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J Am Coll Cardiol. 2015 Jun 23;65(24):2581-2588. doi: 10.1016/j.jacc.2015.04.047. Epub 2015 May 14.

Full-Body MRI in Patients With an Implantable Cardioverter-Defibrillator: Primary Results of a Randomized Study.

Author information

1
Division of Cardiology, Medical University of South Carolina, Charleston, South Carolina. Electronic address: goldmr@musc.edu.
2
Department of Diagnostic and Interventional Radiology and Nuclear Medicine, German Red Cross Hospital, Neuwied, Germany.
3
Department of CMR, University Hospital Lausanne, Lausanne, Switzerland.
4
Prince Sultan Cardiac Center, Riyadh, Saudi Arabia.
5
Central Coast Cardiology, Salinas, California.
6
Heart Center Semmelweis University, Budapest, Hungary.
7
United Heart and Vascular Clinic, Minneapolis, Minnesota.
8
Sentara Norfolk General Hospital, Norfolk, Virginia.
9
Washington Hospital Center, Washington, DC.
10
Medtronic, Minneapolis, Minnesota.
11
Department of Radiology of Neuroradiology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.

Abstract

BACKGROUND:

Magnetic resonance imaging (MRI) of patients with conventional implantable cardioverter-defibrillators (ICD) is contraindicated.

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.

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).

KEYWORDS:

implantable cardioverter-defibrillator; magnetic resonance imaging

PMID:
25982014
DOI:
10.1016/j.jacc.2015.04.047
[Indexed for MEDLINE]
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