title: Longitudinal study of cardiac remodelling in rabbits following infarction.
abstract: BACKGROUND
  Cardiac remodelling following myocardial infarction (MI) is a complex, dynamic process. There have been few longitudinal studies of these changes.
  
  
  METHODS
  A 2-dimensional transthoracic echocardiography was performed on 20 rabbits, before and 1, 2, 4, 8, and 12 weeks after MI (n = 14) and twice for controls (n = 6). Chronic left ventricular (LV) infarct size was histologically characterized and correlated with mechanical function. A linear mixed model was used to analyze longitudinal and infarct size-related changes in LV end-systolic volume (ESV), end-diastolic volume (EDV), ejection fraction (EF), sphericity, circumferential strain, and wall motion score index.
  
  
  RESULTS
  Mean LV infarct size was 28.9% ± 9.3%. After MI, rapid remodelling occurred in LVESV, LVEF, and sphericity for 2 weeks and LVEDV for 4 weeks, with slower changes afterwards. LV infarct size correlated with LVESV (r = 0.76), LVEDV (r = 0.71), and LVEF (r = 0.69). Larger infarcts resulted in greater LVESV dilation (P = 0.04) and faster LVEDV (P < 0.01), LVEF (P < 0.01), and sphericity (P < 0.01) remodelling. Apical global circumferential strain and wall motion score index increased for 1 week, then stabilized, regardless of infarct size, and apical global circumferential strain was correlated with apical infarction (r = 0.58). Additionally, regional circumferential strain decreased in segments with severe (> 80%) infarction more quickly (P < 0.01) and by a greater degree (P = 0.04) compared with segments with minor (< 20%) infarction.
  
  
  CONCLUSIONS
  The most dynamic remodelling of cardiac function in this model occurred during the first 4 weeks, stabilizing thereafter, with changes maintained up to 12 weeks. Infarct size affected both the early rate and long-term extent of mechanical remodelling.
authors.affiliation: Department of Molecular Cardiology, Cleveland Clinic, Cleveland, Ohio 44195, USA.
authors.forename: Yves T
authors.initials: YT
authors.lastname: Wang
authors.forename: Zoran B
authors.initials: ZB
authors.lastname: Popović
authors.forename: Igor R
authors.initials: IR
authors.lastname: Efimov
authors.forename: Yuanna
authors.initials: Y
authors.lastname: Cheng
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004452:Echocardiography; D006321:Heart / Q000503:physiopathology*; D008137:Longitudinal Studies; D008297:Male; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011817:Rabbits; D020257:Ventricular Remodeling / Q000502:physiology*