摘要：心肌梗死(MI)后室性心动过速(VT)的基质存在解剖上的复杂性并且血液动力学常常是不稳定的，因此射频导管消融的成功率是有限的。本研究的目的是运用电解剖标测(CARTO)指导VT的射频消融，以便弄清折返环和梗死区的关键峡部，此可能增加临床消融的效率。19例MI的病人(年龄66±7岁，其中男性17例)因VT拟作20次消融［17例在服用抗心律失常药，7例已安装埋藏式心脏转复除颤器(ICD)］。所有病例均反复发作临床型VT(周期为423±87 ms)。在VT时或窦律/右室起搏(SR/RVP)行左室CARTO标测。对13例14次血液动力学稳定的VT实施标测，包括2例无休止性慢VT。仅8例临床性VT，在心动过速时完成了整个左室的重建，另6例因反复机械损伤MI区内关键性峡部，使临床型VT不再诱发。12例在SR/RVP时完成左室标测，包括6例关键性峡部损伤及6例血液动力学不稳定者。在8例CARTO标测的VT中，有3例呈现典型的“8字”型折返环，2例沿二尖瓣(MA)激动心室。在8例VT中，于关键性峡部放电消融，其中6例VT终止，平均放电2次；然后行线性消融连接两个疤痕区域或连接疤痕与MA环，平均放电16次。在SR/RVP时标测，可见1个或多个疤痕区域，4例在诱发VT时放电，均终止了VT；另8例因极不稳定的血液动力学或机械损伤，在SR/RVP时行放电消融。消融后仍有2例可诱发临床型VT。平均随访11个月，1例临床型VT复发，另5例病人也安装ICD。结论：①对VT病例，尤其是血液动力学不稳定的VT，通过CARTO标测可清楚地呈现整个或部分折返环以及梗死心肌区内的关键性峡部，于两疤痕或一个疤痕与MA之间行线型消融可消除临床型VT并预防复发。②在临床型VT标测时，常常发生关键性峡部的机械损伤，这高度提示关键性峡部位于心内膜下浅层，此利于导管消融。

分类号：R319R541.7⁺1文献标识码：A

文章编号：1007—2658(2000)01—0012—04

Catheter Ablation of Ischemic Monomorphologic Ventricular Tachycardia by Using the Electroanaomical (CARTO) Mapping System.

OUYANG Fei-fanKarl-Heinz Kuck.

Abstract：The substrate of ischemic ventricular tachycardia (VT) is anatomically complex and hemodynamics is often unstable,the success rate of radiofrequency catheter ablation is very limited.The aim of the study was to investigate that use of the electroan-atomical mapping system (CARTO) for catheter ablation of VT can understand reentry circuit and a critical isthmus within the infarcted myocardium,may improve clinical efficacy.Between 6/1997 and 7/1999,19 post-MI patients (66±7 yrs,17 male) were referred for RF ablation of VT (17 pts under antiarrhythmic drugs and 7 pts with ICD therapy) with 20 procedures.The clinical VTs (CL=423±87 ms,280-620 ms)were easioly reproducible induced in all pts.CARTO mapping of the left ventrculae (LV) was attempted to perform during VT or during sinus rhythm/right ventricular pacing (SR/RVP).Mapping VT was performed in 14 hemodynamically stable VTs in 13 pts,including 2 pts with incessant slow VT.The entire reconstruction of the LV was only complete during 8 clinical VTs due to mechanic injury of critical isthmus within the infarcted myocardium resulting in noninducibility of clinical VT in 6 pts.Mapping LV during SR/RVP was completed in 12 pts including 6 pts with mechanic injury of critical isthmus and 6 pts with hemodynamically unstable VT.In 8 mapped VTs,the activation mapping was shown typical “figure of 8” in 3 pts and along the mitral anulus (MA) in 2 pts.RF current was delivered to a critical isthmus constrained by 2 large scars or inferior scar and MA during 8 mapped VTs,terminated VT with mean 2 RF applications in 6 VTs and connected them with additional 16 RF application.In reconstructed LV during SR/RVP,multiple scars with one or more isthmuses were presented on the reconstruction of the LV.RF current was delivered during hemodynamically unstable VT in 4 pts and abolished all VTs,in other 8 pts RF current was delivered only SR/RVP pacing due to very unstable hemodynamic status or mechanic in jury.In the 12 pts the clinical VT was only reinitiated in 2 pts after procedure.During mean follow-up of 11 months,clinical VT recurred in one pt,5 other pts peceived ICD therapy.Conclusion:1) In patients with VT,even unstable hemodynamic VT,use of CARTO mapping can visualize entire or part reentry circuit and a critical isthmus within infarcted myocardium and can abolish clinical VT and prevent recurrence by linear lesion connecting two scars or a scar and MA.2) machanic injury of critical isthmus often occurs during mapping clinical VT,this highly suggests that the critical isthmus was located in superficial subendocardium and convenient for catheter ablation.［Chinese Journal of Cardiac Pacing and Electrophysiology,2000,14(1):12～15］

Key Wods：Electroanatomical mapping systemMyocardia infarctionVentricular tachycardiaCatheter ablation,radiofrequence current▲

心肌梗死(简称心梗)后2%～5%患者有持续性单形性室性心动过速(简称室速)发作，其由折返机制所致。这些病人室速常反复发作，且40%以上病例抗心律失常药物不能预防复发^［1］。植入埋藏式心脏转复除颤起搏器(ICD)可通过抗心动过速起搏或给予电休克(shock)终止心动过速，挽救生命，但不能预防复发。在高度选择性患者中，外科手术可根治此种心律失常，但手术相关的死亡率可达9%～20%^［2～3］。由于心梗后室速折返环大，难以定位整个折返环，常规X线指导下射频消融成功率低，且复发率高。最近我们在三维电解剖标测系统即CARTO标测系统的指导下，研究心梗后室速射频消融的可行性及临床疗效。

1资料与方法

1.1临床资料1997年6月至1999年7月19例反复发作室速的病例，其中男17例、女2例，年龄66±7(55～80)岁。10例有前壁心梗，其中8例有前壁室壁瘤；9例有下壁心梗，其中6例有下壁室壁瘤。左室造影测量射血分数为0.30±0.08(0.21～0.46)。17例手术期间使用抗心律失常药物，其中15例长期服用胺碘酮。7例术前已植入ICD。术前临床型室速周长为423±87(280～620) ms。

1.2电生理检查及CARTO标测常规穿刺左、右股静脉置2根6F Josephson 4极电极于右室心尖及右室流出道。术中常规置7F Swan-Ganz导管于左或右肺动脉监测肺动脉压力及肺毛细血管楔嵌压，另穿刺右股动脉监测其压力。CARTO标测前行程序刺激右室，采用两个不同周长附加1～3个期前刺激诱发临床型室速，并观察其血液动力学变化。2例术前及术中为无休止性室速，另17例中有1例经历过两次射频消融术。其中12例可反复诱发血液动力学稳定的临床型室速，另6例可诱发血液动力学不稳定的临床型室速。CARTO标测中，空间定位电极置入病人背部，时间定位电极取室速发作时或窦律时胸前导联QRS波群中最高振幅点或最低振幅点，标测左室采用Biosense Navi-Star标测电极经右股动脉或/和穿刺房间隔进入左室。标测采用双极和单极同时记录，滤波范围分别为10～400 Hz和0～400 Hz。

若患者为无休止性室速或血液动力学稳定性的室速，CARTO标测在心动过速中进行。所有患者血液动力学不稳定，CARTO标测在窦性心律或右室起搏下进行。所有病例在完成标测右必须分析局部电位，以局部电位振幅＜0.3 mV为疤痕组织。对于血液动力学稳定性室速，使用CARTO传导标测及拖带标测分析折返环部位、关键性峡部(Critical isthmus)及其与疤痕组织的关系，最后于峡部处射频消融。对于血液动力学不稳定性室速，分析窦律标测时疤痕分布，精标疤痕组织区域是否有高电压电位存在，将导管置入两个疤痕组织间，然后诱发室速，观察局部电图变化，并行拖带标测，以确定此部分是否为心动过速的关键部位和慢传导区域，若未能诱发室速，在两疤痕组织间行起搏标测，观察起搏时12导联心电图与发作时12导联心电图的关系，以便确定此区域是否位于折返环内，且是否为折返环的关键部位，最终行线性射频消融连接两个疤痕组织或疤痕至二尖瓣环。所有射频放电均在温控下进行。

2结果

2例无休止性室速患者CARTO标测仅在心动过速时进行。12例反复诱发血液动力学稳定性的室速中有6例CARTO标测在心动过速时进行；另6例因反复机械性损伤终止临床型室速，且使临床型心动过速不再诱发，CARTO标测需另在窦律或右室起搏时进行。8例CARTO标测室速中，有3例呈现出典型的“8字”型折返环并可清楚地证明其位于两个疤痕区域中的关键性峡部为心动过速缓传导区域，拖带标测符合隐性拖带(图1)，射频放电于此即刻终止心动过速(图2)。另2例室速沿二尖瓣激动心室。8例中6例射频消融放电终止心动过速，平均放电次数为2(1+4)次，然后行线性消融连接两个疤痕区域或连接疤痕与二尖瓣环，平均放电16(5～31)次。2例射频放电未能终止心动过速，成功