Metals of the heart

Can I get my MRI done if I have a pacemaker?

Mr Tan, an 80 year old gentleman had a MRI conditional pacemaker inserted for second degree heart block and now requires a follow-up MRI rectum after rectal surgery a couple of months ago. His son, a lawyer, asks our MR radiographer if his father is able to proceed with the MRI examination given this situation.

MRI is safe for most people with pacemakers and defibrillators

MRI has long been considered dangerous for people who have electronic heart devices like pacemakers and defibrillators implanted in their bodies. However, in a few studies published in 2017, it was concluded that it is safe for patients with electronic heart devices to undergo an MRI.

Previously, most devices were not FDA-approved for MRI. They were thought to be risky because it was feared that the high-strength magnetic field used for scanning could disrupt the device’s circuits and result in a heart rhythm disturbance. Yet when the researchers reviewed about 200 MRI studies involving 180 patients with non-FDA approved devices, they did not find a problem with how they functioned.

In the last 10 years, the FDA has approved newer electronic heart devices that are designed to be relatively safe for MRI; these are labeled “MRI conditional.” Most heart devices that are implanted these days are “MRI conditional”. “MRI conditional” is used to describe an item that has been shown to pose no known hazards in a specified MR environment with specified conditions of use.

Standard procedure before and after your MRI

You will need to see your cardiologist for review of your heart condition, pacemaker history and system. Thereafter, the vendor of your heart device (example Medtronic, Boston Scientific or St Jude Medical) will program and restore the original program settings before and after your scan respectively.

During your MRI

You will be on continuous ECG and vital signs monitoring during your scan, with our radiologist on standby. Our MR radiographer will keep checking to see if you are alright throughout the entire scan, using the microphone. In cases like this, our MR radiographer will ensure the appropriate MR parameters conforming to device safety instructions are adhered to and limit the time you spend in the MRI scanner, without compromise of image quality.

Mr Tan’s MRI was uneventful. He had his pacemaker settings restored and the device interrogated by the vendor after the scan.

Extract from the patient’s cardiologist correspondence letter with our radiologist:
“He had a dual chamber cardiac pacemaker implanted on 13 January 2020 for second degree AV block with symptomatic bradycardia. He has syncopal episodes then. He was started on Coralan 2.5 mg TDS.

He was seen at my clinic and had MRI mode activated for his pacemaker with mode switched to DOO at 70 bpm. Post MRI, the MRI mode was switched off and pacemaker was checked. Pacemaker status: Battery: 3.15 (10.7 years); RA: 1.1 mV / 339 ohms/ 0.75V@0.4 ms; RV; 3.9 mV/ 513ohms/0.75V@0.4ms.”

References:
Mason S et al. Real world MRI experience with nonconditional and conditional cardiac rhythm devices after MagnaSafe. J Cardiovasc Electrophysiol. 2017 Dec;28(12):1468-1474.

Muthalay RG et al. MRI in Patients with Cardiac Implantable Electronic Devices. Radiology. 2018 Nov;289(2):281-292.

Maass AH, Hemels MEW and Allaart CP. Magnetic resonance imaging in patients with cardiac implantable electronic devices. Neth Heart J. 2018 Dec; 26(12): 584–590.

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