MRI Scans, Pacemakers, and Implantable Cardioverter-Defibrillators: New Safety Evidence

Patients with pacemakers and implantable cardioverter-defibrillators (ICDs) may safely receive magnetic resonance imaging (MRI) testing according to a study from the New England Journal of Medicine. Currently, implanted devices must meet the Food and Drug Administration’s criteria to be considered MRI-conditional. The pacemakers and ICDs that do not meet these requirements are considered legacy devices, and the federal government considers them unsafe for MRI scans. However, the new study proves that, with adherence to protocols, patients with legacy devices can safely receive MRI scans.


The study followed over 1500 patients with implanted devices.


The prospective, nonrandomized study followed 875 patients with pacemakers and 634 with ICDs. All patients had implanted devices that were considered legacy devices —  that is, they did not meet the requirements of the Centers for Medicare & Medicaid Services (CMS). Researchers from the University of Pennsylvania performed MRIs on the patients only when it was deemed clinically necessary.


The scans were done under strict protocols with physicians on hand to monitor patients. Tachyarrhythmia functions were disabled on the machines and pacing modes were appropriately adjusted on the devices.


“We found MRI examinations to be safe in the setting of legacy cardiac pacemakers or ICD systems, when using a safety protocol,” lead study author and University of Pennsylvania professor Saman Nazarian told Cardiovascular Business. “The scans were safely performed even when performing thoracic or cardiac MRI and with patients that were dependent on cardiac pacing for every heartbeat.”


A previous study from MagnaSafe found similar results for non-thoracic scans.


The MagnaSafe Registry is a multi-center study attempting to determine how safe MRIs are for patients with pacemakers and ICDs. They published findings several years ago that upended the traditional view that MRIs were too dangerous for patients with legacy devices. With similar results to Nazarian’s study, MagnaSafe found that there were almost no clinically relevant problems caused by the scan.


This is hugely important because many people with legacy implants are denied MRI scans by Medicare and Medicaid. While doctors may then order computed tomography (CT) scans, MRIs are better at diagnosing certain diseases, particularly in the brain and spinal cord. Nazarian said that if a patient with a legacy device needs an MRI, they should contact a medical center that can safely conduct the scan.


“Many centers across the U.S. are capable of performing safe imaging despite your device,” Nazarian said to Cardiovascular Business. “MRI can be instrumental in providing the right data for appropriate treatment planning in the setting of many neurologic, cardiac and musculoskeletal disorders as well as malignancies.”


The results from the two studies offer compelling evidence that MR technology is safe for those with implanted legacy devices.


According to Robert Russo, a doctor in the MagnaSafe study, more than half of patients with implanted devices will eventually need an MRI. Replacement with an MRI-conditional device is not an option, as the complication risks are too high. Therefore, it’s important to determine the safety of MRI scanning for patients with these legacy devices.


The above studies show how MRIs pose minimal risks while bestowing life-saving advantages for those who need scans. The FDA and CMS have not changed their regulations in light of the findings, but the evidence is mounting that they should consider doing so.




Getting an MRI if you have a pacemaker. Harvard Health Publishing. August 2015;Web. Available from:


Nazarian S et. al. Safety of Magnetic Resonance Imaging in Patients with Cardiac Devices. The New England Journal of Medicine. December 2017;377:2555-2564. doi:10.1056/NEJMoa1604267


Slachta A. MRIs proven safe for patients with with FDA-unapproved implantable devices. Cardiovascular Business. January 2018;Web. Available from: