冠脉内应用氨甲酰胆碱对心室复极的影响

目的探讨氨甲酰胆碱对完整动物心脏心室复极的影响。方法在4只绵羊冠状动脉回旋支内分别注入1.0 mol.L-1和2.5 mol.L-1的氨甲酰胆碱,注射时间3m in。记录回旋支支配区域心外膜心电图,测量心室的激动-恢复间期(AR I)以代表心室复极时间。静脉给予一氧化氮合成抑制剂(L-精氨酸20 mg.kg-1)后,再次冠脉内给予2.5 mol.L-1的氨甲酰胆碱。结果回旋支内灌注1.0 mol.L-1和2.5 mol.L-1的氨甲酰胆碱导致其支配区域心外膜心电图心室激动-恢复间期分别延长(38±17)m s和(58±14)m s(P<0.05)。氨甲酰胆碱所致的心室激动-恢复间期延长被L-精氨酸所阻断。结论冠脉内注射氨甲酰胆碱延长心室激动-恢复间期或心室复极时间,内源性一氧化氮很可能介导氨甲酰胆碱心室复极的影响。

Effect of intracoronary carbachol administration on ventricular repolarisation in a sheep model

Aim To investigate the effect of carbachol on ventricular repolarization in an intact animal heart.Methods In 4 sheep,carbachol was injected to the left circumflex coronary artery(LCX) at 1.0 mol·L~(-1) and 2.5 mol·L~(-1) respectively.Multiple unipolar ECGs were acquired from the epicardium of the LCX territory.Activation-recovery interval(ARI) was analysed from these ECGs.Administration with 2.5 mol·L~(-1) was also repeated after pre-treatment with nitro-L-arginine(20 mg·kg~(-1)),a nitric oxide synthase inhibitor.Results Intracoronary injection with carbachol at 1.0 mol·L~(-1) or 2.5 mol·L~(-1) increased ARI by(38±17) ms and(58±14) ms,respectively(P<0.05).ARI prolongation at 2.5 mol·L~(-1) was prevented by pre-treatment with nitro-L-arginine.Conclusions Carbachol results in a dose-dependent prolongation in ventricular repolarization in this open-chest animal model.This effect is largely mediated by endogenous nitric oxide.