To investigate the effect of Yiqi Huoxue Recipe (YHR

益气活血方) on the cardiac function and ultrastructure during the regression of myocardial hypertrophy induced by pressure overload in rats. The model of myocardial hypertrophy was established by abdominal aortic banding. Eighty male Wistar rats were divided into six groups

the normal control group I (n=20)

the normal control group II (n=12)

the hypertension model group I (n=12)

the hypertension model group II (n=12)

the YHR group (n=12) and the Captopril group (n=12). The observation was carried out in the normal control group I and the hypertension model group I after 4 weeks of modeling

and the other four groups were observed after 16 weeks of modeling (12 weeks of administration). The cardiac function was measured with a multichannel biological signal analysis system

and the myocardium ultrastructure was observed by a transmission electron microscope. (1) Compared with the normal control group I

the systolic blood pressure and cardiac coefficient (left ventricular weight/body weight) in the model I group was higher (P<0.05

P<0.01). (2) In the YHR group

cardiac coefficient and −dp/dtmax were lower

left ventricular systolic pressure and +dp/dtmin were higher when compared with the model group II and the Captopril group (P<0.05 or P<0.01). In the Captopril group

only cardiac coefficient was lower when compared with the mode group II (P<0.05). (3) Compared with the normal control group II

+dp/dtmax was higher (P<0.01) −dp/dtmax and isovolumetric contraction time (ICT) was lower (P<0.05

P<0.01) in both the YHR group and the Captopril group. (4) Results of the myocardium ultrastructure showed edema under myocardium plasmalemma

enlarged sarcoplasmic reticulum and T tube

and significantly enlarged intercalated disc of the cardiac muscle in the model groups. In the Captopril group

the extension of sarcoplasmic reticulum and T tube as well as the pathological changes of intercalated disc were lighter

with slight edema under the myocardium plasmalemma. In the YHR group

the expansion of the sarcoplasmic reticulum was less than in the Captopril group

part of the pathological changes of intercalated discs was slightly more severe than that in the Captopril group

the dissolution of nuclear chromatin was not found

which was similar to that of the Captopril group

and no injury of the nucleus was found

either. YHR could reverse myocardial hypertrophy in rats with abdominal aortic banding and improve the systolic and diastolic function of the left ventricle. The ultrastructure of the myocardium such as arcoplasmic reticulum

intercalated disc

and cell nucleus in abdominal aortic banding rats could be partly reversed by the recipe.