希氏-浦肯野系统电冲动与实验性室性心律失常的关系

以针电极探查 2 5只犬心脏希氏 浦肯野系统 (HPS)的电冲动 ,观察其与缺血和再灌注室性心律失常的关系。结果表明自发室性心律失常的最早激动点 ,其双极电图以Q波为起始 ,源于HPS者HPS电位在前 ,源于心肌者HPS电位在后。自发HPS电冲动未向周边传出时 ,仅见局部电图异常 ;向周边传出时 ,则触发或驱动室性早搏、单形与多形室性心动过速和心室颤动。心室颤动初期心脏电图有序 ,终末期心室电冲动分离 ,而HPS电冲动频率最快 ,提示起关键驱动作用。室性心律失常体表QRS波窄者提示起源于HPS或经HPS快速传导 ,QRS波宽者多起源于心肌 ,也见起源于HPS伴有心室内或束支缓慢传导。多形性室性心律失常常见于多个起源点 ,也见于单个起源点伴有冲动传导的逐搏变化。结论 :HPS电冲动参与器质性室性心律失常的触发和维持 ,以HPS电冲动为指导 ,可望改进器质性室性心律失常的消融技术和效果。

Relationship Between the Electrical Activity From the His-Purkinje System and the Spontaneous Ventricular Tachyarrhythmia Resulting From Myocardial Ischemia and Reperfusion in Dogs

The electrical activity from the His-Purkinje system (HPS) was recorded by plunge electrodes along the anatomic course of HPS in 25 dogs. The relationship between the electrical activity of HPS and the spontaneous ventricular tachyarrhythmia was observed in three-layers of cardiac muscles during occlusio n and release of the left descending coronary artery. Results showed that the bipolar electrogram at the earliest activation site of the spontaneous ventricular tachyarrhythmia was characterized by negative Q wave. When the arrhythmia originated from HPS, the HPS potentials preceded the ventricular potentials, whe n the arrhythmia originated from ordinary cardiac muscle, the ventricular potentials preceded the HPS potentials. Spontaneous HPS electrical activity without conduct ing to the surrounding area caused focal abnormality in the local electrogram, while conducting to the surrounding area, it triggered or driven the premature ventric ular beats, mono-morphic or multi-morphic ventricular tachycardia, ventricular flut ter and fibrillation. During the initial period of ventricular fibrillation, organized e lectrical activity was observed in the majority of the ventricle. During terminal period o f ventricular fibrillation, dissociation of the electrical activity from various p arts of ventricle was observed. During ventricular dissociation, the highest rate of ele ctrical activity was recorded along the HPS, indicating HPS electrical activity may play a critical role in driving ventricular fibrillation. Ventricular tachyarrhythmia w ith variable QRS morphology was observed either with variable earliest activation si tes or with relative constant earliest activation site but variable conduction time among the various portion of ventricle. Ventricular tachyarrhythmia with narrow QRS complexes usually indicates the origination from HPS, or from ordinary cardiac muscle with fast conduction through HPS. Ventricular tachyarrhythmia with widen QRS complexes may indicate the origination from ordinary muscles, but may also indicate the origination from HPS with conduction delay within the HPS or cardia c muscles. Our observation may provide the experimental basis for identifying and ablating ventricular tachyarrhythmia, especially ventricular fibrillation trigge red or driven by the electrical activity from His-Purkinje system.