房室结折返性心动过速射频消蚀治疗的体会

RADIOFREOUENCY TRANSCATHETER ABLATION OF DUAL ATRIOVENTRICULAR NODAL REENTRANT TACHYCARDIA

２４例（２４％）房室结折返性室上速经射频消蚀慢径，随诊２个月以上。在希氏束近端记录到一低振幅波（小Ｂ波），ＡＢ间期３５～６５ｍｓ，较ＡＨ间期平均短２９ｍｓ。小Ｂ波随慢径而飞跃，射频并不使之消失。心动过速时该处ＶＡ间期最短。找到小Ｂ波处放电可用较低电能量、较短时间取得成功。１例产生慢性完全性房室传导阻滞者需安装永久性起搏器。１例复发再消蚀成功。

4 cases of dual atrioventricular nodal reentry tachycardia(DAVN RT)were identified by EPS.Radiofrequency transcatheter ablation(RFCA) was applied to interrupt the slow pathways(SP)con-duction with a large tip catheter in all the cases.The records from the ablation catheter in the first 8 cases were analysed retrospectively;a low amplitude, relatively slow spike(“B”wave)was found in all the successful cases.In the following 16 cases,“B”waves were purposely seeked for the site of ablation,which was usually on the middle and proximal third of the line between His bundle and coronary sinus Os AB Interval was measured,it ranged from 35 to 65ms with an average of 29ms,being shorter than the AH interval.“B”wave usually followed the“jump’from the fast to SP,and was not eliminated by RFCA,As compared with the original ablatlon method,less energy(22.8 vs 26.1W,P<0.01 ) and short-er time of X-ray exposure were needed,if the RF current was applied at“B”site. During the ablation,Awave should be much smaller than V wave,in order not to damage the AVN. The appearence of junctional rhythm usually indicates a successful ablation of SP,SP were eliminated in all the 24 cases.After a follow-up of more than 2 months, recurrence was found in one patient,who undement a sec-ond ablation. Complete AV block occurred in l patient, who had a pacemaker implanted.The presence of“B”wave possibly indicates the existence ofa short pathway between the fast and SP. RF current ap-plied at that site was safe and more effective.