title: Interstitial fibrosis, left ventricular remodeling, and myocardial mechanical behavior in a population-based multiethnic cohort: the Multi-Ethnic Study of Atherosclerosis (MESA) study.
abstract: BACKGROUND
  Tagged cardiac magnetic resonance provides detailed information on regional myocardial function and mechanical behavior. T1 mapping by cardiac magnetic resonance allows noninvasive quantification of myocardial extracellular expansion (ECE), which has been related to interstitial fibrosis in previous clinical and subclinical studies. We assessed sex-associated differences in the relation of ECE to left ventricular (LV) remodeling and myocardial systolic and diastolic deformation in a large community-based multiethnic population.
  
  
  RESULTS
  Midventricular midwall peak circumferential shortening and early diastolic strain rate and LV torsion and torsional recoil rate were determined using cardiac magnetic resonance tagging. Midventricular short-axis T1 maps were acquired in the same examination pre- and postcontrast injection using Modified Look-Locker Inversion-Recovery sequence. Multivariable linear regression (estimated regression coefficient, B) was used to adjust for risk factors and subclinical disease measures. Of 1230 participants, 114 had a visible myocardial scar by late gadolinium enhancement. Participants without a visible myocardial scar (n=1116) had no history of previous clinical events. In the latter group, multivariable linear regression demonstrated that lower postcontrast T1 times, reflecting greater ECE, were associated with lower circumferential shortening (B=-0.1; P=0.0001), lower LV end-diastolic volume index (B=0.6; P=0.0001), and lower LV end-diastolic mass index (B=0.4; P=0.0001). In addition, lower postcontrast T1 times were associated with lower early diastolic strain rate (B=0.01; P=0.03) in women only and lower LV torsion (B=0.005; P=0.03) and lower LV ejection fraction (B=0.2, P=0.01) in men only.
  
  
  CONCLUSIONS
  Greater ECE is associated with reduced LV end-diastolic volume index and LV end-diastolic mass index in a large multiethnic population without history of previous cardiovascular events. In addition, greater ECE is associated with reduced circumferential shortening, lower early diastolic strain rate, and a preserved ejection fraction in women, whereas in men, greater ECE is associated with greater LV dysfunction manifested as reduced circumferential shortening, reduced LV torsion, and reduced ejection fraction.
authors.affiliation: Department of Cardiology, Johns Hopkins University, Baltimore, MD.
authors.forename: Sirisha
authors.initials: S
authors.lastname: Donekal
authors.forename: Bharath A
authors.initials: BA
authors.lastname: Venkatesh
authors.forename: Yuan Chang
authors.initials: YC
authors.lastname: Liu
authors.forename: Chia-Ying
authors.initials: CY
authors.lastname: Liu
authors.forename: Kihei
authors.initials: K
authors.lastname: Yoneyama
authors.forename: Colin O
authors.initials: CO
authors.lastname: Wu
authors.forename: Marcelo
authors.initials: M
authors.lastname: Nacif
authors.forename: Antoinette S
authors.initials: AS
authors.lastname: Gomes
authors.forename: W Gregory
authors.initials: WG
authors.lastname: Hundley
authors.forename: David A
authors.initials: DA
authors.lastname: Bluemke
authors.forename: Joao A C
authors.initials: JA
authors.lastname: Lima
mesh_terms: D000368:Aged; D050197:Atherosclerosis / Q000175:diagnosis* / Q000208:ethnology / Q000503:physiopathology; D018450:Disease Progression; D005006:Ethnicity; D005260:Female; D005355:Fibrosis / Q000175:diagnosis / Q000208:ethnology / Q000503:physiopathology; D006331:Heart Diseases / Q000175:diagnosis* / Q000208:ethnology / Q000503:physiopathology; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D009200:Myocardial Contraction / Q000502:physiology*; D009206:Myocardium / Q000473:pathology; D011159:Population Surveillance / Q000379:methods*; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D013318:Stroke Volume; D014481:United States / Q000453:epidemiology; D016277:Ventricular Function, Left / Q000502:physiology; D020257:Ventricular Remodeling
keywords: LV torsion; T1 mapping; circumferential strain; expressed sequence tags; interstitial myocardial fibrosis; tagging