大鼠心脏缺血再灌注后发生复杂室性心律失常对左心室功能的影响

Effect of complex ventricular arrhythmia on left ventricular function in rats after reperfusion injury

目的探讨心脏缺血再灌注后发生复杂室性心律失常对左心室功能的影响。方法雄性(Sprague Dawley,SD)大鼠按随机数字表法分成3组:心肌梗死再灌注A组、延迟再灌注B组和假手术对照组,每组至少12只。观察并记录再灌注后及术后3 d内大鼠心律失常情况。术后3 d行超声检查评估大鼠左心室功能;Masson′s染色评估及TUNEL染色检测细胞凋亡。结果再灌注A组和延迟再灌注B组每搏射血量、射血分数、左心室内径缩短率和心排血量较对照组明显下降,差异有统计学意义(P<0.05)。复杂室性心律失常主要表现为室性期前收缩二联律或短阵室性心动过速。再灌注A组和延迟再灌注B组复杂室性心律失常发生率比较,差异无统计学意义[33%(4/12)vs.50%(6/12),P=0.41]。再灌注后并发室性心律失常可致左心室收缩功能进一步下降:收缩末直径和容积增加(P=0.004、P=0.005);每搏射血量、左心室射血分数、内径缩短率和心排血量均显著减低(P=0.038、P<0.001、P=0.001、P=0.01),差异均有统计学意义。Masson′s染色可见并发心律失常亚组大鼠心肌纤维断裂范围大且伴明显纤维化,TUNEL染色示细胞凋亡在再灌注并发室性心律失常亚组大鼠中均增多。结论心肌梗死再灌注后并发复杂室性心律失常可致左心室收缩功能进一步下降;同时伴有更加明显的心肌细胞萎缩、细胞凋亡和组织纤维化。

Objectives To explore the effect of complex ventricular arrhythmia on left ventricular function in rats after reperfusion injury.Methods Sprague Dawley rats were randomly divided into myocardial infarction reperfusion group,delayed reperfusion group and sham-operation group,each group had more than 12 rats.Electrocardiogram changes after reperfusion were observed and recorded.Left ventricular function changes were assessed by cardiac ultrasound at the third days after surgery;morphological and apoptosis changes were evaluated by Masson’s and TUNEL stain.Results Compared with sham group,stroke shot volume,left ventricular ejection fraction,fraction shortening and cardiac output decreased remarkably(P<0.05)in myocardial infantion group and delayed reperfusion group.Complex ventricular arrhythmias were mainly premature ventricular beats or burst ventricular tachycardia.There was no significant difference between myocardial infarction reperfusion group and delayed reperfusion group in the occurrence of complex arrhythmias[33%(4/12)vs.50%(6/12),P=0.41].Ventricular arrhythmia after reperfusion induced the decreasing of left ventricular systolic function:left ventricular systolic diameter and volume significantly increased(P=0.004,P=0.005);stroke shot,fraction shortening and cardiac output significantly reduced(P=0.038,P<0.001,P=0.001,P=0.01).Masson’s stain showed that the myocardial fiber rupture range was larger and the degree of fibrosis was more obvious in rats with ventricular arrhythmia after reperfusion.TUNEL stain indicated that apoptosis degree increased in rats with ventricular arrhythmia after reperfusion.Conclusions Reperfusion after myocardial infarction with complex ventricular arrhythmias stepwise deteriorate left ventricular systolic function,increase the fibrosis of myocardial tissue,induce the apoptosis of myocardial nucleus and cardiomyocyte atrophy.