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目的:检测慢性心力衰竭(CHF)大鼠心室肌钾电流的变化,探讨CHF时心律失常发生的可能机制。方法:建立腹主动脉缩窄大鼠CHF模型,采用全细胞膜片钳技术记录心室肌细胞短暂外向钾电流(Ito)、延迟整流性钾电流(IK)及内向整流性钾电流(IK1),并进行对照分析。结果:CHF组大鼠左心室收缩末压(LVSP)、左心室内压上升最大速率(+dp/dtmax)及左心室内压下降最大速率(-dp/dtmax)显著低于假手术组,左心室舒张末压(LVEDP)显著高于假手术组(均P<0.01),提示CHF模型制作成功。假手术组Ito的电流密度为(7.41±0.51)pA/pF,CHF组为(5.22±0.61)pA/pF,后者显著小于前者(P<0.01),Ⅰ～Ⅴ曲线显著下移;假手术组IK-tail的电流密度为(0.63±0.05)pA/pF,CHF组为(0.48±0.04)pA/pF,后者显著小于前者(P<0.01),Ⅰ～Ⅴ曲线显著下移;假手术组IK1内向电流密度为-(9.61±1.04)pA/pF,CHF组为-(6.33±0.71)pA/pF,后者显著小于前者(P<0.01),CHF组Ⅰ～Ⅴ曲线较假手术组显著上移。结论:CHF时,Ito、IK与IK1电流密度均显著减小,而IK和IK1减小可能是导致室性心律失常的重要原因。
Objective: To detect the change of potassium current in ventricular myocardium of chronic heart failure (CHF) rats and to explore the possible mechanism of arrhythmia in CHF. Methods: The rat model of aortic constriction was established. Whole-cell patch-clamp technique was used to record Ito, IK and IK1 in ventricular myocytes. Control analysis. Results: The left ventricular end-systolic pressure (LVSP), the maximum rate of left ventricular pressure increase (+ dp / dtmax) and the maximum rate of left ventricular pressure drop (-dp / dtmax) in CHF group were significantly lower than those in sham operation group Ventricular end-diastolic pressure (LVEDP) was significantly higher than that of sham operation group (all P <0.01), which suggested that CHF model was successfully made. The current density of Ito was (7.41 ± 0.51) pA / pF in sham operation group and (5.22 ± 0.61) pA / pF in CHF group, the latter was significantly lower than the former (P <0.01) The current density of IK-tail was (0.63 ± 0.05) pA / pF in CHF group and (0.48 ± 0.04) pA / pF in CHF group, which was significantly lower than the former (P <0.01) The inward current density of group IK1 was - (9.61 ± 1.04) pA / pF, and that of CHF group was - (6.33 ± 0.71) pA / pF, which was significantly lower than the former (P <0.01) Move up significantly. Conclusion: The current densities of Ito, IK and IK1 are significantly decreased in CHF patients, while the decrease of IK and IK1 may be the important causes of ventricular arrhythmia.