具有Mahaim纤维特性的左侧旁道电生理特征和射频消融

Electrophysiologicai characteristics and catheter ablation left-sided accessory pathways of Mahaim fiber

目的探讨具有Mahaim纤维特性的左侧旁道电生理特征和射频消融。方法28例经射频消融治疗具有Mahaim纤维特性的旁道，其中3例是具有Mahaim纤维特性的左侧旁道，均为男性，年龄分别为34、20、38岁，心动过速发作史1～5年。通过10极冠状窦电极导管、高位右房电极导管、房室束电极导管和消融导管记录其电生理检查结果、靶点位置，并观察体表心电图。结果窦性心律时心电图1例有轻微预激，2例正常；心房刺激出现与心动过速一致的宽QRS波（右束支阻滞或类似右束支阻滞），可见旁道前传文氏现象，室房逆传呈向心性递减传导，心动过速时房室束电图呈V．H．A顺序，逆传A波以房室束处最早，三磷酸腺苷可阻断旁道前传。窦性心律下，3例患者分别在左中后间隔、左后问隔、左前游离壁处放电消融阻断旁道。其中1例诊断为结室旁道，2例诊断为房束旁道。结论Mahaim纤维特性的左侧旁道极少见，有特殊的电生理特征，射频消融能治疗成功。

Objective To study electrophysiological characteristics and catheter ablation left-sided accessory pathways of Mabaim fiber. Methods Twenty-eight patients underwent catheter ablation for Mahaim fiber and3 patients was left-sided accessory pathways. All of them were male with 34,20,38 years old. The tachycardia history was 1-5 years. Electrophysiological characteristics,target sites and electrocardiogram （ECG, 12 leads） were recorded through catheter from coronary sinus （CS）,high right atrium （HRA）, His bundle and ablation. Results One patient＇s ECG showed little preexcitation, the other two were normal. Atrial stimulation could be easily induced tachycardia. Their ECG showed wide QRS waves （right bundle branch block or similar right bundle branch block）. The characteristics of accessory pathways were slow and anterograde decremental conduction as well as blocked by adenosine triphosphate injection. Ventricular-atrial conduction was via atrioventricular node with centripetal decreasing transmission during ventricular pacing. During tachycardia,the His bundle electrogram resulted in a V-H-A pattern, the retrograde A in His bundle was pioneer. The atriofascicular pathways of 2 patients were completely ablated respectively in left posterior lateral and before the free wall of mitral valve ring. The nodoventricular pathway of 1 patient was successfully ablated in left middle posterior lateral of mitral valve ring. Conclusions The left-sided accessory pathways of Mahaim fiber is an uncommon accessory pathway,which has specific electrophysiological characteristics. It is effective and safe to ablate accessory pathway with radiofrequency.