兔心肌心室间复极离散的电生理学机制研究

目的观察生理和缺血状态下兔心室间复极离散,探讨临床缺血心肌发生室性心律失常的电生理机制。方法酶解法急性分离兔心室肌细胞,采用细胞膜片钳技术,分别观察对照组(正常心室内膜动作电位时程)和缺血组(缺血心室内膜动作电位时程)在不同刺激频率下即基础循环周长(basic cycle length,BCL)=2000、1000、500及250 ms]左右心室肌心内膜细胞的动作电位时程变化。结果对照组生理心肌的室间离散分别为(47.70±7.89)ms,(45.50±7.00)ms,(40.30±7.33)ms,(37.90±6.45)ms;缺血后心室间离散则分别为(91.90±7.67)ms,(91.40±7.62)ms,(88.60±7.78)ms,(89.20±6.91)ms。结论生理状态的心肌左右心室间存在复极离散,缺血状态下心室间复极离散增大。这种心室间的复极异质性可能是缺血心肌发生室性心律失常的电生理机制之一。

Study of the electrophysiological mechanism of interventricular repolarization heterogeneity in rabbit

Objective To explore the electrophysiological mechanism of ventricular arrhythmia in clinical ischemic myocardium by observing the change of the interventricular repolarization heterogeneity in physiological and ischemic myocardium of rabbit.Methods Ventricular cardiomyocytes of rabbits were solated by enzymolysis.The patch-clamp was used to observe the change of endocardial action potential duration(APD) in control and ischemic groups through altering frequency of stimulation(basic cycle length,BCL=2 000 ms,1 000 ms,500 ms,250 ms).Results The interventricular dispersion was(47.70±7.89) ms,(45.50±7.00) ms,(40.30±7.33) ms and(37.90±6.45) ms respectively in normal physiological myocardium;it was(91.90±7.67) ms,(91.40±7.62) ms,(88.60±7.78) ms and(89.20±6.91) ms,respectively in ischemic state.Conclusion There is an interventricular repolarization heterogeneity between the left and right ventricles in physiological myocardium of rabbit and it enlarges in ischemia.It may be one of the electrophysiological mechanisms of ventricular arrhythmia in ischemic myocardium.