title: Left atrial flow velocity distribution and flow coherence using four-dimensional FLOW MRI: a pilot study investigating the impact of age and Pre- and Postintervention atrial fibrillation on atrial hemodynamics.
abstract: OBJECTIVE
  To use four-dimensional (4D) flow MRI to characterize and quantify 3D blood flow in the left atria (LA) of patients with a history of atrial fibrillation (AF).
  
  
  METHODS
  The 4D flow MRI was acquired in 19 volunteers (n = 9<30 years, n = 10>50 years) and 10 patients with AF (62 ± 9.6 years; n = 4 in persistent AF, n = 6 postintervention). The LA in each dataset was segmented, and intra-atrial blood flow velocity was quantified. Flow coherence was measured as the consistency of the net blood flow vector.
  
  
  RESULTS
  Quantification of atrial flow revealed significant differences in atrial hemodynamics between age groups. Postintervention AF patients had a mean blood flow of 0.22 ± 0.04 m/s, which was not significantly different than age-matched volunteers (0.21 ± 0.03 m/s). Patients with persistent AF had a mean blood flow of 0.13 ± 0.01 m/s, lower than AF patients in sinus rhythm (0.22 ± 0.04 m/s, P = 0.005), or age-matched volunteers (0.21 ± 0.03 m/s, P < 0.001). Flow coherence was significantly impaired in patients in AF.
  
  
  CONCLUSIONS
  Flow-sensitive MRI shows that patients with a history of AF had global hemodynamics in the LA similar to those of age-matched volunteers. Additional studies with larger cohorts of AF patients and correlation with outcome are needed to further investigate the potential of atrial 4D flow MRI to flow patterns indicative of stroke risk in AF.
authors.affiliation: Department of Radiology, Northwestern Memorial Hospital, Chicago, Illinois, USA. jacob.fluckiger@northwestern.edu
authors.forename: Jacob U
authors.initials: JU
authors.lastname: Fluckiger
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Goldberger
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Lee
authors.forename: Jason
authors.initials: J
authors.lastname: Ng
authors.forename: Richard
authors.initials: R
authors.lastname: Lee
authors.forename: Amita
authors.initials: A
authors.lastname: Goyal
authors.forename: Michael
authors.initials: M
authors.lastname: Markl
mesh_terms: D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology*; D001783:Blood Flow Velocity / Q000187:drug effects; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D005260:Female; D006325:Heart Atria / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
chemical_list: D000889:Anti-Arrhythmia Agents
keywords: 4D flow MRI; atrial fibrillation; cardiac magnetic resonance; flow imaging; flow quantification