Magnetic resonance imaging (MRI) may be safely performed on patients with specially designed implantable cardioverter-defibrillators (ICD), according to a new study published May 14 in the Journal of the American College of Cardiology and presented at Heart Rhythm 2015 in Boston. The study is the first human study of an MRI safe ICD designed for full body imaging.

Since the approval of the ICD 30 years ago, many advances have been made to improve the device. MRIs, however, have been off limits for patients with ICDs due to presumed risks of the scans for this group. In the study, 263 patients were implanted with the Evera MRI^TM ICD (MR-ICD), and randomly assigned to an MRI with a 1.5 Telsa system or to undergo a waiting period without an MRI.

Overall results found the MR-ICD to be “safe with MRI examinations, showing no evidence of causing any adverse effect on the electrical performance or the ability to treat ventricular arrhythmias.” Of the 156 patients who underwent an MRI, 147 were followed for at least one month. None of the patients experienced an MRI-related complication. Pacing and sensing of the ICDs were not significantly impacted by the MRI.

In an accompanying editorial comment, Arthur J. Moss, MD, FACC, et al. note that the “trial has significantly advanced safe MRI studies using 1.5 Tesla output in patients with the new, conditional ICD.” “It is clear that new upgrades of the ICD are becoming safer in patients undergoing MRI studies,” they write. “It is only a matter of time before all cardiac electronic device manufacturers will have MRI-compatible pacemakers, ICDs and CRTs available.”

Keywords: Arrhythmias, Cardiac, Defibrillators, Implantable, Heart Conduction System, Magnetic Resonance Imaging

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