title: Full-Body MRI in Patients With an Implantable Cardioverter-Defibrillator: Primary Results of a Randomized Study.
abstract: BACKGROUND
  Magnetic resonance imaging (MRI) of patients with conventional implantable cardioverter-defibrillators (ICD) is contraindicated.
  
  
  OBJECTIVE
  This multicenter, randomized trial evaluated safety and efficacy of a novel ICD system specially designed for full-body MRI without restrictions on heart rate or pacing dependency. The primary safety objective was >90% freedom from MRI-related events composite endpoint within 30 days post-MRI. The primary efficacy endpoints were ventricular pacing capture threshold and ventricular sensing amplitude.
  
  
  METHODS
  Subjects received either a single- or dual-chamber ICD. In a 2:1 randomization, subjects either underwent MRI at 1.5-T of the chest, cervical, and head regions to maximize radiofrequency exposure up to 2 W/kg specific absorption rate and gradient field exposure to 200 T/m/s per axis (MRI group, n = 175), or they underwent a 1-h waiting period without MRI (control group, n = 88). A subset of MRI patients underwent ventricular fibrillation induction testing post-MRI to characterize defibrillation function.
  
  
  RESULTS
  In 42 centers, 275 patients were enrolled (76% male, age 60.4 ± 13.8 years). The safety endpoint was met with 100% freedom from the composite endpoint (p < 0.0001). Both efficacy endpoints were met with minimal differences in the proportion of MRI and control patients who demonstrated a ≤0.5 V increase in ventricular pacing capture threshold (100% MRI vs. 98.8% control, noninferiority p < 0.0001) or a ≤50% decrease in R-wave amplitude (99.3% MRI vs. 98.8% control, noninferiority p = 0.0001). A total of 34 ventricular tachyarrhythmia/ventricular fibrillation episodes (20 induced; 14 spontaneous) occurred in 24 subjects post-MRI, with no observed effect on sensing, detection, or treatment.
  
  
  CONCLUSIONS
  This is the first randomized clinical study of an ICD system designed for full-body MRI at 1.5-T. These data support that the system is safe and the MRI scan does not adversely affect electrical performance or efficacy. (Confirmatory Clinical Trial of the Evera MRI System for Conditionally-Safe MRI Access; NCT02117414).
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: Prince Sultan Cardiac Center, Riyadh, Saudi Arabia.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Al Fagih
authors.affiliation: Central Coast Cardiology, Salinas, California.
authors.forename: Timothy
authors.initials: T
authors.lastname: Albert
authors.affiliation: Heart Center Semmelweis University, Budapest, Hungary.
authors.forename: Béla
authors.initials: B
authors.lastname: Merkely
authors.affiliation: United Heart and Vascular Clinic, Minneapolis, Minnesota.
authors.forename: Michael
authors.initials: M
authors.lastname: Peterson
authors.affiliation: Sentara Norfolk General Hospital, Norfolk, Virginia.
authors.forename: Allen
authors.initials: A
authors.lastname: Ciuffo
authors.affiliation: Washington Hospital Center, Washington, DC.
authors.forename: Sung
authors.initials: S
authors.lastname: Lee
authors.affiliation: Medtronic, Minneapolis, Minnesota.
authors.forename: Lynn
authors.initials: L
authors.lastname: Landborg
authors.affiliation: Medtronic, Minneapolis, Minnesota.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Cerkvenik
authors.affiliation: Department of Radiology of Neuroradiology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.
authors.forename: Emanuel
authors.initials: E
authors.lastname: Kanal
mesh_terms: D000368:Aged; D002318:Cardiovascular Diseases / Q000175:diagnosis* / Q000453:epidemiology / Q000628:therapy*; D017147:Defibrillators, Implantable / Q000009:adverse effects; D004554:Electric Countershock / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D038622:Internationality; D008279:Magnetic Resonance Imaging / Q000009:adverse effects / Q000379:methods*; D008297:Male; D008875:Middle Aged
keywords: implantable cardioverter-defibrillator; magnetic resonance imaging