title: Time-course changes in left ventricular myocardial deformation in STZ-induced rabbits on velocity vector imaging.
abstract: OBJECTIVE
  To clarify the time-course changes in left ventricular myocardial deformation using velocity vector imaging and to provide insights into our understanding of the cardiac pathophysiology in diabetes mellitus.
  
  
  METHODS
  Thirty New Zealand white rabbits were randomly divided into either the control group (n = 10) or the diabetes mellitus (DM) group (induced with STZ, n = 20). For the myocardial deformation studies, echocardiography and syngo-vector velocity imaging (VVI) were performed at baseline and after 2, 4, 8, and 12 weeks in all of the rabbits. The left ventricular (LV) global longitudinal and circumferential strain and strain rate were measured. For histomorphological study of the heart structure, 2 of the STZ-induced rabbits were killed at 2, 4, 8, and 12 weeks. Routine hematoxylin and eosin staining was performed.
  
  
  RESULTS
  At 2 weeks, the global longitudinal strain (GLS), systolic strain rate (GLSRs), and diastolic strain rate (GLSRd) were significantly lower in the DM group compared with the control group (-18.16% versus -24.00%, -1.86 s(-1) versus -2.49 s(-1), 1.93 s(-1) versus 2.42 s(-1), respectively, P < 0.05), while, compared with the control group, the global circumferential strain (GCS), systolic strain rate (GCSRs), and diastolic strain rate (GCSRd) in the DM group were significantly decreased (-12.77% versus -23.31%, -1.31 s(-1) versus -2.20 s(-1), 1.41 s(-1) versus 2.15 s(-1), respectively, P < 0.05) at 8 weeks. With the progression of untreated diabetes, the histoanatomical alterations intensified gradually beginning at 2 weeks.
  
  
  CONCLUSIONS
  The progressive impairments in LV myocardial deformation and structure occurred early in diabetic rabbits with normal LV ejection fraction (EF), FS, and E/A. VVI could be used to evaluate subtle cardiac dysfunction in the early phase of DM.
authors.forename: Shi
authors.initials: S
authors.lastname: Zeng
authors.forename: Tao
authors.initials: T
authors.lastname: Jiang
authors.affiliation: Department of Ultrasonography, the Second Xiangya Hospital, Central South University, No,139 Middle Renmin Road, Changsha, Hunan 410011, P,R, China. hnzqc2013@163.com.
authors.forename: Qi-Chang
authors.initials: QC
authors.lastname: Zhou
authors.forename: Lianghui
authors.initials: L
authors.lastname: Yuan
authors.forename: Jia-Wei
authors.initials: JW
authors.lastname: Zhou
authors.forename: Dan-Min
authors.initials: DM
authors.lastname: Cao
mesh_terms: D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000150:complications* / Q000503:physiopathology; D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000503:physiopathology; D058065:Diabetic Cardiomyopathies / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003971:Diastole / Q000502:physiology; D004195:Disease Models, Animal; D004452:Echocardiography / Q000379:methods* / Q000706:statistics & numerical data; D015588:Observer Variation; D011817:Rabbits; D011897:Random Allocation; D013599:Systole / Q000502:physiology; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000209:etiology* / Q000503:physiopathology