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目的 观察索他洛尔对兔在体心脏左心室壁各层心肌复极的影响 ,以证实在体心肌 M细胞的存在 ,探讨其与心律失常的关系。 方法 采用单相动作电位 (m onophasic action potential,MAP)记录技术 ,同步记录 12只开胸兔左心室外膜心肌 (epicardium ,Epi)、中层心肌 (m id- myocardium ,Mid)和心内膜心肌 (endocardium ,Endo)的 MAP,静脉注射索他洛尔后 ,测量 3层心肌 MAP的复极时限和跨心室壁心肌复极离散度 (transm ural dispersion of repolarization,TDR)。 结果 1用药前 Epi、Mid、Endo的 MAP10 0 %复极时限 (APD1 0 0 )分别为 (136± 16 )、(15 2± 19)、(15 0± 2 0 ) m s,TDR为 (17± 8) m s。每间隔 30 m in静脉注射索他洛尔 0 .5、1.0、1.5和 2 .0 m g· kg- 1后发现 ,索他洛尔剂量依赖性延长 3层心肌的 APD1 0 0 ,其中以延长 Mid的 APD1 0 0 更为明显 ,对 Epi和 Endo的 APD1 0 0 延长程度相近 ,使 TDR增加 ;至静脉注射 2 .0 mg· kg- 1 后 ,Epi、Mid、Endo的 APD1 0 0 分别为 (177± 30 )、(2 34± 32 )、(194± 30 ) ms,TDR为 (5 7± 15 ) ms(P <0 .0 5 ) ;2索他洛尔剂量依赖性地增加尖端扭转性室性心动过速 (torsade depointes,TDP)的发生率。 结论 在体兔心肌存在 M细胞。索他洛尔增加兔
Objective To observe the effect of sotalol on rabbit ventricular repolarization in the left ventricular wall in vivo to confirm the existence of M cells in the myocardium and to explore its relationship with arrhythmia. Methods The left ventricular epicardium (Epi), mid-myocardium (Mid) and endocardial myocardium of 12 open-chest rabbits were recorded synchronously with mopacity map (MAP) (MAP) of endocardium (Endocardium), and intravenous injection of sotalol, the repolarization time and transm ural dispersion of repolarization (TDR) of myocardium in 3-layer myocardium were measured. Results 1 The MAP 10 0% repolarization time (APD 1 0 0) of Epi, Mid and Endo before treatment were (136 ± 16), (15 2 ± 19) and (15 0 ± 20) ms, respectively 8) ms. After intravenous injection of sotalol 0.5, 1.0, 1.5 and 2.0 mg · kg-1 at intervals of 30 m, sotalol was found to prolong the APD1 0 0 of the 3-layer myocardium in a dose-dependent manner, with prolonged Mid APD1 0 0 was more obvious, and the TDP increased to a similar degree to APD1 0 0 in Epi and Endo. After the intravenous injection of 2.0 mg · kg -1, APD1 0 0 in Epi, Mid and Endo were (177 ± 20), (34 ± 32), (194 ± 30) ms, TDR was (57 ± 15) ms (P <0.05). 2 Sotalol dose-dependently increased the number of torsades de pointes The incidence of torsade depointes (TDP). Conclusion There are M cells in rabbit myocardium. Sotalol increases the rabbit