射频导管消融心肌梗死后浦肯野纤维参与的室性心动过速

Radiofrequency catheter ablation of Purkinje system involved ventricular tachycardia after myocardial infarction

目的报道心肌梗死（MI）后浦肯野纤维参与室性心动过速（VT）的电生理机制和射频导管消融。方法3例男性患者，55—75岁，前壁MI经抗心律失常药物和／或血运重建治疗后，仍反复发作VT／室性早搏（PVC），呈右束支阻滞（RBBB）图形伴心电轴左偏或右偏。左心室射血分数0．44～0．61。应用Carto电解剖标测系统引导盐水灌注射频导管标测和消融VT／PVc。结果例1和例2程序性心室刺激反复诱发出持续性临床VT，例3术中自发非持续性临床Vrr／频发PVC。3例VT的标测结果均不符合典型MI后瘢痕折返性VT，均在VT／PVC时，在后间隔低电压区边缘标测到最早浦肯野电位（PP）或舒张期电位（DP）提前体表QRS波-20—-70ms处消融VT／PVC成功。结论MI后可以发生浦肯野纤维参与的单形性VT，可以发生在MI后急性缺血时期，也可发生在MI后远期，其电生理特性、标测和射频导管消融与特发性左心室分支性VT相近，射频导管消融可有效根除或控制此类VT。

Objective To investigate the mechanism and radiofrequency catheter ablation of ventricu- lar tachycardia （VT） arising from the left posterior Purkinje fibers in patients with a prior myocardial infarction （MI）. Methods Three patients were all male s, and aged 55 to 75 years old, with recurrent episodes of VT after anterior MI [ left ventricular ejection fraction （LVEF） 0.44 -0. 61 ~ despite antiarrhythmic drugs and/or revascularization therapy. The VT or premature ventricular contractions （PVC） presented right bundle branch block （RBBB） with left axis or right axis deviation. Carto electroanatomic mapping system and saline irrigated radiofrequency catheter were used for mapping and ablating of VT/PVC. Results Clinical sustained VT was reproducibly induced by programmed stimulation in 2 patients, and spontaneous clinical non-sustained VT/PVC were observed in 1 patient. Purkinje potentials （PP） or diastolic potentials （DP） were sequentially observed along the left ventricular posterior septum adjacent to the low voltage area during the VT/PVC in all the 3 patients. The typical macro-reentrant VT around the MI scar could not be mapped in anyone of the 3 patients. Radiofrequency energy delivered at the site exhibiting a PP/DP-QRS interval of -20 to -70 ms successfully eliminated the VT/PVC. Conclusion Purkinje system involved monomorphic VT after MI,which is analogous to idiopathic left VT, can develop in the acute or chronic phase of MI. Radiofrequency catheter ablation can effectively eliminate this VT without affecting left ventricular conduction.