摘要
目的室性心律失常是临床常见急诊,长QT综合征(LQTS)所致的尖端扭转型室性心动过速(TdP)是室性心律失常的一种类型。为进一步研究长QT综合征,特制作离体LQT2兔心脏模型。方法新西兰兔共12只,取出心脏,立即行逆行主动脉灌注,然后用有齿镊钳夹房室结造成Ⅲ度房室传导阻滞,分别用1000ms刺激周长(CLs)起搏至少100个心动周期,体表心电图提示无ST-T明显压低或抬高,给予低钾低镁台氏液灌流5min,观察EAD及心律失常情况。然后用加有右旋索他洛尔(d-Sotalol)100μmol/L浓度的台氏液逆行Langendorff灌流30min后再分别用上述刺激周期进行刺激,观察:①90%动作电位时程(APD90);②90%复极时间(RT90);③跨室壁复极离散度(TDR);④早期后去极化(EAD)及尖端扭转型室性心动过速的发生率;⑤平均QT间期等的变化。结果12只新西兰离体Langendorff灌流兔心脏,在心动过缓及高浓度d-Sotalol(100μmol/L)存在时,动作电位时程明显延长,TDR明显增加(P<0.001),并诱发出EAD(11/12,91.67%),但TdP发生率低(3/12,25%),在附加的低钾低镁台氏液灌流时,TdP发生率高(10/12,83.33%)。结论d-sotalol可在Langendroff灌流离体新西兰兔心脏上成功制备LQT2模型。
Objective To mimic the inherited LQT2 in isolated rabbit hearts. Methods With the monopasic action potential （MAP） recording technique and volume -conducted 12 -lead ECG, left ventricular epicardium and endocardium MAPs and volume - conducted 12 - lead ECGs were recorded simutaneously. EAD and TdP were induced by means of bradycardia in the presence of high concentration of d - sotalol （100uM/L） and shortly after lowing the concentration of potassium and magnesium in the perfusate. Results （1） D- sotalol increased action potential duration and transmural dispersion of repolarization （TDR） in isolated rabbit hearts. （2）Early afterdepolarization （EAD） was induced by means of bradycardia in the presence of high concentration of d- sotalol （10^-4M） in 11 of 12 （91.67%） rabbit hearts, in which the torsade de pointes （TdP） was induced in 3 rabbit hearts （25%）. （3）After lowing the concentration of potassium and magnesium of the perfusate, the incidence of TdP increased to 10 of 12（ 83.33% ）. Conclusion D - sotalol mainly increases the APD90, TDR, induces EAD and mimics the LQT2 in isolated rabbit hearts
出处
《医学研究杂志》
2008年第6期31-35,共5页
Journal of Medical Research
基金
温州市科技局基金资助项目(Y20060091)
