Objective To study the effect and mechanism of Qishen Yiqi Dropping Pill [dropping pills of Huangqi（Radix Astragali） and Danshen（Radix et Rhizoma Salviae Miltiorrhizae） for reinforcing qi] on the left ventricular structure and cardiac function in rats with myocardial infarction（MI）.Methods The successfully made MI model rats were randomized into control group and Qishen Yiqi Dropping Pill group（treatment group） with 15 in each

and a sham-operation group was set up with 15 models.The treatment group was administered Qishen Yiqi Dropping Pill 38mg/（kg·d）-1 by gavage

and the other two groups were given the same volume of normal saline.Eight weeks later

hemodynamic and ultrasonic cardiogram examinations were performed to observe the infarction size

myocardial angiotensin Ⅱ（Ang Ⅱ） level

myocardial apoptosis index（AI）

myocardial bcl-2 and bax protein expression

etc.

and morphological analysis on myocardium was done with light microscope and transmission electron microscope.Results In the control group

the left ventricle mass index （LVMI）

interventricular septal thickness（IVST）

left ventricular posterior wall thickness（LVPWT）

left ventricle end-diastolic pressure（LVEDP）

and infarction size were all worse than those of the sham-operation group（P<0.05 or P<0.01）. In the treatment group

the LVMI

IVST

LVPWT

infarction size

LVEDP

Ang Ⅱ level

and AI were all less than those of the control group（P<0.05 or P<0.01）

and the myocardial bcl-2 protein expression was stronger than that of the control group（P<0.05）

while the Bax protein expression was weaker than that of the control group（P<0.05）.The morphological analysis showed that the myocardial damage in the treatment group was significantly minor than that of the control group.Conclusion Qishen Yiqi Dropping Pill can relieve the left ventricular remodeling and improve the cardiac function in rats with myocardial infarction

possibly relating to its decreasing Ang Ⅱ level

regulating myocardial bcl-2 and Bax protein expression

and alleviating myocardial apoptosis.