title: Strain-rate imaging predicts the attenuation of left ventricular remodeling induced by ischemic postconditioning after myocardial infarction in mice.
abstract: BACKGROUND
  Systolic strain rate (SR) has been shown to correlate with the transmural extent of myocardial infarction (MI). Ischemic postconditioning (PC) decreases MI size. We aimed to determine whether SR may predict the reduction of left ventricular (LV) remodeling induced by PC in a murine model of ischemia-reperfusion.
  
  
  RESULTS
  C57BL6 mice underwent 60 minutes of left coronary artery occlusion followed by reperfusion. PC consisted of 3 cycles of 1 minute of reperfusion and 1 minute of ischemia performed immediately after reperfusion. After 24 hours of reperfusion, a first subset of mice was euthanized for determination of infarct size. An additional subset of mice underwent 3 months of reperfusion. Echocardiography and SR were serially assessed at baseline, 3 days, and 1, 2, 3 months after reperfusion. PC decreased the infarct size and increased SR values within infarcted segments as soon as 24 hours after reperfusion as compared with controls (14 ± 1 versus 6 ± 1 s(-1), P<0.001). Systolic SR was correlated with MI size assessed by the area of infarction/area at risk (r=-0.88, P<0.001). At 3 months, PC improved LV ejection fraction (55 ± 4 versus 45 ± 3%; P<0.05) and decreased LV dimensions as compared with controls. Strain rate at day 3 correlated with LV ejection fraction (0.75; P<0.001), end-systolic (r=-0.75; P=0.001), and end-diastolic volumes (r=-0.70; P<0.001) at month 3.
  
  
  CONCLUSIONS
  In this murine model of MI, SR accurately assessed the reduction in MI size induced by PC early after reperfusion and the subsequent reduction of LV remodeling.
authors: Université Claude Bernard Lyon I, France, U1060-CARMEN, Cardioprotection, Lyon, France.
authors: Hélène
authors: H
authors: Thibault
authors: Ludovic
authors: L
authors: Gomez
authors: Cyrille
authors: C
authors: Bergerot
authors: Lionel
authors: L
authors: Augeul
authors: Marielle
authors: M
authors: Scherrer-Crosbie
authors: Michel
authors: M
authors: Ovize
authors: Geneviève
authors: G
authors: Derumeaux
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009200:Myocardial Contraction; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy; D011237:Predictive Value of Tests; D020127:Recovery of Function / Q000502:physiology*; D013318:Stroke Volume; D013599:Systole; D016277:Ventricular Function, Left / Q000502:physiology*; D020257:Ventricular Remodeling / Q000502:physiology*