title: [Research of myocardial velocity characteristics of paced canine heart based on ultrasonic Doppler tissue imaging].
abstract: OBJECTIVE
  To quantitatively analyze the characteristics of regional myocardial velocities of paced heart over His bundle, and explore the myocardial velocity pattern.
  
  
  METHODS
  5 dogs were paced at 120 times/min over His bundle. We defined the His bundle adjacent region and the top region of interventricular septum (IVS) as our regions of interest (ROI). Images of Doppler tissue velocity in ROI and corresponding electrocardiograms were observed and recorded by a 2-D Color Doppler tissue imaging (DTI) system. Quantitative velocities of myocardial DTI images were mapped by a neural network from the image sequences. Finally the velocity characteristics of the myocardium around His bundle and IVS were analyzed.
  
  
  RESULTS
  We obtained myocardial time-velocity curves in the ROI, and some results based on those curves: In the His bundle adjacent region intervals of myocardial systole and diastole were (209.75 +/- 19.41) ms and (294.50 +/- 17.87) ms, respectively. Myocardial systole velocity (S), early diastole velocity (E) and late diastole velocity (A) were (5.43 +/- 1.53) cm/s, (3.95 +/- 1.18) cm/s and (1.72 +/- 0.77) cm/s, respectively, E/A was 2.06 +/- 0.95; In IVS region intervals of myocardial systole and diastole were (191.33 +/- 17.23) ms and (294.70 +/- 17.91) ms, respectively. S, E and A were (3.17 +/- 1.34) cm/s, (2.17 +/- 0.64) cm/s and (1.48 +/- 0.52) cm/s, respectively. E/A was 1.305 +/- 0.287.
  
  
  CONCLUSIONS
  The primary characteristics of myocardial velocities paced over His bundle were: 1) Myocardial velocities in His bundle adjacent region were higher than those in IVS. 2) E/A was greater than one.
authors.forename: Quan-hui
authors.initials: QH
authors.lastname: Huang
authors.forename: Tian-fu
authors.initials: TF
authors.lastname: Wang
authors.forename: De-yu
authors.initials: DY
authors.lastname: Li
authors.forename: Chang-qiong
authors.initials: CQ
authors.lastname: Zheng
authors.forename: Li-xue
authors.initials: LX
authors.lastname: Yin
authors.forename: Yi
authors.initials: Y
authors.lastname: Zheng
mesh_terms: D000818:Animals; D002036:Bundle of His / Q000502:physiology*; D002304:Cardiac Pacing, Artificial; D003971:Diastole / Q000502:physiology; D004285:Dogs; D018618:Echocardiography, Doppler, Color; D006346:Heart Septum / Q000000981:diagnostic imaging*; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D007091:Image Processing, Computer-Assisted; D016571:Neural Networks, Computer; D013599:Systole / Q000502:physiology