title: Clinical safety of the ProMRI pacemaker system in patients subjected to thoracic spine and cardiac 1.5-T magnetic resonance imaging scanning conditions.
abstract: BACKGROUND
  Permanent cardiac pacemakers have historically been considered a contraindication to magnetic resonance imaging (MRI).
  
  
  OBJECTIVE
  The purpose of the ProMRI Phase B Study, a multicenter, prospective, single-arm, nonrandomized study, was to evaluate the clinical safety of the Biotronik ProMRI pacemaker system in patients undergoing thoracic spine and cardiac MRI.
  
  
  METHODS
  The ProMRI Phase B study enrolled 245 patients with stable baseline pacing indices implanted with an Entovis pacemaker (DR-T or SR-T) and Setrox 53-cm and/or 60-cm lead(s). Device interrogation was performed at enrollment, pre- and post-MRI scan, and 1 and 3 months post-MRI. End-points were (1) freedom from MRI- and pacing system-related serious adverse device effects through 1 month post-MRI; (2) freedom from atrial and ventricular MRI-induced pacing threshold increase (>0.5 V); and (3) freedom from P- and R-wave amplitude attenuation (<50%), or P wave <1.5 mV, or R wave <5.0 mV at 1 month post-MRI.
  
  
  RESULTS
  In total, 216 patients completed the MRI and 1-month post-MRI follow-up. One adverse event possibly related to the implanted system and the MRI procedure occurred, resulting in a serious adverse device effect-free rate of 99.6% (220/221; P < .0001. Freedom from atrial and ventricular pacing threshold increase was 100% (194/194, P < .001) and 100% (206/206, P < .001) respectively. Freedom from P- and R-wave amplitude attenuation was 98.2% (167/170, P < .001) and 100% (188/188, P < .001) respectively.
  
  
  CONCLUSIONS
  The results of the ProMRI Phase B study demonstrate the clinical safety and efficacy of the ProMRI pacemaker system in patients subjected to thoracic spine and cardiac MRI conditions.
authors.affiliation: Louisiana Heart Rhythm Specialists and Lafayette General Medical Center, Lafayette, Louisiana. Electronic address: wbailey@heartrhythmmd.com.
authors.forename: William M
authors.initials: WM
authors.lastname: Bailey
authors.affiliation: University of Iowa Hospitals and Clinics, Iowa City, Iowa.
authors.forename: Alexander
authors.initials: A
authors.lastname: Mazur
authors.affiliation: Upstate Cardiology, Greenville, South Carolina.
authors.forename: Craig
authors.initials: C
authors.lastname: McCotter
authors.affiliation: Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Pamela K
authors.initials: PK
authors.lastname: Woodard
authors.affiliation: University of Massachusetts Medical School, Worcester, Massachusetts.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Rosenthal
authors.affiliation: Biotronik Inc, Lake Oswego, Oregon.
authors.forename: Whitney
authors.initials: W
authors.lastname: Johnson
authors.affiliation: Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Theofanie
authors.initials: T
authors.lastname: Mela
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000517:prevention & control*; D002304:Cardiac Pacing, Artificial / Q000379:methods / Q000592:standards; D000075202:Contraindications; D004867:Equipment Design / Q000379:methods; D004868:Equipment Failure / Q000706:statistics & numerical data; D004869:Equipment Safety / Q000379:methods / Q000592:standards; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000009:adverse effects / Q000379:methods / Q000592:standards; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial / Q000592:standards; D011446:Prospective Studies; D013122:Spinal Diseases / Q000175:diagnosis*; D013904:Thoracic Vertebrae / Q000473:pathology*; D016896:Treatment Outcome
keywords: Bradycardia pacing; Clinical trial; ENTOVIS; Magnetic resonance imaging; Pacemaker; ProMRI; Safety