Initial experience with magnetic resonance imaging-safe pacemakers: A review

Due of its superior soft tissue imaging capabilities, magnetic resonance imaging (MRI) has become the imaging modality of choice in many clinical situations, as illustrated by the tremendous growth in the number of MRIs performed over the past 2 decades. In parallel, the number of patients who require pacemakers or implantable cardiac defibrillators is increasing as indications for these devices broaden and the population ages. Taken together, these phenomena present an important clinical issue, as MR scans are generally contraindicated—except in urgent situations—in patients who have implanted cardiovascular devices. Potentially deleterious interactions between the magnetic fields and radio frequency (RF) energy produced by MR equipment and implantable devices have been identified, including inhibition of pacing, asynchronous/high-rate pacing, lead tip heating, and loss of capture. New devices that incorporate technologies to improve MR safety in patients with pacemakers have recently received approval in Europe and are under evaluation in the United States. Initial data from these devices suggest that these devices are safe in the MRI environment

Magnetic resonance imaging in individuals with cardiovascular implantable electronic devices

Magnetic resonance (MR) imaging has unparalleled soft-tissue imaging capabilities. The presence of devices such as pacemakers and implantable cardioverter-defibrillators (ICDs), however, was historically considered a contraindication to MR imaging. We summarize the potential hazards of the device-MR environment interaction, and present updated information regarding in vitro and in vivo experiments suggesting that certain pacemaker and ICD systems may indeed be MR-safe. Recent reports on several hundred patients with implantable pacemakers and ICDs who underwent MR scan safely indicate that, under certain conditions, individuals with these implanted systems may benefit from MR imaging. We believe that, on a case-by-case basis, the diagnostic benefit from MR imaging outweighs the presumed risks for some pacemaker and ICD patients. Thus for some patients, the risks presented by MR imaging under specific, characterized scanning and monitoring conditions may be acceptable given the diagnostic benefit of this powerful imaging modality. This may have major clinical implications on current imaging practice. A strategy for the performance of MR imaging in these individuals is proposed