To explore the possible mechanism of Zhenyuan Fumai Granules in the treatment of chronic arrhythmia model rats.Methods:A total of 60 SD rats were randomly divided into blank group(n=10)and modeling group(n=50).The modeling group was injected with barium chloride solution through tail vein to establish arrhythmia model.A total of 46 model rats were randomly divided into model group(n=23)and intervention group(n=23).Among them, the rats in the intervention group were given intragastric administration of Zhenyuan Fumai Granules for 4 weeks, and the rats in the model group were given intragastric administration of the same volume of normal saline for 4 weeks.ECG indexes, SOD and MDA in peripheral blood, Na+-K+-ATP in heart tissue, as well as concentration changes of PI3K, AKT and p-AKT in heart tissue were compared in each group.Results:1)Compared with the model group, Zhenyuan Fumai Granules could significantly shorten the duration of arrhythmia(P<0.05), decrease the levels of MDA and Bax in peripheral blood, and increase the levels of SOD, PI3K, p-Akt and Bcl-2 as well as Na+-K+-ATP activity.The differences were statistically significant(P<0.05).Conclusion:Zhenyuan Fumai Granules can obviously antagonize arrhythmia and protect myocardial tissue, and its mechanism may be related to anti-oxygen free radicals and inhibition of cardiomyocyte apoptosis.