reduce radio frequency heating, and advancing circuitry and shielding to reduce electromagnetic interference. The safety and efficacy of these MR-conditional devices have been the primary end point of the EnRhythm, Advisa, and Evera-MRI trials, among others.