title: Assessment of longitudinal tissue Doppler imaging of the left ventricular septum and free wall as an indicator of left ventricular systolic function in dogs.
abstract: OBJECTIVE
  To evaluate tissue Doppler imaging (TDI) of the left ventricular (LV) free wall (FW) and ventricular septum (VS) as an indicator of LV systolic function in dogs.
  
  
  METHODS
  7 healthy Beagles.
  
  
  METHODS
  Doses of dobutamine (5 and 10 microg/kg/min) and esmolol (50 and 100 microg/kg/min) were infused into the LV of each dog. With each dose, heart rate; myocardial performance index (MPI); transmitral inflow and ejection time (determined via pulsed-wave Doppler [PWD] echocardiography); and FW and VS velocities of the mitral valve annulus (determined via TDI during systole [S'], early diastole [E'], and late diastole [A']) were assessed.
  
  
  RESULTS
  With each dose, dobutamine significantly increased heart rate and the first derivatives of LV pressure (+dP/dt and -dP/dt), whereas esmolol significantly decreased the +dP/dt and -dP/dt values, compared with baseline. Esmolol (100 microg/kg/min) significantly decreased the VS-TDI-derived S' velocity and FW-TDI-derived E' velocity; dobutamine significantly increased transmitral inflow and TDI velocities. Regression coefficient between VS-TDI-derived S' velocity and +dP/dt was higher than that between FW-TDI-derived S' velocity and +dP/dt. Compared with baseline, the PWD- and VS-TDI-derived MPI were significantly decreased by dobutamine and significantly increased by esmolol at each dose. Values of FW-TDI-derived MPI were higher than values derived via the other techniques. Correlation between +dP/dt and VS-TDI-derived MPI was greater than that between +dP/dt and FW-TDI- or PWD-derived MPI.
  
  
  CONCLUSIONS
  In healthy dogs, the VS-TDI-derived S' velocity and MPI appear to be reliable assessments for evaluating LV systolic function.
authors.affiliation: Department of Small Animal Internal Medicine, School of Veterinary Medicine, Kitasato University, 23-35-1 Higashi, Towada, Aomori 034-8628, Japan.
authors.forename: Yasutomo
authors.initials: Y
authors.lastname: Hori
authors.forename: Shingo
authors.initials: S
authors.lastname: Sato
authors.forename: Fumio
authors.initials: F
authors.lastname: Hoshi
authors.forename: Sei-ichi
authors.initials: S
authors.lastname: Higuchi
mesh_terms: D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D000818:Animals; D004280:Dobutamine; D004285:Dogs / Q000502:physiology*; D015150:Echocardiography, Doppler / Q000379:methods* / Q000662:veterinary; D011412:Propanolamines; D013599:Systole / Q000187:drug effects / Q000502:physiology*; D016277:Ventricular Function, Left / Q000187:drug effects / Q000502:physiology*
chemical_list: D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D004280:Dobutamine; C036604:esmolol