Objective To study the effect of Pingl? Formula (PL) on the arrhythmia of myocardial ischemia-reperfusion in rats.Methods Rat arrhythmia models were established by occlusion of the LAD coronary artery for 15 min and thereafter reperfusion for 45 min.At the same time,the changes were observed on lead Ⅱ dynamic ECG.The activities of Ca~(2+)-ATPase,Mg~(2+)-ATPase,and Na~+,K~+-ATPase were determined, respectively.The levels of ATP,total adenine nucleotides(TAN),and energy charge(EC) of the myocardial organized energy state were analyzed by RP-HPLC.Results PL(ig 0.04,0.20,and 1.00 g/kg) showed to decrease the incidence of arrhythmia induced by ischemia-reperfusion,shorten the duration of ventricular arrhythmia and eliminate the incidence of ventricular fibrillation.The activities of Ca~(2+)-ATPase,Mg~(2+)-ATPase,and Na~+,K~+-ATPase were increased by PL.In the PL(0.04,0.20,and 1.00 g/kg) groups,ATP levels recovered to 58%,68%,and 86% as compared with normal group,simul-taneously,TAN values were enhanced to 25%,49%,and 66% and EC values to 24%,27%,and 29%, respectively.Conclusion PL has obvious antiarrhythmic effect on rat,the protective action is related to the improvement of energy metabolism.