​In a study involving magnetic resonance imaging (MRI) of patients with implanted pacemakers or implantable cardioverter-defibrillators (ICDs) not approved by the U.S. Food and Drug Administration (FDA) for MRI scanning, no patients who underwent protocol-driven screening and device programming before MRI experienced device or lead failure. According to the study published in the February 23, 2017, issue of the New England Journal of Medicine, implantable cardiac devices that have been designed to reduce MRI risks are FDA labeled as "MRI-conditional" devices. However, at least half of patients with non-MRI-conditional devices have a clinical indication for MRI after the device is implanted. The multicenter study included nonthoracic, 1.5-T MRI scans of adults with non-MRI-conditional devices (1,000 cases in patients with pacemakers and 500 cases in patients with ICDs). No deaths, ventricular arrhythmias, lead failures, or losses of capture occurred during scanning. In one patient, the ICD generator could not be interrogated after MRI, necessitating immediate replacement; however, the device had not been programmed in accordance with protocol before scanning, the authors said. Self-terminating atrial fibrillation or flutter occurred in six cases, and partial electrical reset occurred in six cases. During MRI, four patients reported experiencing discomfort at the generator site; one such patient was removed from the scanner. Changes were observed in a small minority of cases in pacing lead impedance, high-voltage lead impedance, pacing lead threshold, battery voltage, or P-wave or R-wave amplitude over predetermined thresholds. These changes resulted in no clinical adverse events.

HRC Recommends: Patients with implanted cardiac devices may have a clinical indication for MRI scanning. Other imaging modalities might not always adequately meet the patient's clinical need, and removal of implanted generators and leads to facilitate MRI carries risks as well. Risk managers may wish to share information regarding the study with appropriate individuals and departments. However, performing MRI scanning in patients with non-MRI-conditional implantable cardiac devices without comprehensively investigating and evaluating the issue could raise patient safety, liability, and other concerns.