普罗帕酮对心室间复极异质性影响的电药理学机制研究

Study of the electropharmacological mechanism of effect of propafenone on interventricular repolarization heterogeneity

目的观察普罗帕酮对生理状态下兔心肌心室间复极异质性的影响,从动作电位时程(action potential dura- tion,APD)的角度探讨临床应用普罗帕酮治疗心律失常作用的电药理学机制。方法采用膜片钳技术,观察在不同刺激频率[即基础循环周长(basic cycle length,BCL)=2000、1000、500及250ms]下,不同浓度普罗帕酮(对照组,1μmol/L普罗帕酮组,6μmol/L普罗帕酮组,10μmol/L普罗帕酮组)对正常心肌左右心室内膜APD的影响。结果普罗帕酮由低浓度(1μmol/L)至超治疗浓度(10μmol/L)呈非浓度依赖性地减少室间离散;左右心室内膜APD和室间离散在不同浓度的普罗帕酮干预下仍呈慢频率依赖性特点(P＜0．05),且这种特点对普罗帕酮呈非浓度依赖性。结论生理状态的心肌左右心室间存在复极离散。普罗帕酮可减少这种复极异质性,这可能是其对无缺血心肌室性心律失常治疗作用的电药理学机制之一。

Objective To observe the effect and mechanism of propafenone on repolarization heterogeneity between two ventricles of rabbit in normal physiological state. Method Effect of propafenone at various concentrations on the APD of endocardium of ventricle in physiologyical state was observed with patch-clamp at varions stimulation frequencies. Results Pmpafenone decreased the repolarization dispersion between two ventricles independently of the concentration of propafenone from 1 μmol/L to 10 μmol/L. Both endocardium APD and interventricular dispersion showed characteristic of dependence on slow frequency when various concentmtions of pmpafenone were given （ P 〈 0.05）. This characteristic was independent of the concentration of propafenone. Conclusions There is heterogeneity of interventricular repolarization dispersion in normal physiological nisms of ity. It may be one of the electropharmacological mechatherapeutical effect of propafenone on ventricular arrhythmia in myocardium without ischemia.