MRI safe for most patients with Pacemakers or Defibrillators

A study by Russo et al published in the NEJM found that MRI scans for patients with older not FDA approved pacemakers and implantable cardioverter-defibrillators (ICD) are safe even if the scan focuses on the chest area.

The researchers performed 1000 MRI in which patients had a pacemaker and in 500 MRI in which patients had an ICD in a 1.5T MRI scanner. No deaths, lead failures, losses of capture, or ventricular arrhythmias occurred during MRI. One ICD generator could not be interrogated after MRI and required immediate replacement; the device had not been appropriately programmed per protocol before the MRI.  Nine of the implants were disrupted but reset themselves to backup mode.  In all but one instance the effect was temporary.

Neither MRI performed on chest or in other parts of the body produced significant complications.   The concerns of potential magnetic field–induced cardiac lead heating, which could result in myocardial thermal injury and/or disrupt pacing properties of the devices were noted in this study.

The authors concluded that in their study, device or lead failure did not occur in any patient who was appropriately screened, and had the device reprogrammed in accordance with the pre-specified protocol.