MRI scanning in patients with new and existing CapSureFix Novus 5076 pacemaker leads: randomized trial results

Background: Magnetic resonance imaging (MRI) can be safely performed in patients with magnetic resonance (MR)-conditional pacemaker systems but remains relatively contraindicated with non-MR-conditional pacemaker systems.

Objective: The purpose of this study was to evaluate the safety of MRI without positioning restrictions in patients with an MR-conditional pacemaker and currently a non-MR-conditional Medtronic CapSureFix Novus 5076 lead(s).

Methods: The study randomized 266 patients in a 2:1 ratio to the MRI group (177 patients) or to the control group (89 patients). At 9-12 weeks postimplant, the MRI group underwent MRI at 1.5 T. Primary end points were MRI-related complication-free rate and noninferiority of the MRI group compared to the control group with regard to the proportion of patients with an increase of ≤0.5 V in right atrial (RA) and right ventricular (RV) pacing capture thresholds from immediately before MRI to 1-month after MRI.

Results: No MRI-related complications occurred in 156 MRI-scanned patients who were followed through 1-month post-MRI. Differences in the proportion of patients with ≤0.5 V pacing capture threshold changes from pre-MRI to 1-month post-MRI were minimal between the groups for RA (proportions of 100% in both groups; a P value cannot be calculated) and RV leads (proportions of 99.3% in the MRI group and 100% in the control group; noninferiority test, P < .0001). Proportions of patients with acceptable sensing amplitude changes from pre-MRI to 1-month post-MRI were also similar between the 2 groups for RA and RV leads (noninferiority test, P < .0001 and P = .0004, respectively). No arrhythmias occurred during MRI.

Conclusion: MRI scans can be performed safely without positioning restrictions in patients with Medtronic CapSureFix Novus 5076 leads connected to an MR-conditional pacemaker.