title: Immediate and 12 months follow up of function and lead integrity after cranial MRI in 356 patients with conventional cardiac pacemakers.
abstract: 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.
authors.affiliation: Cardiology Clinic Harlaching, University of Munich, Munich, Germany. DrMuehling@aol.com.
authors.forename: Olaf M
authors.initials: OM
authors.lastname: Muehling
authors.forename: Reza
authors.initials: R
authors.lastname: Wakili
authors.forename: Martin
authors.initials: M
authors.lastname: Greif
authors.forename: Franz
authors.initials: F
authors.lastname: von Ziegler
authors.forename: Dominik
authors.initials: D
authors.lastname: Morhard
authors.forename: Hartmut
authors.initials: H
authors.lastname: Brueckmann
authors.forename: Alexander
authors.initials: A
authors.lastname: Becker
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D001927:Brain Diseases / Q000175:diagnosis* / Q000473:pathology; D002304:Cardiac Pacing, Artificial; D000075202:Contraindications; D004562:Electrocardiography; D004867:Equipment Design; D004868:Equipment Failure; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D010138:Pacemaker, Artificial; D061214:Patient Safety; D011237:Predictive Value of Tests; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors