In response to concerns about the risks that individuals with internal defibrillators and pacemakers may face from MRI scans, the findings of a new research suggests that the tests are safe if devices are properly programmed and calibrated.
In a study published last week in the New England Journal of Medicine, researchers with the Scripps Research Institute indicate that there appears to be little or no threat of device or lead failure, even in non-MRI-conditional pacemakers or implantable cardioverter-defibrillators (ICDs), if the devices were properly reprogrammed for MRI scans.
The results come after the FDA issued a warning last month that implanted infusion pumps had been linked to serious injuries and deaths among individuals who underwent MRI scans. In a January 11 safety communication, the agency said it has received reports of medication errors following infusion pump exposure to MRIs, including over-infusion, under-infusion, unintended bolus, pump motors stalling and pump motors not restarting after the MRI exam. The FDA indicates that it is working with manufacturers to update safety labels on infusion pumps to include instructions for safe use in an MR environment.
This latest study found that despite long-standing contraindications for heart implants in nonthoracic MRI scans, there was little threat to properly programmed devices.
Researchers looked at data on about 1,500 patients who underwent MRI scans with either a pacemaker or ICD. The scans were at a field strength of 1.5 tesla and the devices were reprogrammed before scanning and then checked before and after the MRI scan.
The study looked for patient deaths, generator or lead failure, induced arrhythmia and other health problems. In one case, an ICD generator could not be checked, but the device had not been properly reprogrammed. There were six cases of self-terminating atrial fibrillation or flutter, six cases of partial electrical reset, and some changes in battery voltage, pacing threshold and other minor settings in a small number of cases, the researchers report.
There were no deaths, lead failures, loss of capture, or ventricular arrhythmias reported.
“In this study,. device or lead failure did not occur in any patient with a non-MRI-conditional pacemaker or ICD who underwent clinically indicated nonthoracic MRI at 1.5 tesla, was appropriately screened, and ad the device reprogrammed in accordance with the prespecified protocol,” the researchers determined.