title: Quantitative assessment of regional peak myocardial acceleration during isovolumic contraction and relaxation times by tissue Doppler imaging.
abstract: OBJECTIVE
  To examine regional wall acceleration and its relation to relaxation.
  
  
  METHODS
  8 sheep were examined by tissue Doppler ultrasound imaging (VingMed Vivid FiVe) in apical four chamber views to evaluate the left ventricular wall divided into six segments and the mitral annulus in two segments. Peak myocardial acceleration during isovolumic periods (pIVA) derived from tissue Doppler echocardiography was analysed during isovolumic contraction (ICT) and relaxation times (IRT) in each segment.
  
  
  METHODS
  After scanning at baseline, haemodynamic status was changed by administration of blood, dobutamine, and metoprolol. Changes of pIVA during IRT and ICT were compared over the four haemodynamic conditions in parallel with their peak positive and negative dP/dt measured with a high frequency manometer tipped catheter.
  
  
  RESULTS
  pIVA of the basal lateral segment during ICT correlated most strongly with peak positive dP/dt (r = 0.96, p < 0.0001) and there was good correlation between pIVA of the mitral valve annulus in the septum during IRT and peak negative dP/dt (r = 0.80, p < 0.0001). pIVA differed significantly between the four haemodynamic conditions during ICT in all segments (p < 0.05); pIVA during IRT did not differ significantly between the four conditions.
  
  
  CONCLUSIONS
  pIVA of the basal lateral wall during ICT correlated most strongly with peak positive dP/dt, and pIVA of the septal mitral valve annulus during IRT correlated well with peak negative dP/dt.
authors.affiliation: L608, Pediatric Cardiology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239-3098, USA. sahnd@ohsu.edu.
authors.forename: I
authors.initials: I
authors.lastname: Hashimoto
authors.forename: X-K
authors.initials: XK
authors.lastname: Li
authors.forename: A Hejmadi
authors.initials: AH
authors.lastname: Bhat
authors.forename: M
authors.initials: M
authors.lastname: Jones
authors.forename: D J
authors.initials: DJ
authors.lastname: Sahn
mesh_terms: D000818:Animals; D002302:Cardiac Output / Q000187:drug effects; D002316:Cardiotonic Agents / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology; D018618:Echocardiography, Doppler, Color; D005240:Feasibility Studies; D006334:Heart Function Tests / Q000379:methods*; D006439:Hemodynamics / Q000502:physiology; D008790:Metoprolol / Q000494:pharmacology; D009200:Myocardial Contraction / Q000502:physiology*; D012756:Sheep; D016277:Ventricular Function, Left / Q000502:physiology*
chemical_list: D002316:Cardiotonic Agents; D008790:Metoprolol; D004298:Dopamine