Key result
MRI at 1.5-T causes zero adverse events in pacemaker patients, with ~9% lead threshold changes.
Why the study?
MRI is considered an absolute contraindication for patients with pacemakers due to theoretical risks, yet there are clinical situations when an MRI at 1.5-Tesla is needed.
Can patients with cardiac pacemakers safely undergo magnetic resonance imaging at 1.5-Tesla?
Observational (n=54)
Can patients with cardiac pacemakers safely undergo magnetic resonance imaging at 1.5-Tesla?
Patients with unrestricted cardiac pacemakers were able to undergo 1.5-Tesla MRI examinations with continuous monitoring and pre/post interrogation without adverse events, challenging its status as an absolute contraindication.
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“We stand by our original conclusions. Performance of MRI in appropriately selected, nonpacemaker-dependent patients can be accomplished with an acceptable safety profile. Precautions must include continuous monitoring of the patient with ECG and intermittent voice contact, resuscitation equipment on standby, adequate personnel to move and resuscitate the patient should the need arise, and the presence of a person facile in pacemaker interrogation and programming.”
Supports MRI consideration in pacemaker patients; challenges absolute contraindication yet leaves open need for randomized trials.
Objectives The study was done to determine whether patients with pacemakers could safely undergo magnetic resonance imaging (MRI) at 1.5-Tesla (T). Background Because of theoretical risks, it is an absolute contraindication for a patient with a pacemaker to undergo MRI. However, there are times when an MRI is needed to provide valuable clinical information. Methods Fifty-four patients underwent a total of 62 MRI examinations at 1.5-T. The type of MRI examination was not limited and included cardiac, vascular, and general MRI studies using various whole-body averaged specific absorption rate (SAR) of radiofrequency power. Restrictions were not placed on the type of pacemaker present in the patient. All pacemakers were interrogated immediately before and after MRI scanning, and patients were continuously monitored. Before and after MRI, interrogation was done, and pacing and sensing thresholds, as well as lead impedances, were all measured. Results A total of 107 leads and 61 pulse generators were evaluated. No adverse events occurred. Forty (37%) of the leads underwent changes, whereas 10 (9.4%) leads underwent a significant change. Only 2 of the 107 (1.9%) leads required a change in programmed output. Threshold changes were unrelated to cardiac chamber, anatomical location, peak SAR, and time from lead implant to the MRI examination. Electrocardiographic changes and patient symptoms were minor and did not require cessation of MRI. Conclusions Safety was demonstrated in this series of patients with pacemakers at 1.5-T.
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Martin et al. (2004) conducted an observational in Patients with cardiac pacemakers undergoing magnetic resonance imaging (n=54). 1.5-Tesla Magnetic Resonance Imaging (MRI) vs. Pre-MRI baseline pacemaker interrogation was evaluated on Adverse events and significant pacemaker lead threshold changes. MRI at 1.5-Tesla in patients with pacemakers resulted in 0 adverse events, with 9.4% of leads showing significant threshold changes and 1.9% requiring output reprogramming.
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