Serial echocardiographic assessment of left ventricular dimensions and function after myocardial infarction in mice

Objective: To test the usage of serial echocardiography in mice with induce d myocardial infarct (MI) and to characterize the mouse model of MI. Method s: C57 mice underwent open-chest surgery to induce left coronary artery occ lusion or sham-operation (SH). Echocardiography was performed before and at 1, 2.5, 6 and 9 weeks after surgery. Left ventricular end diastolic and en d systolic dimensions (LVEDd, LVESd) and fractional shortening (FS) were me asured. Haemodynamics was determined at week 9 by LV catheterization and he arts were examined morphologically. Results: Post-infarct mortality was 46% (10/22), of which, 70% died of acute heart failure or LV rupture within th e first week. LV dimensions and FS remained stable in SH group (n=10) durin g the study period. In surviving MI mice (n=12), there was modest LV dilata tion and fall in FS at week 1. Compared with week 0 values, there were prog ressive increase in LVEDd (+50 similar to+66%) and LVESd (+124 similar to+1 71%), and decline in FS (-53 similar to-73%) during the 2.5 similar to 9 we ek period. Infarcted mice also had lower LV systolic pressure (LVSP), dP/dt (max) and dP/dt(min) (all P<0.01 vs. SH group). Infarct size, LVSP and dP/d t significantly correlated with FS and LV dimensions (r=0.61 similar to 0.8 0, all P<0.01). Conclusions: LV remodeling and dysfunction in mice with MI are time-dependent processes and early remodeling seems associated with hig h risk of rupture and acute pump failure. Our findings provide a baseline d escription of this murine model and confirm echocardiography as a reliable means to serially assess changes of cardiac structure and function after MI . (C) 2000 Elsevier Science B.V. All rights reserved.