Immediate and 12 months follow up of function and lead integrity after cranial MRI in 356 patients with conventional cardiac pacemakers

Background: conventional cardiac pacemakers are still often regarded as a contraindication to magnetic resonance imaging (mri). we conducted this study to support the hypothesis that it is safe to scan patients with cardiac pacemakers in a 1.5 tesla mri,if close supervision and monitoring as well as adequate pre- and postscan programming is provided. methods. we followed up 356 patients (age 61.3 ± 9.1 yrs.,229 men) with single (n = 132) or dual chamber (n = 224) cardiac pacemakers and urgent indication for a cranial mri for 12 months. the scans were performed at 1.5t. during the scan patients were monitored with a 3-lead ecg and pulse oximetry. prior to the scan pacemakers were programmed according to our own protocol. results: all 356 scans were completed without complications. no arrhythmias were induced,programmed parameters remained unchanged. no pacemaker dysfunction was identified. follow-up examinations were performed immediately,2 weeks,2,6,and 12 months after the scan. there was no significant change of pacing capture threshold (ventricular 0.9 ± 0.4 v@0.4 ms,atrial 0.9 ± 0.3 v@0.4 ms) immediately (ventricular 1.0 ± 0.3 v@0.4 ms,atrial 0.9 ± 0.4 v@0.4 ms) or at 12 months follow-up examinations (ventricular 0.9 ± 0.2 v@0.4 ms,atrial 0.9 ± 0.3 v@0.4 ms). there was no significant change in sensing threshold (8.0 ± 4.0 mv vs. 8.1 ± 4.2 mv ventricular lead,2.0 ± 0.9 mv vs. 2.1 ± 1.0 mv atrial lead) or lead impedance (ventricular 584 ± 179 ω vs. 578 ± 188 ω,atrial 534 ± 176 ω vs. 532 ± 169 ω) after 12 months. conclusions: this supports the evidence that patients with conventional pacemakers can safely undergo cranial mri in a 1.5t system with suitable preparation,supervision and precautions. long term follow-up did not reveal significant changes in pacing capture nor sensing threshold. © 2014muehling et al.; licensee biomed central ltd.