目的研究定心方（DX）对大鼠实验性心律失常的影响。方法采用尾静脉注射乌头碱诱发心律失常、冠脉结扎诱发心肌缺血及再灌注损伤性心律失常、股静脉注射氯化钙诱发心律失常。结果在乌头碱诱发心律失常实验中，与空白对照组比较，美西律组、DX大、小剂量组的心律失常出现时间延后，持续时间缩短（P＜0．05或0.01）。心肌缺血及再灌记注损伤性心律失常发生率，空白组100％，DX大剂量组25％，两组比较P＜0．01，其抗心律失常作用可能与DX调整NE、DA、5－HT等有关。在氯化钙诱发心律失常中，除DX大、小剂量组各2例未出现外，其余在2min内均出规定性扑动或间动，且多在8min内死亡，死亡率，空白组100％，DX大剂量组50％，两组比较P＜0．05。结论DX对以上快速型心律失常有良好的拮抗作用。 Objective To study the effect of DXX on experimental arrhythmia in rats. Methods Aconitine was injected into caudal vein to induce arrhythmia, myocardial ischemia and reperfusion injury were induced by coronary ligation, and arrhythmia was induced by intravenous injection of calcium chloride in femoral vein. Results Compared with the control group, the arrhythmia induced by aconitine in the mexiletine group and the large and small doses of DX delayed the duration and shortened the duration (P <0.05 or 0.01). The incidence of arrhythmia after myocardial ischemia and reperfusion was 100% in the blank group and 25% in the DX high-dose group. The anti-arrhythmic effects of the two groups were possibly related to the changes of NE, DA, 5 -HT and so on. In the calcium chloride-induced arrhythmias, except for the DX large and small dose group, 2 cases did not appear, the rest within 2min were given a predetermined flutter or intermaxillary, and more than 8min death, mortality, blank group 100 %, DX high dose group 50%, P <0.05. Conclusion DX has a good antagonism of the above tachyarrhythmia.