Can a patient with a cardiac loop recorder (CLR) have a Magnetic Resonance Imaging (MRI) scan?

MRI in Patients with Cardiac Loop Recorders

Patients with cardiac loop recorders can safely undergo MRI scans at 1.5T with appropriate precautions, though artifacts mimicking arrhythmias are common and should be recognized as such.

Safety Considerations

MRI has traditionally been considered contraindicated in patients with cardiac implantable electronic devices. However, evidence shows that with proper precautions, patients with cardiac loop recorders (CLRs) can safely undergo MRI scanning.

According to the European Society of Cardiology (ESC) guidelines, MRI at 1.5T can be performed with a low risk of complications in patients with conventional cardiac devices when appropriate precautions are taken 1. The guidelines specifically address pacemakers and ICDs, but the principles apply to loop recorders as well.

Safety Evidence for Loop Recorders

Multiple studies have demonstrated the safety of MRI scanning in patients with implantable loop recorders:

• No harm to patients or permanent damage to the devices has been observed 2
• No device movement or heating has been reported during MRI scanning 3
• Device functionality remains unaffected after MRI exposure 2, 3

Important Precautions

When performing MRI on patients with cardiac loop recorders, the following precautions should be taken:

1. Device interrogation before MRI:

   • Clear the device memory before the scan
   • Document baseline device parameters

2. Device interrogation after MRI:

   • Check device parameters immediately after scanning
   • Verify that programmed settings remain unchanged
   • Ensure sensing capabilities are intact

Potential Complications and Limitations

Artifacts

The most significant issue with MRI in patients with loop recorders is the presence of artifacts:

• Both tachy and bradyarrhythmia artifacts are common during MRI scanning 2
• These artifacts can mimic genuine cardiac arrhythmias 3
• Significant hyperintensity artifacts may affect cardiac MRI image quality 4

Clinical Implications

It is crucial to recognize that:

• Artifacts produced during MRI should not be mistakenly attributed to genuine arrhythmias 2
• Any "arrhythmias" detected during the time of MRI scanning should be considered artifacts
• For cardiac MRI specifically, image quality may be compromised due to hyperintensity artifacts 4

Recommendations for Clinical Practice

1. For standard MRI scans (non-cardiac):

   • MRI at 1.5T can be safely performed in patients with cardiac loop recorders
   • Clear the device memory before scanning
   • Perform device interrogation after scanning to verify functionality

2. For cardiac MRI:

   • Be aware that significant artifacts may limit diagnostic value 4
   • Consider alternative imaging modalities if detailed cardiac assessment is needed

3. Documentation:

   • Document the time of MRI scanning in the patient's record
   • Flag any recordings during this period as potential artifacts

Special Considerations

• Newer MR-conditional devices are preferable when available
• When the clinical need for MRI outweighs potential risks, the benefit of obtaining crucial diagnostic information should be prioritized 1
• A consultation with an electrophysiology specialist is warranted before proceeding with MRI 1

In conclusion, while MRI scanning in patients with cardiac loop recorders appears safe for the patient and device, clinicians must be vigilant about artifacts that may mimic arrhythmias and potentially affect image quality, especially for cardiac MRI.