Potential problems with MRI in Pacemaker / ICD (implantable cardioverter-defibrillator) patients

MRI in Pacemaker and ICD patients was generally regarded as contraindicated till recently because of potential interactions between the electromagnetic field and the device. Important aspects to be considered are:

1. Local tissue heating: Device leads (electrodes) pick up energy and transfers it to the cells, causing rise of temperature
2. Arrhythmia induction: Abnormal heart rhythms can originate due to the interference of device function
3. Malfunction of device software and hardware due to interference by the magnetic field
4. Artifacts due to the presence of the device in the image, decreasing the diagnostic accuracy of magnetic resonance imaging (MRI).

The newer MRI conditional devices enable better imaging on following certain preset criteria and precautions. Otherwise MRI is not used in patients with implanted cardiac electronic devices (CIED) like pacemakers and ICDs. MRI is undertaken in such patients only if the estimated benefit far exceeds the potential risks and equivalent information is not obtainable by other imaging modalities like ultrasound or computed tomography (CT).

Read my previous article on MRI conditional pacemakers in BMH Medical Journal: Johnson Francis, MD, DM¹; Kenneth A Ellenbogen, MD.^{2  1}Baby Memorial Hospital, Kozhikode, Kerala, India. PIN: 673004; ²Virginia Commonwealth University School of Medicine, Richmond, VA 23298-0053. Free full text: BMH Med. J. 2014;1(1):9-12.