Introduction Although most pacemakers and defibrillators currently implanted are MRI-conditional, many still have legacy non-MRI conditional devices. Even following box-change to an MRI-conditional generator, these systems remain classed non-MRI conditional due to the leads, resulting in problems for patients accessing MRI. We therefore compared the effect of 1.5 T MRI on non-MRI conditional and MRI-conditional leads.
Methods Patients undergoing MRI for clinical indications in two centres over 2.5 years were included. Patients were scanned at 1.5 T according to institutional protocols, with devices interrogated pre- and post-scan, and complications recorded. Analysis of changes to lead parameters peri-scan were stratified by MRI-conditionality and presented as mean (95% confidence interval).
Results 201 MRI examinations (64% cardiac) were performed with no clinical complications in 185 patients (75 with defibrillators, 60 pacemaker-dependent). Of 442 leads scanned, 152 (34%) were non-conditional. Overall following MRI, although atrial lead amplitude reduced by 0.17 (0.05, 0.35) mV (p=0.008) with small statistically significant changes to lead impedance, pacing thresholds were unchanged. There were no significant differences in changes peri-scan between MRI-conditional and non-MRI conditional leads, including defibrillator leads (p=NS for all parameters). Parameter changes exceeding pre-specified cut-offs occurred in 25% of MRI-conditional and 21% non-MRI conditional leads. There was no influence of generator or lead age, or thoracic imaging on lead parameter changes.
Discussion This study suggests the risk of scanning non-MRI conditional leads is no greater than with MRI-conditional leads. Larger studies are warranted to assess whether patients with MRI-conditional generators but non-MRI conditional leads should be re-stratified as ‘MRI-conditional’.
Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.