title: Impact of magnetic resonance imaging on ventricular tachyarrhythmia sensing: Results of the Evera MRI Study.
abstract: Studies have shown that magnetic resonance imaging (MRI) conditional pacemakers experience no significant effect from MRI on device function, sensing, or pacing. More recently, similar safety outcomes were demonstrated with MRI conditional defibrillators (implantable cardioverter-defibrillator [ICD]), but the impact on ventricular arrhythmias has not been assessed.
  
  
  
  The purpose of this study was to assess the effect of MRI on ICD sensing and treatment of ventricular tachyarrhythmias.
  
  
  
  The Evera MRI Study was a worldwide trial of 156 patients implanted with an ICD designed to be MRI conditional. Device-detected spontaneous and induced ventricular tachycardia/ventricular fibrillation (VT/VF) episodes occurring before and after whole body MRI were evaluated by a blinded episode review committee. Detection delay was computed as the sum of RR intervals of undersensed beats. A ≥5-second delay in detection due to undersensing was prospectively defined as clinically significant.
  
  
  
  Post-MRI, there were 22 polymorphic VT/VF episodes in 21 patients, with 16 of these patients having 17 VT/VF episodes pre-MRI. Therapy was successful for all episodes, with no failures to treat or terminate arrhythmias. The mean detection delay due to undersensing pre- and post-MRI was 0.60 ± 0.59 and 0.33 ± 0.63 seconds, respectively (P = .17). The maximum detection delay was 2.19 seconds pre-MRI and 2.87 seconds post-MRI. Of the 17 pre-MRI episodes, 14 (82%) had some detection delay as compared with 11 of 22 (50%) post-MRI episodes (P = .03); no detection delay was clinically significant.
  
  
  
  Detection and treatment of VT/VF was excellent, with no detection delays or significant impact of MRI observed.
authors.affiliation: Division of Cardiology, Medical University of South Carolina, Charleston, South Carolina. Electronic address: goldmr@musc.edu.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Gold
authors.affiliation: Department of Diagnostic and Interventional Radiology and Nuclear Medicine, German Red Cross Hospital, Neuwied, Germany.
authors.forename: Torsten
authors.initials: T
authors.lastname: Sommer
authors.affiliation: Department of CMR, University Hospital Lausanne, Lausanne, Switzerland.
authors.forename: Juerg
authors.initials: J
authors.lastname: Schwitter
authors.affiliation: Department of Radiology of Neuroradiology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.
authors.forename: Emanuel
authors.initials: E
authors.lastname: Kanal
authors.affiliation: Lancaster Heart and Vascular Institute, Lancaster, Pennsylvania.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Bernabei
authors.affiliation: Department of Cardiology, New York University Langone Medical Center, New York, New York.
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Love
authors.affiliation: Department of Internal Medicine I, Jena University Hospital, Jena, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Surber
authors.affiliation: Mid America Heart Institute, Kansas City, Missouri.
authors.forename: Brian
authors.initials: B
authors.lastname: Ramza
authors.affiliation: Medtronic, plc, Mounds View, Minnesota.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Cerkvenik
authors.affiliation: Heart Center Semmelweis University, Budapest, Hungary.
authors.forename: Béla
authors.initials: B
authors.lastname: Merkely
mesh_terms: D017147:Defibrillators, Implantable; D004562:Electrocardiography; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy
keywords: Implantable cardioverter-defibrillator; Magnetic resonance imaging; Ventricular arrhythmias