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 induced myocardial infarct (MI) and to characterize the mouse model of MI. METHODS C57 mice underwent open-chest surgery to induce left coronary artery occlusion or sham-operation (SH). Echocardiography was performed before and at 1, 2.5, 6 and 9 weeks after surgery. Left ventricular end diastolic and end systolic dimensions (LVEDd, LVESd) and fractional shortening (FS) were measured. Haemodynamics was determined at week 9 by LV catheterization and hearts were examined morphologically. RESULTS Post-infarct mortality was 46% (10/22), of which, 70% died of acute heart failure or LV rupture within the first week. LV dimensions and FS remained stable in SH group (n = 10) during the study period. In surviving MI mice (n = 12), there was modest LV dilatation and fall in FS at week 1. Compared with week 0 values, there were progressive increase in LVEDd (+50(-)+66%) and LVESd (+124(-)+171%), and decline in FS (-53(-)-73%) during the 2.5-9 week period. Infarcted mice also had lower LV systolic pressure (LVSP), dP/dtmax and dP/dtmin (all P < 0.01 vs. SH group). Infarct size, LVSP and dP/dt significantly correlated with FS and LV dimensions (r = 0.61-0.80, all P < 0.01). CONCLUSIONS LV remodeling and dysfunction in mice with MI are time-dependent processes and early remodeling seems associated with high risk of rupture and acute pump failure. Our findings provide a baseline description of this murine model and confirm echocardiography as a reliable means to serially assess changes of cardiac structure and function after MI.