Journal of Arrhythmia (Feb 2016)

Measurement of diffuse ventricular fibrosis with myocardial T1 in patients with atrial fibrillation

  • Jay A. Montgomery, MD,
  • Wissam Abdallah, MD,
  • Zachary T. Yoneda, MD,
  • Evan Brittain, MD, MSCI,
  • Sam G. Aznaurov,
  • Babar Parvez, MD,
  • Keith Adkins, RN, MSN,
  • S. Patrick Whalen, MD,
  • J.C. Estrada, MD,
  • Sharon Shen, MD,
  • George H. Crossley, MD,
  • Arvindh Kanagasundram, MD,
  • Pablo Saavedra, MD,
  • Christopher R. Ellis, MD,
  • Mark Lawson, MD,
  • Dawood Darbar, MD,
  • M. Benjamin Shoemaker, MD, MSCI

DOI
https://doi.org/10.1016/j.joa.2015.08.005
Journal volume & issue
Vol. 32, no. 1
pp. 51 – 56

Abstract

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Background: Atrial fibrillation (AF) is associated with cardiac fibrosis, which can now be measured noninvasively using T1-mapping with cardiac magnetic resonance imaging (CMRI). This study aimed to assess the impact of AF on ventricular T1 at the time of CMRI. Methods: Subjects with AF scheduled for AF ablation underwent CMRI with standard electrocardiography gating and breath-hold protocols on a 1.5 T scanner with post-contrast ventricular T1 recorded from 6 regions of interest at the mid-ventricle. Baseline demographic, clinical, and imaging characteristics were examined using univariate and multivariable linear regression modeling for an association with myocardial T1. Results: One hundred fifty-seven patients were studied (32% women; median age, 61 years [interquartile range {IQR}, 55–67], 50% persistent AF [episodes>7 days or requiring electrical or pharmacologic cardioversion], 30% in AF at the time of the CMRI). The median global T1 was 404 ms (IQR, 381–428). AF at the time of CMRI was associated with a 4.4% shorter T1 (p=0.000) compared to sinus rhythm when adjusted for age, sex, persistent AF, body mass index, congestive heart failure, and renal dysfunction (estimated glomerular filtration rate<60). A post-hoc multivariate model adjusted for heart rate suggested that heart rate elevation (p=0.009) contributes to the reduction in T1 observed in patients with AF at the time of CMRI. No association between ventricular T1 and AF recurrence after ablation was demonstrated. Conclusion: AF at the time of CMRI was associated with lower post-contrast ventricular T1 compared with sinus rhythm. This effect was at least partly due to elevated heart rate. T1 was not associated with the recurrence of AF after ablation.

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