title: Measurement of diffuse ventricular fibrosis with myocardial T1 in patients with atrial fibrillation.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Vanderbilt University Medical Center, 1211 Medical Center Drive, Nashville, TN 37232, USA.
authors.forename: Jay A
authors.initials: JA
authors.lastname: Montgomery
authors.affiliation: Spectrum Health Medical Group, 2900 Bradford St NE, Grand Rapids, MI 49525, USA.
authors.forename: Wissam
authors.initials: W
authors.lastname: Abdallah
authors.affiliation: Vanderbilt University Medical Center, 1211 Medical Center Drive, Nashville, TN 37232, USA.
authors.forename: Zachary T
authors.initials: ZT
authors.lastname: Yoneda
authors.affiliation: Vanderbilt University Medical Center, 1211 Medical Center Drive, Nashville, TN 37232, USA.
authors.forename: Evan
authors.initials: E
authors.lastname: Brittain
authors.affiliation: Vanderbilt University Medical Center, 1211 Medical Center Drive, Nashville, TN 37232, USA.
authors.forename: Sam G
authors.initials: SG
authors.lastname: Aznaurov
authors.affiliation: Vanderbilt University Medical Center, 1211 Medical Center Drive, Nashville, TN 37232, USA.
authors.forename: Babar
authors.initials: B
authors.lastname: Parvez
authors.affiliation: Vanderbilt University Medical Center, 1211 Medical Center Drive, Nashville, TN 37232, USA.
authors.forename: Keith
authors.initials: K
authors.lastname: Adkins
authors.affiliation: Wake Forest Baptist Health Cardiology, 1 Medical Center Blvd, Winston-Salem, NC 27157, USA.
authors.forename: S Patrick
authors.initials: SP
authors.lastname: Whalen
authors.affiliation: Vanderbilt University Medical Center, 1211 Medical Center Drive, Nashville, TN 37232, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Estrada
authors.affiliation: Vanderbilt University Medical Center, 1211 Medical Center Drive, Nashville, TN 37232, USA.
authors.forename: Sharon
authors.initials: S
authors.lastname: Shen
authors.affiliation: Vanderbilt University Medical Center, 1211 Medical Center Drive, Nashville, TN 37232, USA.
authors.forename: George H
authors.initials: GH
authors.lastname: Crossley
authors.affiliation: Vanderbilt University Medical Center, 1211 Medical Center Drive, Nashville, TN 37232, USA.
authors.forename: Arvindh
authors.initials: A
authors.lastname: Kanagasundram
authors.affiliation: Vanderbilt University Medical Center, 1211 Medical Center Drive, Nashville, TN 37232, USA.
authors.forename: Pablo
authors.initials: P
authors.lastname: Saavedra
authors.affiliation: Vanderbilt University Medical Center, 1211 Medical Center Drive, Nashville, TN 37232, USA.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Ellis
authors.affiliation: Vanderbilt University Medical Center, 1211 Medical Center Drive, Nashville, TN 37232, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Lawson
authors.affiliation: Vanderbilt University Medical Center, 1211 Medical Center Drive, Nashville, TN 37232, USA.
authors.forename: Dawood
authors.initials: D
authors.lastname: Darbar
authors.affiliation: Vanderbilt University Medical Center, 1211 Medical Center Drive, Nashville, TN 37232, USA.
authors.forename: M Benjamin
authors.initials: MB
authors.lastname: Shoemaker
keywords: Atrial fibrillation; Atrial fibrillation ablation; Cardiac MRI; Myocardial T1; Ventricular T1