In this article, we demonstrated that certain older cardiac pacemakers are more susceptible to “power-on reset” (PoR) when exposed to magnetic resonance
“Power-on resets” in cardiac implantable electronic devices during magnetic resonance imaging
Introduction
Magnetic resonance imaging (MRI) is the imaging modality of choice for many disorders of the brain, spine, and musculoskeletal system. With an aging population and increased use of cardiac implantable electronic devices (CIEDs), it is increasingly likely that patients with CIEDs will need an MRI during their life span.1 MRI in patients with CIEDs, however, is “discouraged” or “should not be performed.”2 It should only be considered in situations when there is a clear clinical indication and the benefits outweigh the risks.3
In the past few years, several studies have demonstrated the safety of MRI in select patients with non–MRI-conditional CIEDs under close clinical supervision.4, 5, 6, 7, 8 Patients who are pacemaker dependent have been excluded from many protocols, partly because of the potential for power-on reset (PoR). A PoR may cause the CIED to revert to its factory default settings. Instead of programmed asynchronous pacing used during MRI in a pacemaker-dependent patient, the device may be reset to an inhibited mode. Electromagnetic interference (EMI) during MRI could cause inappropriate inhibition of pacing, resulting in asystole.9, 10, 11 Because MRI may at times be required in pacemaker-dependent patients, a better understanding of the risk factors for PoR is needed. Accordingly, our aim was to review our experience performing MRI in patients with CIEDs to determine the incidence of and risk factors for PoR.
Section snippets
Methods
A prospective study was performed at Mayo Clinic, Rochester, MN, between January 2008 and May 2013 in patients with non–MRI-conditional CIEDs undergoing clinically indicated MRI with the approval of the institutional review board. In consultation with the referring physician, the radiologist decided whether alternative imaging modalities could provide similar information at less risk to the patient. If it was determined that MRI was the preferred imaging modality, the referring clinician
Results
MRI scans (N = 279) were performed in 219 patients with CIEDs. Twenty-three scans in 21 patients were excluded because patients had MRI-conditional devices. This yielded 256 MRI scans performed in 198 patients. The median age was 66 years (IQR 55–77 years), and 59.4% of patients were men (Table 1). Overall, devices were implanted a median of 30.2 months (IQR 12.8–53.6 months) before MRI. A majority of CIEDs (54.3%) were manufactured by Medtronic (Minneapolis, MN), with Boston Scientific
Discussion
PoR is a safety feature meant to ensure minimal pacemaker functionality in situations in which the generator may not function properly. The typical factory default mode is VVI (inhibited pacing mode) in pacemakers and activated tachyarrhythmia therapies in ICDs.9, 10 PoR can occur when a CIED is exposed to strong electromagnetic fields during MRI. Patients who are pacemaker dependent or who have a slow intrinsic rate are at particular danger of complications from PoR, which could result in
Conclusion
PoR occurs infrequently but can cause deleterious changes in CIED function. MRI should not be performed in pacemaker-dependent patients with older at-risk generators (market release 2002 or before). Continuous monitoring during MRI is essential, as unrecognized PoR may inhibit pacing or accelerate battery depletion due to high pacing output.
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2020, Magnetic Resonance Imaging Clinics of North AmericaCitation Excerpt :The CIED is programmed to asynchronous mode with deactivation of advanced features. Particularly in older CIEDs, power on resets can be encountered rarely in MR imaging22 and this can be particularly concerning when scanning pacemaker-dependent patients. With the adoption of this approach, in the United States, the Centers for Medicare and Medicaid Services permits reimbursement for MR examinations performed in patients with nonconditional CIED systems.
Joint Position Paper of the Working Group of Pacing and Electrophysiology of the French Society of Cardiology (SFC) and the Société française d'imagerie cardiaque et vasculaire diagnostique et interventionnelle (SFICV) on magnetic resonance imaging in patients with cardiac electronic implantable devices: MRI in patients with cardiac electronic implantable devices: Joint Position Paper of the SFC and SFICV
2020, Diagnostic and Interventional ImagingCitation Excerpt :The mechanical switch of MR-nonconditional generators can be activated by MR, thereby resulting in asynchronous pacing in pacemakers or deactivation of tachycardia detection in ICDs [10]. All magnetic fields can cause electrical reset of MR-nonconditional generators leading to back-up in emergency mode with VVI pacing and reactivation of therapies that could cause pacing inhibition or inappropriate shocks [11–13]. Rapid depletion of the battery can also occur [14].
Pacemaker and Implantable Cardioverter-Defibrillator Safety and Safe Scanning
2018, Cardiovascular Magnetic Resonance: A Companion to Braunwald’s Heart DiseaseSCMR expert consensus statement for cardiovascular magnetic resonance of patients with a cardiac implantable electronic device
2024, Journal of Cardiovascular Magnetic ResonanceJoint Position Paper of the Working Group of Pacing and Electrophysiology of the French Society of Cardiology and the French Society of Diagnostic and Interventional Cardiac and Vascular Imaging on magnetic resonance imaging in patients with cardiac electronic implantable devices
2020, Archives of Cardiovascular DiseasesCitation Excerpt :The mechanical switch of MR-non-conditional generators can be activated by MRI, thereby resulting in asynchronous pacing in pacemakers or deactivation of tachycardia detection in ICDs [10]. All magnetic fields can cause electrical reset of MR-non-conditional generators, leading to backup in emergency mode with VVI pacing and reactivation of therapies that could cause pacing inhibition or inappropriate shocks [11–13]. Rapid depletion of the battery can also occur [14].
This work was funded entirely by Mayo Clinic.