美西律对兔楔形心肌动作电位时程、跨壁复极离散及索他洛尔口服后改变的影响

目的探讨美西律、索他洛尔、索他洛尔十美西律口服后对家兔左心室楔形心肌组织块电生理特性的影响。方法建立冠状动脉灌注的家兔左心室楔形心肌组织块模型。应用浮置玻璃微电极和心电图同步记录技术，观察美西律、索他洛尔、索他洛尔＋美西律口服后对家兔内外层心肌细胞的动作电位时程（APD）、跨壁复极离散（TDR）的影响。结果美西律组内、外膜心肌细胞的APD、Q—T间期及TDR在不同刺激周长下均较对照组缩短，索他洛尔组均较对照组延长，且以内膜延长为主（均P〈0．05），索他洛尔＋美西律组较对照组仅轻微延长，差异无统计学意义，但较索他洛尔组缩短（P〈005）。美西律组、索他洛尔＋美西律组心律失常发生率与对照组比较差异无统计学意义，索他洛尔组心律失常发生率高较对照组升高（P〈005）。，结论美西律可明显缩短内、外膜心肌细胞的APD、Q—T问期，并可减小心肌细胞的TDR。索他洛尔相反，抗心律失常同时容易导致心律失常，联合应用美西律可逆转索他洛尔对兔心肌电生理的不利作用，从而提高安全性。

The effect of Mexiletine on rabbit myocardial action potential duration,transmural dispersion of repolarization and the changes induced by Sotalol taken orally

Objective To investigate the effect of Mexiletine, Sotalol and Sotalol with Mexiletine on electrophysiological characteristics of rabbit left ventricle. Methods The effects of Mexiletine, Sotalol and Sotalol with Mexiletine taken orally on action potential duration （APD） and transmural dispersion of repolarization （TDR） of the epicardium and endocardium were observed by simultaneous recording with floating glass microelectrode and electrocardiogram in an established arterially perfused wedge of rabbit left ventricle. Results Under different stimulations, Q-T interval, APD and TDR of the epicardi- um and endocardium were significantly shortened in Mexiletine group, significantly prolonged in Sotalol group with much more in the endocardiumf P〈0.05）, and slightly prolonged in Mexiletine with Sotalol group（P〈0.05）, which was significantly shorter than Sotalol group. The rate of arrhythmia was significantly higher in Sotalol group （P〈0.05）, but not in Mexiletine group and Sotalol with Mexiletine group, compared to control group. Conclusion Mexiletine reduces, while Sotalol in- creases, APD,Q-T interval and TDR of the epicardium and endocardium. Sotalol has both anti-and pro-arrhythmia effects. Combined application of Mexiletine can reverse the adverse effects of Sotalol on myocardial electrophysiology of rabbit and increase its security.