Objective

2

To explore the mechanism of

Compound Qutan Huayu Formula

（祛痰化瘀中药复方， CQHF） in the treatment of atrial fibrillation （AF）.

Methods

2

Sixty male SD rats were randomly divided into blank group， model group， verapamil group， and low-， medium- and high-dose CQHF groups， with 10 rats in each group. Except for the blank group， the rats were injected with acetylcholine （Ach， 66 μg/ml）-calcium chloride （CaCl

2

， 10 mg/ml） mixture through tail vein for 7 days to establish the AF rat model. From the second day of modeling， the rats in the high-， medium-， and low-dose CQHF groups were given 41.25， 20.63， and 10.31 g/（kg·d） of CQHF by gavage， respectively， while those in the verapamil group were given 25 mg/（kg·d） of verapamil solution by gavage， and those in the blank group and the model group were administered with 8.93 ml/（kg·d） of normal saline by gavage， all treated for two weeks. Twelve hours after the last intragastric administration， the electrocardiogram in lead Ⅱ of the limbs was recorded， and the duration of AF was monitored. The changes of myocardial ultrastructure of the rats in each group were observed under transmission electron microscope. Contents of advanced oxidation protein products （AOPP）， malondialde-hyde （MDA）， reactive oxygen species （ROS） and superoxide dismutase （SOD） in serum were detected by ELISA.

Results

2

The rats in the blank group had a normal electrocardiogram， and the sarcomere of the atrial myocytes were intact and clear， with normal mitochondrial structure. Compared to those in the blank group， the ECG of the rats in the model group showed AF rhythm， while serum AOPP， MDA， ROS levels increased， and SOD level decreased （

P

＜0.05 or

P

＜0.01）； moreover， the sarcomere of atrial myocytes was broken， with discontinuous “Z” band， disordered arrangement， blurred “I” band， and swollen and increased mitochondria. Compared to those in the model group， the AF duration of the rats in each treatment group was significantly reduced； serum AOPP， ROS， and MDA levels in the low-， medium- and high-dose

CQHF groups increased （

P

＜0.05 or

P

＜ 0.01）； serum AOPP and ROS levels in the verapamil group decreased， while the SOD level increased （

P

＜0.05）； the sarcomere of the atrial myocytes of the rats in the high- and medium-dose CQHF groups were slightly broken， with relatively neat arrangement， slightly swollen and increased mitochondria， and relatively complete structure， while the myocardial ultrasonography in the low-dose CQHF group was not significantly improved.

Conclusion

2

CQHF can shorten the AF duration and improve myocardial injury. The mechanism may be related to the inhibition of oxidative stress， and the effect is better in terms of the medium- and high-dose CQHF.