Echocardiographic assessment of myocardial infarction: comparison of a rat model in two strains

The purpose of this study was to induce myocardial infarction (MI) and compare the echocardiographic parameters and mortality ratio of Lewis inbred and Wistar outbred strain before and after the procedure to help choose the best one for MI studies. In this study MI was induced in 46 Lewis and 34 Wistar by occlusion of left anterior descending artery (LAD). Doppler, two-dimensional (2-D) and 2-D guided M-mode images were recorded from parasternal long-axis and parasternal short-axis and apical four-chamber views. The following parameters were acquired. Interventricular septum diastolic and systolic dimension (IVSd, s), diastolic and systolic left ventricular internal diameter (LVIDd, s), diastolic and systolic left ventricular posterior wall dimension (LVPWd, s), ejection fraction (EF), and fractional shortening (FS). The significant changes were observed in systolic IVS, LVID and EF and FS before and after MI and no significant difference was detected between Lewis and Wistar. The high mortality rate of 51% was seen in the procedure, including anesthesia in Lewis compared to 34% in Wistar. As a conclusion the echocardiographic parameters of these two strains were similar, but according to mortality rate and more cardiac anatomic variation in Lewis rats, Wistar is better for MI studies.