Magnetic resonance imaging in patients with cardiac implantable electronic devices: a single-center prospective study

Cardiac implantable electronic devices (CIEDs) have traditionally been a contraindication for magnetic resonance imaging (MRI). Recent studies suggest that MRI can be conducted safely in select patients with pacemakers (PPMs) and implantable cardioverter defibrillators (ICDs). We sought to determine the safety of MRI in patients with CIEDs, using a protocol for patient selection and device programming.

This is a prospective, single-center study. Patients with a PPM or ICD and a clinical indication for MRI were considered. Exclusion criteria included newly implanted devices (<4 weeks), PPMs manufactured before 1996 and ICDs before 2000, epicardial and abandoned leads, and pacemaker-dependent ICD patients. Pacemaker-dependent PPM patients were programmed to asynchronous pacing. Tachycardia detection/therapies were disabled for ICDs. Devices were interrogated pre- and post-scan, and at follow-up 1-6 weeks later. Defibrillation threshold (DFT) was not tested post-scan. Patients were followed to monitor device therapies.

Two hundred twenty-seven patients underwent 293 scans. Devices included 170 (70.6%) PPMs and 71 (29.5%) ICDs. Thirteen (4.4%) scans were aborted mainly due to subjective complaints or artifact on scout cardiac imaging. Post-scan and follow-up interrogation demonstrated no changes in device parameters requiring reprogramming or revision. Over long-term follow-up (median, 354 days [IQR 65-629]), nine ICD patients had appropriate shocks (median, 3 [IQR 1-8]). One had four inappropriate shocks for atrial fibrillation. All tachyarrhythmias meeting criteria for defibrillation were successfully terminated.

MRI can be conducted safely in patients with CIEDs when done in a protocoled manner with appropriate supervision. DFT testing after MRI may not be necessary.