【摘要】 目的探讨心肌动作电位动态变化在室颤机制中的作用。方法37只健康雄性3月龄大约克猪随机分为两组:22只猪结扎冠状动脉左前降支第一分支制备心肌梗死模型,15只同家系同月龄大约克猪入选对照组。4周后右室程序刺激猪的在体心肌,三层心肌针式复合电极记录刺激过程中陈旧性梗死心脏和正常结构心脏左室前壁心肌跨壁复极离散度(TDR),动作电位时程(APD)与舒张间期(DI)的动态变化等电生理参数。采用方差分析及q检验。结果心肌梗死4周后,陈旧性心梗组存活18只,其中12只诱发室颤,刺激周期为(190±5)ms;对照组全部存活,其中5只诱发室颤,刺激周期为(175±5)ms。两组间的差异有统计学意义[(190±5)ms vs(175±5)ms,P=0.001]。与正常心脏相比,陈旧性心梗组TDR显著增大[(15.66±4.45)ms vs(25.72±6.70)ms,P=0.001]。但是诱发室颤组与未诱发室颤组比较,两组TDR的差异无统计学意义[(20.43±7.01)ms vs(22.32±7.53)ms,P=0.45]。心肌APD恢复斜率最大值以及斜率大于1所占的比例从高到低依次为:陈旧性心梗诱发室颤组[MI+VF(+)组],假手术诱发颤动组[SO+ VF(+)组],假手术未能诱发颤动组[SO+VF(-)组],陈旧性心梗未能诱发颤动组[MI+VF (-)组]。结论APD恢复性质在室颤的维持机制中占有重要地位。APD恢复曲线越陡峭越容易发生室颤。TDR是心脏固有异质性的表现之一,对室颤的发生不具有明确的预测性。更多还原

【Abstract】 Objective Toinvestigate the role of dynamic dispersion of electrical recovery in ventricular fibrillation maintenance mechanism.Method Thirty-seren male Yorkshire pigs weighing (23±2.5) kg at 3 months age were randomly divided into Sham-operated group and myocardial infarction group in which the first branch of left anterior descending coronary artery of animals was hgated.After 4 weeks,according to VF occurrence by programmed electrical simulation,the myocardial infarction hearts were divided into two groups, twelve hearts in VF (+) group or six hearts in VF (-) group;and the normal hearts were divided into two groups,five hearts in VF (+) group or ten hearts in VF (-) group.Action potential duration (APD) of subendocardial,subepicardial and mid-layer myocardium of left ventricular anterior wall were recorded simultaneously.The relationship between APD and diastolic interval was quantified as an electrical restitution curve.A Student’s-test was used to specify differences between groups.Results At the fourth week after coronary artery ligation,eighteen myocardial infarction hearts and fifteen normal hearts were investigated.When investigating transmural dispersion of reporlarization (TDR) of left ventricle,there was no difference between VF (+) group and VF (-) group [ (20.43±7.01) ms vs (22.32±7.53) ms,P=0.45],although there was statistically significant between normal hearts and myocardial infarction hearts [ (15.66±4.45) ms vs (25.72±6.70) ms,P =0.001].The percentage of APD restitution slope exceed 1 and APD restitution slope maximum were high in the VF (+) group with myocardial infarction hearts and in the VF (+) group with normal hearts, lower in the the VF (-) with normal hearts and lowest in the the VF (-) group with myocardial infarction hearts.Conclusion Dynamic APD restitution properties may play an important role in the ventricular fibrillation maintenance mechanism.The APD restitution slope and not static TDR have prognostic value regarding ventricular fibrillation events.The hearts with the steepest of APD restitution curves has the greatest liability of ventricular fibrillation to happen.更多还原