Abstract: Objective To observe the rule of variation myocardial damage in adriamycin-induced dilated cardiomyopathy (DCM ) in rabbit，and to determine the optimal time for further research. Methods Thrity-two rabbits were randomly assigned to control group(n=8) and model group (n=24). The DCM model was induced by adriamycin, 2 ml/kg body weight via ear vein for 8 weeks, the control group was given 2 ml/kg body weight of saline. Echocardiogram and hemodynamics parameters were assessed and plasma BNP was measuered at the 8th, 1 Oth and 12th week after the injections to model group ,and at 8th week to control group. Then the pathological change of the myocardium and microstructure were observed. Results The results of hemodynamics, ultrastructure and echocardiogram were coincident to the change of DCM. The myocardial damage occurred at 8th week in model group, and was most serious at 10th week, and lessened at 12th week (P＜0.05). Conclusions AT two weeks after the model established，the myocardial damage is most serious. It’s the optimal time for studying heart failure.

Key words: Adriamyc, Dilated cardiomyopathy, Myocardial damage, Animal model