MRI systems expose patients to very strong magnetic fields that can disrupt electronic pulses generated by a pacemaker. A study performed in 2009 found that the magnetic field can also increase the temperature at the tip of the pacemaker lead within the heart and can cause heart tissue to burn. FDA researchers also found that when the pacemaker is exposed to strong magnetic fields it could drastically alter the pulse and may not stimulate the heart properly. According to the National Council of Aging, a person’s chance of needing an MRI doubles after the age of 65 and 50% to 75% of patients with pacemakers will need an MRI over their lifetime
Magnetic resonance imaging (MRI) is generally contraindicated in patients with pacemakers,and American Heart Association (AHA) guidelines recommend consideration of MRI only in exceptional circumstances,excluding the vast majority of pacemaker patients who might benefit from MRI examination. However, in February 2011, the US Food and Drug Administration (FDA) approved the Revo MRI SureScan Pacing System, the first cardiac pacemaker designed to be used safely during MRI examinations.
For patients without an MRI-safe pacemaker, the electromagnetic fields and radiofrequency (RF) energy generated by MRI may pose risks (eg, interference with pacemaker operation, damage to system components, inappropriate therapy, lead or pacemaker dislodgement, or change in capture threshold). A scientific statement from the AHA on the safety of MRI in patients with cardiovascular devices includes the following limited recommendations on the performance of MRI in patients without an MRI-safe pacemaker or ICD
- Performing the examination at centers with expertise in MRI and electrophysiology
- Having a physician with pacemaker/ICD expertise decide whether it is necessary to reprogram the device before the MRI examination
- Having a person with expertise in MRI physics and safety involved in planning the scan, with consideration for the use of scanning parameters that minimize risk (eg, the lowest RF power levels and the weakest/slowest necessary gradient magnetic fields)
- Testing pacemaker functions before and after the examination
- Observing the patient closely throughout the examination, including monitoring of heart rhythm and vital signs
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