Cardiac magnetic resonance imaging at 1.5 T in patients with cardiac rhythm devices

Abstract

Recent studies suggest that non-cardiac magnetic resonance imaging (MRI) scanning can be performed safely in selected cardiac rhythm device patients. However, little is known about the safety of performing specific cardiac MRI in this setting. We sought to determine the feasibility of cardiac MRI in patients with pacemakers (PMs) or implantable cardioverter-defibrillators (ICDs). Thirty-eight patients underwent a total of 39 (8 ICDs and 31 PM) cardiac MRI examinations at 1.5 T using usual protocols without specific absorption rate (SAR) restrictions. Nine PM-dependent patients were included. All devices were interrogated before and immediately after MRI. During the scan, pacing mode was programmed to asynchronous for PM-dependent patients whereas ICDs were programmed to a monitor-only mode. All devices were functioning appropriately after cardiac MRI. Comparison of device parameters obtained before and immediately after MRI revealed no significant changes in pacing threshold, lead impedance, battery status, or sensing signal amplitude. Neither clinical events nor patient complaints were reported. Significant imaging artefacts were present on 11 of 39 scans (28.2%). These artefacts were significantly more frequent in ICDs (8 of 8, 100%) vs. PMs (3 of 31, 9.7%) (P < 0.001). Diagnostic questions were answered in 92.3% of the cases, with just three pronounced artefacts preventing an adequate diagnosis in three ICD patients. Our results suggest that cardiac MRI may be performed safely in appropriately selected patients with close monitoring during the scan without limitation of peak SAR level using several precautionary measures. Image artefacts were more frequent in ICD patients.