缺血性室性心动过速折返机制的实验研究

The Experiment Study on Reentry Mechanism of the Ventricular Tachycardia Following Acute Myocardial Infarction

对１８条缺血性心肌模型犬中发生室性心动过速（简称室速）的６条犬采用组合双极电极记录心肌局部电图，进一步探讨缺血性心脏病室速的机制。结果显示：①缺血区各层心肌电图和心外膜局部电图上均出现延迟电位及碎裂波。②室速的激动顺序为缺血区心内膜（作参照，为０ｍｓ）、缺血区心外膜（１０±０．１０ｍｓ）、边缘区心内膜（１０±０．１２ｍｓ）、边缘区心外膜（１６±０．２０ｍｓ）、正常区心内膜（２０±０．５０ｍｓ）、正常区心外膜为（２７±０．２０ｍｓ）。③当体表ＩＩ导联心电图和心外膜、心肌局部电图均出现心室颤动时，心内膜仍表现为室速的图形。认为室速是多平面多折返所形成的“立体折返”激动的结果；

To explore the mechanism of ventricular tachycardia in ischemic heart disease,the intramyocardial electrograms were recorded by a specially designed composite bipolar electrodes in six of eighteen conscious,acute instrumented mongrel dogs after occlusion of the left anterior descending coronary artery during ventricular tachycardia.The results showed that: (1)the slow inhomogenous conduction and fractionated electrograms occured only in the areas of the ishemic myocardia and epicardium;(2)the premature excitement was almost simultaneous in the area of the ischemic epicardium and the edge area of the ischemic endocardium;(3)the ventricular tachycardia in the area of the ischemic endocardium was still recorded when the ventricular fibrillation occured in other area.Therefore,we consider the ventricular tachycardia should be due to anisotropic 'three dimensions reetrant circuits' mechanism and it suggest that it should be important how to search for entrance to the circuits in radiofrequency catheter ablation.