title: Quantitative assessment of regional myocardial function in mice by tissue Doppler imaging: comparison with hemodynamics and sonomicrometry.
abstract: BACKGROUND
  Tissue Doppler imaging (TDI) is a novel echocardiographic method to quantify regional myocardial function. The objective of this study was to assess whether myocardial velocities and strain rate (SR) could be obtained by TDI in mice and whether these indices accurately quantified alterations in left ventricular (LV) systolic function.
  
  
  RESULTS
  TDI was performed in 10 healthy mice to measure endocardial (v(endo)) and epicardial systolic velocities and SR. In further experiments, TDI indices were compared with dP/dt(max) and with sonomicrometer-derived regional velocities, at rest and after administration of dobutamine or esmolol. TDI indices were also studied serially in 8 mice before and 4 and 7 hours after endotoxin challenge. Myocardial velocities and SR were obtained in all mice with low measurement variability. TDI indices increased with administration of dobutamine (v(endo) from 2.2+/-0.3 to 3.8+/-0.2 cm/s [P<0.01]; SR from 12+/-2 to 20+/-2 s(-1) [P<0.05]) and decreased with administration of esmolol (v(endo) 1.4+/-0.2 cm/s [P<0.05]; SR 6+/-1 s(-1) [P<0.01]). Both indices correlated strongly with dP/dt(max) (r2=0.79 for SR and r2= 0.69 for v(endo); both P<0.0001). SR and shortening fraction were predictors of dP/dt(max) even after adjustment for the confounding effect of the other variables. V(endo) correlated closely with sonomicrometer-measured velocity (r2=0.71, P<0.0005). After endotoxin challenge, decreases in both v(endo) and SR were detected before decreases in shortening fraction became manifest.
  
  
  CONCLUSIONS
  Myocardial velocities and SR can be measured noninvasively in mice with the use of TDI. Both indices are sensitive markers for quantifying LV global and regional function in mice.
authors.affiliation: Cardiac Ultrasound Laboratory in the Cardiology Division of the Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Mas 02114, USA.
authors.forename: Igal A
authors.initials: IA
authors.lastname: Sebag
authors.forename: Mark D
authors.initials: MD
authors.lastname: Handschumacher
authors.forename: Fumito
authors.initials: F
authors.lastname: Ichinose
authors.forename: John G
authors.initials: JG
authors.lastname: Morgan
authors.forename: Ryuji
authors.initials: R
authors.lastname: Hataishi
authors.forename: Ana Clara T
authors.initials: AC
authors.lastname: Rodrigues
authors.forename: J Luis
authors.initials: JL
authors.lastname: Guerrero
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Steudel
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Raher
authors.forename: Elkan F
authors.initials: EF
authors.lastname: Halpern
authors.forename: Geneviève
authors.initials: G
authors.lastname: Derumeaux
authors.forename: Kenneth D
authors.initials: KD
authors.lastname: Bloch
authors.forename: Michael H
authors.initials: MH
authors.lastname: Picard
authors.forename: Marielle
authors.initials: M
authors.lastname: Scherrer-Crosbie
mesh_terms: D000818:Animals; D002316:Cardiotonic Agents / Q000494:pharmacology; D004280:Dobutamine / Q000494:pharmacology; D015150:Echocardiography, Doppler / Q000379:methods / Q000592:standards; D004731:Endotoxins / Q000494:pharmacology; D006334:Heart Function Tests; D006339:Heart Rate; D007700:Kinetics; D051379:Mice; D009068:Movement; D011412:Propanolamines / Q000494:pharmacology; D015203:Reproducibility of Results; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis*
chemical_list: D002316:Cardiotonic Agents; D004731:Endotoxins; D011412:Propanolamines; D004280:Dobutamine; C036604:esmolol