Some cardiovascular implantable devices not designated as safe for MRI scans can actually make it through the scan OK, reports Physicians Briefing.

The study involved 1,246 patients with standard pacemakers or implantable cardioverter-defibrillators (ICDs). They underwent a total of 1,500 MRI scans at 19 centers across the United States. All of the scans were done using the same protocol. Each patient’s device was tested non-invasively before the MRI, then reprogrammed accordingly. If possible, it was set to a no-pacing mode. But if patients had symptoms in that mode, their device was programmed a different way. After the MRI, the device was restored to its original settings, then tested again to make sure it was working properly.

The researchers found that none of the patients had a failure in their device or its wires during the MRI. And none suffered a dangerous heart-rhythm disturbance. Six patients did have atrial fibrillation or atrial flutter but each case was short-lived and stopped on its own. One ICD patient needed to have the device generator immediately replaced after the MRI.