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目的 观察胺碘酮和索他洛尔对家兔跨左心室壁不同部位心肌细胞电生理特性的影响 ,从组织水平探讨两种药物致尖端扭转性室性心动过速 (torsadedepointes,TdP)发生率不同的原因。方法 采用标准玻璃微电极记录技术 ,记录心外膜心肌、中层心肌和心内膜心肌的跨膜动作电位 (trans membranceactionpotential,TAP)。在不同基础周长 (basiccyclelength ,BCL)刺激下 (2 50～ 2 0 0 0ms) ,分别观察 0 3～ 3 0 μmol·L- 1 浓度的胺碘酮和 1 0～ 1 0 0 μmol·L- 1 浓度的索他洛尔对 3种心肌TAP的影响。结果 胺碘酮频率依赖性和浓度依赖性地延长 3种心肌的动作电位时限 (actionpotentialduration ,APD90 ) ,由于 3种心肌的APD90 延长程度近似 ,用药后跨心室壁复极离散度 (transmuraldispersionofre polarization ,TDR)无明显增加。索他洛尔呈逆频率依赖性和浓度依赖性地延长 3种心肌的APD90 ,与心外膜心肌和心内膜心肌相比 ,中层心肌的APD90 延长更明显 ,使TDR明显增加 ,且随着剂量的增加这种作用更为显著。在 2 0 0 0msBCL刺激时 ,1 0 0 μmol·L- 1 浓度的索他洛尔诱发早期后除极 (earlyafterde polarization ,EAD) ,胺碘酮无此作用。 结论 胺碘酮和索他洛尔对跨心室壁不同部位心肌细胞电生理特性产生不同的
Objective To investigate the effects of amiodarone and sotalol on the electrophysiological properties of myocardial cells in different parts of the rabbit trans-left ventricular wall. The incidence of torsadedepointes (TdP) Different reasons. Methods Standard glass microelectrode recording technique was used to record transmembrane action potential (TAP) of epicardial myocardium, middle myocardium and endocardial myocardium. Amiodarone at concentrations of 0 3 ~ 300 μmol·L-1 and 10 μmol·L -1 -100 μmol·L-1 were observed under basic cyclelength (BCL) stimulation (2 50 ~ 2 0 0 ms) 1 concentration of sotalol on three kinds of myocardial TAP. Results Amiodarone prolonged the action potential duration (APD90) of 3 kinds of myocardium in a dose-dependent manner and in a concentration-dependent manner. Due to the similar degree of APD90 extension in 3 kinds of myocardium, transmural dispersion of polarization (TDR ) No significant increase. Sotalol increased APD90 in three kinds of myocardium in a frequency-dependent and concentration-dependent manner. Compared with epicardial and endocardial myocardium, APD90 prolongation in the middle myocardium was more pronounced and TDR increased significantly This effect is more pronounced with dose increases. Soxantrone at a concentration of 100 μmol·L-1 induced early afterdepolarization (EAD) at 20 0 ms BCL without amiodarone. Conclusions Amiodarone and sotalol produce different electrophysiological characteristics of myocardial cells in different parts of the transmural wall