title: Noninvasive assessment of myocardial mechanics of the left ventricle in rabbits using velocity vector imaging.
abstract: BACKGROUND
  Our study aimed to investigate the feasibility of velocity vector imaging (VVI) to analyze left ventricular (LV) myocardial mechanics in rabbits at basal state.
  
  
  METHODS
  The animals used in this study were 30 New Zealand white rabbits. All rabbits underwent routine echocardiography under VVI-mode at basal state. The 2-dimensional (2-D) echocardiography images acquired included parasternal left long-axis views and short-axis views at the level of LV mitral valve, papillary muscles, and apex. Images were analyzed by VVI software.
  
  
  RESULTS
  At basal state, longitudinal LV velocity decreased from the basal to the apical segment (P<0.05). In the short axis direction, the highest peak myocardial velocity was found between the anterior septum and anterior wall for each segment at the same level; the peak strains and strain rates (SR) were the highest in the anterior and lateral wall compared to other segments (all P<0.05). During systole, LV base rotated in a clockwise direction and LV apex rotated in a counter-clockwise direction, while during diastole, both LV base and apex rotated in the direction opposite to systole. The rotation angle, rotation velocity and unwinding velocity in the apical segment were greater than the basal segment (P<0.05).
  
  
  CONCLUSIONS
  VVI is a reliable tool for evaluating LV myocardial mechanics in rabbits at basal state, and the LV long-axis short-axis and torsional motions reflect the normal regular patterns. Our study lays the foundation for future experimental approaches in rabbit models and for other applications related to the study of human myocardial mechanics.
authors.affiliation: Department of Ultrasound, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China (mainland).
authors.forename: Jia
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Department of Ultrasound, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China (mainland).
authors.forename: Da-Rong
authors.initials: DR
authors.lastname: Pu
authors.affiliation: Department of Ultrasound, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China (mainland).
authors.forename: Lei-Qi
authors.initials: LQ
authors.lastname: Tian
authors.affiliation: Department of Ultrasound, The First Affiliated Hospital of University of South China, Hengyang, Hunan, China (mainland).
authors.forename: Hai
authors.initials: H
authors.lastname: Tong
authors.affiliation: Department of Ultrasound, The First Affiliated Hospital of University of South China, Hengyang, Hunan, China (mainland).
authors.forename: Hong-Yu
authors.initials: HY
authors.lastname: Liu
authors.affiliation: Department of Ultrasound, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China (mainland).
authors.forename: Yan
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Department of Ultrasound, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China (mainland).
authors.forename: Qi-Chang
authors.initials: QC
authors.lastname: Zhou
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001783:Blood Flow Velocity / Q000502:physiology*; D004452:Echocardiography / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D011817:Rabbits; D016276:Ventricular Function / Q000502:physiology*