Full-Body MRI in Patients With an Implantable Cardioverter-Defibrillator: Primary Results of a Randomized Study.Citation: Journal of the American College of Cardiology. 65(24):2581-8, 2015 Jun 23.PMID: 25982014Institution: MedStar Washington Hospital CenterForm of publication: Journal ArticleSubject headings: *Cardiovascular Diseases/di [Diagnosis] | *Cardiovascular Diseases/th [Therapy] | *Defibrillators, Implantable | *Electric Countershock/mt [Methods] | *Internationality | *Magnetic Resonance Imaging/mt [Methods] | Aged | Cardiovascular Diseases/ep [Epidemiology] | Defibrillators, Implantable/ae [Adverse Effects] | Electric Countershock/ae [Adverse Effects] | Electric Countershock/is [Instrumentation] | Female | Follow-Up Studies | Humans | Magnetic Resonance Imaging/ae [Adverse Effects] | Male | Middle AgedLocal holdings: Available online from MWHC library: 1995 - present, Available in print through MWHC library:1999-2007ISSN:
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|Journal Article||MedStar Authors Catalog||Article||Available||25982014|
Available online from MWHC library: 1995 - present, Available in print through MWHC library:1999-2007
BACKGROUND: Magnetic resonance imaging (MRI) of patients with conventional implantable cardioverter-defibrillators (ICD) is contraindicated.
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).Copyright � 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.
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.
OBJECTIVES: 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.
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.