title: Multi-ethnic study of atherosclerosis: association between left atrial function using tissue tracking from cine MR imaging and myocardial fibrosis.
abstract: OBJECTIVE
  To investigate the association between left atrial ( LA left atrium ) function and left ventricular myocardial fibrosis using cardiac magnetic resonance (MR) imaging in a multi-ethnic population.
  
  
  METHODS
  For this HIPAA-compliant study, the institutional review board at each participating center approved the study protocol, and all participants provided informed consent. Of 2839 participants who had undergone cardiac MR in 2010-2012, 143 participants with myocardial scar determined with late gadolinium enhancement and 286 age-, sex-, and ethnicity-matched control participants were identified. LA left atrium volume, strain, and strain rate were analyzed by using multimodality tissue tracking from cine MR imaging. T1 mapping was applied to assess diffuse myocardial fibrosis. The association between LA left atrium parameters and myocardial fibrosis was evaluated with the Student t test and multivariable regression analysis.
  
  
  RESULTS
  The scar group had significantly higher minimum LA left atrium volume than the control group (mean, 22.0 ± 10.5 [standard deviation] vs 19.0 ± 7.8, P = .002) and lower LA left atrium ejection fraction (45.9 ± 10.7 vs 51.3 ± 8.7, P < .001), maximal LA left atrium strain ( Smax maximum LA strain ) (25.4 ± 10.7 vs 30.6 ± 10.6, P < .001) and maximum LA left atrium strain rate ( SRmax maximum LA strain rate ) (1.08 ± 0.45 vs 1.29 ± 0.51, P < .001), and lower absolute LA left atrium strain rate at early diastolic peak ( SRE LA strain rate at early diastolic peak ) (-0.77 ± 0.42 vs -1.01 ± 0.48, P < .001) and LA left atrium strain rate at atrial contraction peak ( SRA LA strain rate at atrial contraction peak ) (-1.50 ± 0.62 vs -1.78 ± 0.69, P < .001) than the control group. T1 time 12 minutes after contrast material injection was significantly associated with Smax maximum LA strain (β coefficient = 0.043, P = .013), SRmax maximum LA strain rate (β coefficient = 0.0025, P = .001), SRE LA strain rate at early diastolic peak (β coefficient = -0.0016, P = .027), and SRA LA strain rate at atrial contraction peak LA strain rate at atrial contraction peak (β coefficient -0.0028, P = .01) in the regression model. T1 time 25 minutes after contrast material injection was significantly associated with SRmax maximum LA strain rate (β coefficient = 0.0019, P = .016) and SRA LA strain rate at atrial contraction peak (β coefficient = -0.0022, P = .034).
  
  
  CONCLUSIONS
  Reduced LA left atrium regional and global function are related to both replacement and diffuse myocardial fibrosis processes. Clinical trial registration no.: NCT00005487
authors.affiliation: From the Division of Cardiology, Department of Medicine, Johns Hopkins University, 600 N Wolfe St, Blalock 524, Baltimore, MD 21287-0409 (M.I., B.A.V., S.S., S.D., A.C.A., J.A.C.L.); Department of Cardiology, Johns Hopkins Hospital, Baltimore, Md (M.H.); Cardiovascular Health Research Unit, Washington University, St Louis, Mo (S.R.H.); and Office of Biostatistics Research, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Md (C.O.W., D.A.B.).
authors.forename: Masamichi
authors.initials: M
authors.lastname: Imai
authors.forename: Bharath
authors.initials: B
authors.lastname: Ambale Venkatesh
authors.forename: Sanaz
authors.initials: S
authors.lastname: Samiei
authors.forename: Sirisha
authors.initials: S
authors.lastname: Donekal
authors.forename: Mohammadali
authors.initials: M
authors.lastname: Habibi
authors.forename: Anderson C
authors.initials: AC
authors.lastname: Armstrong
authors.forename: Susan R
authors.initials: SR
authors.lastname: Heckbert
authors.forename: Colin O
authors.initials: CO
authors.lastname: Wu
authors.forename: David A
authors.initials: DA
authors.lastname: Bluemke
authors.forename: João A C
authors.initials: JA
authors.lastname: Lima
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D050197:Atherosclerosis / Q000175:diagnosis* / Q000208:ethnology*; D016279:Atrial Function, Left; D003287:Contrast Media; D018450:Disease Progression; D005260:Female; D005355:Fibrosis / Q000473:pathology; D019786:Gadolinium DTPA; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology; D014481:United States
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA