起搏法定位不同类室速起源点正确性的实验研究

Experimental study on the accuracy of locating the origins of various ventricular tachycardia by pacing

目的 :探讨起搏法定位不同类室性心动过速 ( VT)起源点的的正确性。方法 :犬 10条 ,记录心室 7位点心外膜、肌层及内膜下层起搏心电图 ( ECG) ,结扎冠状动脉前降支中段及吻合侧支 ,并记录原位点各层起搏 ECG,与结扎前对照。结果 :1两者起搏 ECG差异显著 ;2结扎前各位点及各层次起搏 ECG变化明显 ;3梗死区及其周边位点可出现相似的起搏 ECG且各层次起搏 ECG变化不明显。结论 :1起搏法标测特发性 VT起源点正确性较高 ;2起搏法标测心梗后 VT起源点的正确性不高 ;3体表 ECG定位心梗后 VT起源点的可靠性亦较差 ;4特发性 VT体表心电图判断 VT起源点的规律不适用于心梗后 VT。

AIM:To investigate the accuracy of locating the origins of various ventricular tachycardia(VT) by pacing. METHODS:the pacemaker ECGs were recorded on 21 sites of which were 7 in the epicardium, 7 in the myocardium and 7 in the endocardium, in each of the 10 dogs tested, and the results were compared with those of the same sites obtained after the anterior interventricular branch of left coronary artery and anastomotic branch were ligated. RESULTS: It was found that the differences between these two groups of the pacemaker ECGs were marked. The pacemaker ECGs on all the sites of different layers were markedly different from one another before the ligation . However, the pacemaker ECGs on the sites in and around the infarcted zone were similar, and so were those on the different layers of one site. CONCLUSION: The localization of the origin of idiopathic VT by pacing was fairly accurate. On the contrary, the localization of the origin of VT after myocardial infarction by pacing was not accurate enough, and neither was that by the surface ECG. The regulation for locating the origins in idiopathic VT by surface ECG is not applicable to VT after myocardial infarction.