Effect of Zhigancao Decoction on Atrial Monophasic Action Potential in Rabbits

Objective: To observe the effect of Zhigancao Decoction(ZD)on left atrial(LA)monophasic action potential(MAP)in rabbits,and to explore its possible anti-arrhythmia mechanism.Methods: Twelve rabbits were equally randomized into model group and ZD group,which were given intragastric administration of ZD and normal saline,respectively.The monophasic action potential recording and S1S1 electric stimulation techniques were used to investigate the change of rabbit atrial MAP in the two groups and MAP in ZD group under different stimulation frequency.Results: Compared with the model group,atrial monophasic action potential amplitude(MAPA) was decreased,and monophasic action potential duration(MAPD)20,50,and 90 were prolonged in ZD group(P 0.05).Under different stimulation frequency,MAPD of ZD group was prolonged(P 0.05),and the effect was weakened with the decrease of stimulation frequency(P 0.05).Conclusion: ZD can reduce rabbit atrial MAPA,and prolong the MAPD in frequency-dependent manner,which maybe contribute to its safe anti-arrhythmia effect.