Objective      To compare the method for establishing

rabbit acute myocardial infarction (AMI) models by ligating different branches of coronary arteries.     Methods      Thirty New Zealand white rabbits were randomly divided into two groups with their left anterior descending branch ligated (LAD group) or their left ventricular branch ligated (LVB group). The animals underwent ECG and their creatinase level was measured before and 30 min

24 h and 1 week after ligation. The animals received myocardial contrast echocardiography (MCE) before and 24 h and 1 week after ligation followed by coronary arteriography

and their hemodynamic indications were detected 1 week after ligation. The animals were sacrificed and left ventricular tissue samples were taken for the measurement of the infarct size (IS) with triphenyltetrazolium chloride (TTC) staining.     Results      The ST segment on ECG of the two groups was significantly elevated 30 min after ligation

declined significantly in LAD group 24 h after ligation（P0.05）and more significantly 1 week after ligation（P0.01）. Coronary arteriography showed that 81.8% and 100% of middle coronary artery segment were occluded in LAD group and LVB group

respectively

1 week after ligation（P0.05）. The systolic blood pressure (SBP)

diastolic blood pressure (DBP)

maximal elevation and decline rates of left ventricular pressure (LVEDP)

±dp/dt

max

and ejection factor (EF) in both groups were significantly lower while the left ventricular end-diastolic dimension (LVEDD) was significantly higher in LVB group than in LAD group 1 week after ligation than before ligation（P0.05）. TTC staining showed that the IS was smaller in LAD group than in LVB group（P0.05）and the variance of A×β was positively correlated with the ±dp/dt

max

and IS（r=0.62

0.55

and 0.80

P0.05）.     Conclusion      The infarct size is ideal

stable and reliable in the rabbit AMI model established by ligating the LVB

and can thus be used in observation of AMI during long-term follow-up. The rabbit AMI model established by ligating the LAD is more

suitable for observing acute reperfusion and collateral circulation.