OBJECTIVE: To observe the impact of total flavonoids from Ganshanbian(Herba Hyperici Attenuati)on the expression of vascular smooth muscle membrane L-type calcium channel alpha1 C subunit(CaL-α1C) and ATP-sensitive K+channel(KATP)-Kir6.1mRNA, and explore the mechanisms of the antiarrhythmic effect of Ganshanbian(Herba Hyperici Attenuati)total flavonoids.METHODS: The treatment group was fed total flavonoids from Ganshanbian(Herba Hyperici Attenuati)for 7 days by gavage with 100 mg·kg﹣1·d﹣1.The blank control group and model control group were given the same amount of normal saline for 7 d.Arrhythmias were induced by performing a myocardial ischemia-reperfusion and electrocardiogram was observed. Reverse transcription-polymerase chain reaction was used to detect the expression of CaL-α1CandKATP-Kir6.1 mRNA in the myocardial cell membrane of all groups of rats. RESULTS: Total flavonoids from Ganshanbian(Herba Hyperici Attenuati) can delay the appearance of myocardial ischemia reperfusion arrhythmias,shorten the duration of myocardial ischemia reperfusion arrhythmias, reduce heart rate, reduce cell membrane expression of CaL-α1C mRNA and enhance the expression of KATP-Kir6.1 mRNAin myocardial ischemia-reperfusion arrhythmic rats.CONCLUSION: Total flavonoids from Ganshanbian(Herba Hyperici Attenuati) can alleviate arrhythmias by affecting the expression of L-type calcium channels and ATP-sensitiveK+ channels.