title: Safety of magnetic resonance imaging in patients with permanent pacemakers: a collaborative clinical approach.
abstract: OBJECTIVE
  This study aimed to characterize the interactions of pacemakers with magnetic resonance imaging (MRI) and to identify device characteristics that could predict adverse interactions.
  
  
  BACKGROUND
  The safety of MRI in patients with indwelling pacemaker systems remains uncertain. Previous studies demonstrated safety in most patients, but unpredictable, potentially concerning changes in pacemaker behavior have occurred.
  
  
  METHODS
  We prospectively studied patients with pacemaker devices in situ who were not pacemaker dependent and in whom MRI was essential for adequate diagnosis and treatment. All patients were monitored by electrocardiography and pulse oximetry during scanning; devices were interrogated and cardiac enzymes were measured before and after scanning.
  
  
  RESULTS
  Of 32 patients studied (46 MRI examinations), 28 patients had a dual-chamber system and one had a biventricular device. Regions scanned were the head and spine. Devices were reprogrammed to asynchronous pacing or sense-only mode in all except six patients before MRI. During six scanning episodes (five patients), "power-on" resetting of the device was noted. Magnet-mode pacing was noted during four episodes (three patients). Occasional premature ventricular contractions were noted in one patient. No significant changes in battery voltage, sensed P wave and R wave, pacing thresholds, lead impedance, or cardiac enzymes were noted immediately after MRI or at 1-month follow-up.
  
  
  CONCLUSIONS
  Overall, no significant changes were seen in pacemaker device function, and no adverse clinical events were observed. A minority of patients with older devices had unpredictable changes in device behavior, which stresses the need for close monitoring during and careful device interrogation after scanning.
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN 55905, USA. boilson.barry@mayo.edu
authors.forename: Barry Anthony
authors.initials: BA
authors.lastname: Boilson
authors.forename: Anita
authors.initials: A
authors.lastname: Wokhlu
authors.forename: Nancy G
authors.initials: NG
authors.lastname: Acker
authors.forename: Joel P
authors.initials: JP
authors.lastname: Felmlee
authors.forename: Robert E
authors.initials: RE
authors.lastname: Watson
authors.forename: Paul R
authors.initials: PR
authors.lastname: Julsrud
authors.forename: Paul A
authors.initials: PA
authors.lastname: Friedman
authors.forename: Yong-Mei
authors.initials: YM
authors.lastname: Cha
authors.forename: Robert F
authors.initials: RF
authors.lastname: Rea
authors.forename: David L
authors.initials: DL
authors.lastname: Hayes
authors.forename: Win-Kuang
authors.initials: WK
authors.lastname: Shen
mesh_terms: D000368:Aged; D000075202:Contraindications; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000009:adverse effects; D008297:Male; D008991:Monitoring, Physiologic; D010138:Pacemaker, Artificial; D061214:Patient Safety; D012984:Software