低钾及索他洛尔对形成心电图U波的实验观察  

Experimental observation on genesis of U wave in ECG in rabbits

作　　者：李运田[1] 张存泰[1] 陆再英 

机构地区：[1]武汉同济医科大学附属同济医院心内科,430030

出　　处：《中华心血管病杂志》2000年第2期124-127,共4页Chinese Journal of Cardiology

基　　金：卫生部科研基金课题!(9820 95)

摘　　要：目的　探讨在体兔心电图U波的产生机制。方法　采用单相动作电位 (MAP)记录技术 ,同步记录 18只开胸兔左室心外膜心肌 (epicardium ,Epi)、中层心肌 (mid myocardium ,Mid)、心内膜心肌 (endocardium ,Endo)的MAP。复制低钾动物模型或静脉注射索他洛尔 ,在心电图上出现U波后 ,同步测量QU间期 ,Epi、Mid和Endo的动作电位复极时程 (APD10 0 ) ,并观察它们之间的关系。结果　 (1)用药前体表心电图上无U波 ,低钾或静脉注射索他洛尔 1 5mg/kg和 2 0mg/kg后 ,心电图上出现U波并逐渐增大 ;(2 )U波出现后 ,Epi和Endo的APD10 0 均在U波的起点之前 ,而Mid的APD10 0 与QU间期一致 ;(3)当三层心肌中的任何一层心肌的MAP上出现早期后除极时 ,U波较无早期后除极时增大 ;当所有三层心肌的MAP上均出现早期后除极时 ,U波最为明显。结论　在体兔心电图的U波起源于Mid ,早期后除极可使U波增大。Objective To investigate the genesis of U wave in rabbits in vivo. Methods With the monophasic action potential (MAP) recording technique, MAPs of epicardium (Epi), mid myocardium (Mid) and endocardium (Endo) were recorded simultaneously by specially designed plunge needle electrodes across the left ventricular myocardium in 18 open chest rabbits. Animal models of acute hypokalemia were reproduced or sotalol was injected intravenously with different doses. After U wave developed, QU interval, action potential duration at 100% repolarization (APD 100 ) in Epi, Mid and Endo were measured, and the relationships among them were observed. Results 1. After acute hypokalemia or 1 5 mg/kg and 2 0 mg/kg of sotalol were used, U wave emerged and progressively enlarged. 2. After U wave had appeared, APD 100 in Epi and Endo was prior to starting point of U wave, while APD 100 in Mid was consistent with QU interval. 3. When early after depolarization (EAD) appeared on MAP of any of the three myocardial layers, U wave was more obvious than that without EAD. When EADs occurred on MAPs of all three myocardial layers, U wave was the most predominant. Conclusion It is suggested that U wave is originated form mid myocardium, and EAD might make it enlarged in rabbits in vivo.

关 键 词：低钾血症 索他洛尔 动作电位 心电描记术 

分 类 号：R96[医药卫生—药理学]