Objective: To explore the electrophysiological effects of Erxian decoction on ovariextomized rat heart. Method: Thirty-two female healthy rats were randomly divided into four groups:sham operated control group

ovariectomized group

estrogen group

and Erxian decoction group. The rats in estrogen group and Erxian decoction group were intragastrically administrated with estradiol valerate (0.2 mg · kg-1 · d-1) and Erxian decoction (7.5 g · kg-1 · d-1) respectively

ig

for 12 weeks. The rats in sham operated control group and ovariectomized group were intragastrically administrated of with equivalent volume of purified water for 12 weeks. The Ⅱ lead ECGs of anesthetic rats were recorded. And the spontaneous activities of left ventricular outflow tract and the fast action potentials (APs) of left ventricular muscle were also recorded by intracellular electrode. Result: Compared with sham operated control group

P

R and T amplitude decreased notably

and P duration

PR interval

QT interval

and T duration decreased significantly in ovariectomized group (P<0.05

P<0.01). In estrogen group

T amplitude

P duration

PR interval and QT interval were reversed to control group. In Erxian decoction group

R amplitude

T amplitude

P duration and PR interval were reversed to control group. Compared with control group

the pacemaker rates of ventricular outflow tract and norepinephrine(NE) induced abnormal pacemaker activities increased significantly in ovariectomized group. In estrogen and Erxian decoction groups

the pacemaker activities of ventricular outflow tract decreased were markedly compared with lower than ovariectomized group

and NE-induced spontaneous arrhythmia was significantly relieved. That is

estrogen and er-xian decoction depressed the activity of latent pacemaker cell in ventricular outflow tract and had less possibility to lead to arrhythmia. Compared with control group

action potential duration (APD) was shortened significantly in ovariectomized group

especially APD50. Compared with ovariectomized group

APD50 was significantly prolonged in estrogen group and Erxian decoction group and restored to control group (P<0.05

P<0.01). Conclusion: Erxian decoction could significantly improve the electrophysiological activities of hearts of ovariectomized rats

heart and has a certain effect in relieving arrhythmia caused by estrogen reduction.