Idiopathic left ventricular tachycardia originating from the mitral annulus

BACKGROUND: Radiofrequency catheter ablation (RFCA) can eliminate most idiopathic repetitive monomorphic ventricular tachycardias (RMVTs) originating from the right and left ventricular outflow tracts (RVOT, LVOT). Here, we describe the electrophysiological (EP) findings of a new variant of RMVT originating from the mitral annulus (MAVT). METHODS AND RESULTS: MAVT was identified in 35 patients out of 72 consecutive left ventricular RMVTs from May 2000 to June 2004. All patients underwent an EP study and RFCA. The sites of origin of the MAVT were grouped into four groups according to the successful ablation sites around the mitral annulus. Group I included the anterior sites (n = 11), group II the anterolateral sites (n = 9), group III the lateral sites (n = 6), and group IV the posterior sites (n = 9). The MAVTs were a wide QRS tachycardia with a delta wave-like beginning of the QRS complex. The transitional zone of the R wave occurred between V1-V2 in all cases. The 12-lead electrocardiogram (ECG) pattern might reflect the site of the origin of MAVTs around the mitral annulus. We proposed an algorithm for predicting the site of the focus and the tactics needed for successful RFCA of the MAVT. CONCLUSIONS: We described the EP findings of the new variant of RMVT, MAVT. Most MAVTs could be eliminated by RF applications to the endocardial mitral annulus using our proposed tactics.     

射频消融治疗特发性室性心动过速疗效观察

目的 :评价射频消融术治疗特发性室性心动过速 (室速 )临床疗效。方法 :5 6例特发性室速患者中 ,34例左室特发性室速采用EPT小、中弯大头导管 (或Webstr小弯大头 ) ,在左室行激动顺序标测和消融 ,以P电位较QRS起点提前 2 0ms以上作为消融靶点。 2 2例右室流出道室速采用Webster加硬导管在右室流出道行起搏标测 ,以起搏时与心动过速时体表 12导联QRS形态完全相同或最接近处为消融靶点 ,成功标准为放电过程中心动过速终止且不能诱发。结果 :5 1例患者消融成功 ,成功率 91.1%。 34例左室特发性室速中 30例靶点位于左室间隔中下部 ,2例近左室心尖 ,1例左室流出道 ,1例位于间隔高位。 31例消融成功 ,1例失败 ,2例因导管到达间隔处机械刺激终止室速而不能再诱发 ,于终止室速处作为靶点射频消融 ,1例于术后第 2天、另 1例半年后室速复发。 2 2例右室流出道室速 ,16例位于流出道间隔侧 ,6例位于流出道游离侧壁。 19例起搏标测到与心动过速 12导联QRS形态完全相同靶点 ,1例形态接近 ,消融获成功。 2例未能诱发室速 ,射频消融 1个月心动过速重新出现 ,所有患者无并发症出现。结论 :射频消融术对特发性室速是一种安全有效的治疗方法 ,可作为首选治疗。电生理未诱发室速或机械刺激终止室速不宜尝试射频消融治疗。     

特发性室性心动过速射频导管消融标测方法探讨

目的探讨特发性室性心动过速（IVT）的标测方法.方法对52例行射频消融的IVT患者进行标测.39例源于右心室的IVT采用消融导管右心室起搏标测法,以起搏时与室性心动过速（室速）发作时的12导联心电图QRS波形态与振幅完全相同的起搏部位为消融靶点.12例起源于左心室的IVT以发作时消融电极导管在左心室内标测到较体表心电图QRS波提前≥20 ms的最早高频低振幅电位为消融靶点（激动顺序标测法）,1例左心室室速采用起搏标测法.结果左心室IVT消融成功率100%（13/13）,右心室IVT消融成功率94.87%（37/39）.结论起源于左心室的IVT宜采用激动顺序标测法,起源于右心室的IVT宜采用起搏标测法.     

特发性室性心动过速及室性期前收缩的射频消融治疗

目的探讨射频导管消融(radiofrequency catheter ablation,RFCA)治疗特发性室性心动过速(idiopathic ventricular tachycardia,IVT)和室性期前收缩(premature ventricualr contraction,PVC)可行性、必要性和疗效。方法回顾性分析16例IVT、PVC患者采用激动顺序标测和起搏标测法确定室性心动过速(ventricular tachycardia,VT)、PVC的起源部位并行RFCA治疗的资料。结果 3例IVT中2例起源于左室间隔部左后分支的蒲肯野系统,1例起源于右心室流出道(right ventricular outflow tract,RVOT)游离壁,同时合并另一种游离壁起源的PVC,3例消融均成功,1例复发。13例PVC中7例起源RVOT间隔部,3例起源于RVOT游离壁,1例同时存在两种形态PVC(分别起源于ROVT间隔部和游离壁),2例起源于左心室流出道,13例消融成功,1例复发。结论 RFCA治疗IVT及特定部位的PVC是安全、有效且成功率高的一种方法。     

起源点邻近二尖瓣环的频发室性早搏体表心电图特征及射频消融治疗

目的评估起源点邻近二尖瓣环的频发室性早搏(简称室早)体表心电图特点及射频消融治疗效果。方法10例频发室早患者接受常规电生理检查及射频消融治疗,对所有病例12导联体表心电图进行分析。结果10例室早均消融成功,并证实起源点邻近二尖瓣环的不同部位,根据成功消融靶点将本组病例分为3组,二尖瓣环前侧壁组(4例)、二尖瓣环后侧壁组(3例)、二尖瓣环后间隔组(3例)。所有病例胸前导联R波移行区位于V1～V2导联,绝大部分病例V6导联可见s波。对各组二尖瓣环室早心电图做进一步比较,可概括出系列心电图判断指标用以估计消融靶点的部位。结论射频消融治疗起源点邻近二尖瓣环的频发室早可取得良好效果,掌握其体表心电图特点有助于判定室早的起源部位。     

Electrocardiographic characteristics of repetitive monomorphic right ventricular tachycardia originating near the His-bundle

INTRODUCTION: Most idiopathic nonreentrant ventricular tachycardia (VT) and ventricular premature contractions (VPCs) arise from the right or left ventricular outflow tract (OT). However, some right ventricular (RV) VT/VPCs originate near the His-bundle region. The aim of this study was to investigate ECG characteristics of VT/VPCs originating near the His-bundle in comparison with right ventricular outflow tract (RVOT)-VT/VPCs. METHODS AND RESULTS: Ninety RV-VT/VPC patients underwent catheter mapping and radiofrequency ablation. ECG variables were compared between VT/VPCs originating from the RVOT and near the His-bundle. Ten patients had foci near the His-bundle (HIS group), with the His-bundle local ventricular electrogram preceding the QRS onset by 15-35 msec (mean: 22 msec) and His-bundle pacing produced a nearly identical ECG to clinical VT/VPCs. The HIS group R wave amplitude in the inferior leads (lead III: 1.0 +/- 0.6 mV) was significantly lower than that of the RVOT group (1.7 +/- 0.4 mV, P < 0.05). An R wave in aVL was present in 6 of 10 HIS group patients, while almost all RVOT group patients had a QS pattern in aVL. Lead I in HIS group exhibited significantly taller R wave amplitudes than RVOT group. HIS group QRS duration in the inferior leads was shorter than that of the RVOT group. Eight of 10 HIS group patients exhibited a QS pattern in lead V1 compared to 14 of 81 RVOT group patients. HIS group had larger R wave amplitudes in leads V5 and V6 than RVOT group. CONCLUSION: VT/VPCs originating near the His-bundle have distinctive ECG characteristics. Knowledge of the characteristic QRS morphology may facilitate catheter mapping and successful ablation.     

射频导管消融治疗的特发性室性心律失常心电图特征分析

目的：探讨不同起源的特发性室性期前收缩（PVCs）和（或）室性心动过速（VT）的心电图特征,提出鉴别流程。方法根据射频导管消融PVCs/VT有效靶点或心室最早激动点的X线胸片进行定位,分析不同起源PVCs/VT的12导联心电图QRS波群。结果828例接受导管消融,580例起源于右心室,248例起源于左心室,左、右心室起源者胸导联移行指数＜0的分别占97.58%及7.24%;左和右心室流出道起源者下壁导联多数呈R型,V1上,多数右心室流出道起源者呈rS型,右室间隔起源呈QS型,主动脉瓣上起源者常呈rS或RS型;下壁导联上,左前分支起源者常呈qR型,左后分支起源者常呈rS型。结论结合体表心电图胸导联移行指数、下壁导联和V1上的QRS波群特征可初步判断特发性PVCs/VT的起源部位。     

Electrocardiographic characteristics of the variants of idiopathic left ventricular outflow tract ventricular tachyarrhythmias

Background: Despite similar QRS morphology, idiopathic repetitive monomorphic ventricular tachyarrhythmias (VTs) of left ventricular outflow tract (LVOT) are known to have the variants of different adjacent origins, including the aorto-mitral continuity (AMC), anterior site around the mitral annulus (MA), aortic sinus cusps (ASC), and epicardium. However, the electrocardiographic characteristics of those variants previously have not been evaluated fully.
Methods and Results: Based on the mapping site and successful ablation in 45 consecutive patients with LVOT-VTs, we classified them into VTs of AMC (n = 3), MA (n = 8), ASC (n = 32), and epicardial (n = 2) origins. In all patients, we performed activation mapping and an electrocardiographic analysis. All AMC-VTs patients had monophasic R waves in almost all the precordial leads, while those with anterior MA-VTs had an Rs pattern in some precordial leads except for lead V6, and those with ASC-VTs had a variable transitional zone in leads V1–4. There was no S wave in lead V6 in any group except for one patient with anterior MA-VTs. The intrinsicoid deflection time in the AMC-VTs patients and anterior MA-VTs patients was significantly greater than in those with ASC-VTs (P < 0.05). There was no significant difference in the R-wave amplitude in the inferior leads among the groups. Successful radiofrequency catheter ablation (RFCA) was achieved in all patients except for in those with epicardial origin VT.
Conclusions: Despite many morphological similarities, the LVOT-VTs originating from the AMC, anterior MA and ASC could be identified by our proposed electrocardiographic characteristics in order to safely perform RFCA.     

特发性室性心动过速的射频消融

目的对经射频消融术证实的特发性室性心动过速的病例进行总结分析,探讨室性心动过速的发病状况、心电图特点、消融靶点的确定及消融结果。方法对32例特发性室性心动过速的起源部位和体表心电图进行分析,所有患者在诱发出室性心动过速后进行射频消融治疗,观察特发性室性心动过速的射频消融成功率和复发率,以及它们和消融靶点的关系。结果右室特发性室性心动过速心电图表现为左束支传导阻滞,左室特发性室性心动过速心电图则多表现为右束支传导阻滞。消融靶点的确定右室特发性室性心动过速主要采用起搏标测法,左室特发性室性心动过速主要采用激动顺序标测法。右室流出道室速组在起搏标测起搏ECG和VT时ECG的12导联QRS波完全相同处消融成功率较高。结论室性心动过速发作时的体表心电图可初步估计特发性室性心动过速的起源部位,射频消融术治疗特发性室性心动过速成功率高、并发症少。     

体表心电图特征对特发性右心室流出道室性心动过速和室性早搏起源点的定位价值

目的 起源于右心室流出道(RVOT)不同位点的室性心动过速(VT)具有相应的心电图表现,本研究旨在摸索一种相对简单的根据体表心电图进行定位的方法 .方法 将RVOT分为游离壁和间隔而两大区,其中间隔面又分为9个区域.共320例RVOT-VT患者中,对213例既往消融成功患者的靶点与体表12导联心电图中QRS波形态之间的关系进行分析,并在消融前前瞻性地对另外107例患者的消融靶点进行预测,以检验其定位价值.结果 I导联对RVOT起源的VT有特殊的定位价值.在间隔面前部起源时,I导联以负向波为主,多为QS、Qr及rS型,随着起源点从前向后、从上向下,R波逐渐升高,其中起源于间隔侧中带(2、5、8区)时,以"M"型居多,在后壁时则表现为R波且有切迹.游离壁起源者的QRS时限明显延长,I和aVL导联的R波较间隔起源者高,而下壁导联的R波均较间隔的低(P<0.05).在前瞻性分析中,这些参数的敏感度、特异度、阳性和阴性预测值均较高.结论 RV-OT不同部位起源的VT有相应的心电图特征,其中I导联形态尤其具有定位价值,为RVOT心律失常起源提供了简便的定位标准.     

射频消融特发性室性心动过速对心室肌复极离散度的影响

目的 研究导管射频消融术（ＲＦＣＡ）对特发性室性惊动国过速速（ＩＶＴ）患者ＱＴ、ＪＴ离散度（ＡＴｄ、ＪＴｄ）的影响。方法 测量１５例ＩＶＴ患者ＲＦＣＡ术前、术后的ＱＴｄ、ＪＴｄ。结果 ＩＶＴ患者ＲＦＣＡ术关、术后ＱＴｄ、ＪＴｄ均无显著性差异（Ｐ〉０．０５）。结论 ＲＦＣＡ不影响ＩＶＴ患者心室肌复极离散度。     

起源于左右心室流出道心动过速和早搏的射频导管消融治疗

目的 探讨射频导管消融（RFCA）治疗心室流出道特发性室性心动过速（室速）和室性早搏（室早）的临床效果、心电图及电生理特征。方法 58例患者中室速10例,室早48例。起源于右室流出道（RVOT）43例,左室流出道（LVOT）15例,其中起源于主动脉瓣上Valsalva左冠窦（LSV）12例。5例RVOT室速是在非接触标测系统Ensite3000指导下进行消融的。结果 （1）58例患者中55例成功,3例失败,9例复发。（2）其中1例患者术中出现急性心包压塞。（3）起源心室流出道的室速和室早具有典型的心电图特征,其中Ⅱ、Ⅲ、aVF导联单向R波是流出道室性心律失常的共同特点。（4）V1或V2导联的R波时限指数与R／S波幅指数可作为区别LSV与RVOT室速和室早的有效指标。结论 射频导管消融治疗心室流出道特发性室性心律失常是一种安全、有效的方法。非接触标测系统对于血流动力学不稳定的复杂性室性心律失常的标测与治疗具有重要的意义。     

射频导管消融治疗特发性室性心动过速(附20例报告)

目的 特发性室性心动过速(IVT)的射频消融(RFCA)研究。方法共收集20例临床诊断IVT患者,男性14例。女性6例,年龄40.5±12.5(21～66)岁,病史7.8±8.8(1～22)年,心动过速时R—R间期为:309±69(240～430)ms。心动过速时心电图呈右束支传导阻滞(RBBB)型8例。左束支传导阻滞(LBBB)型,且Ⅱ、Ⅲ、avF主波向上12例。对20例患者进行心电生理检查及射频消融治疗。结果 20例均获成功,术后1例起源左心室后间隔,1例起源于右心室流出道之室性心动过速分别于术后第3、7天复发,余无室性心动过速复发,亦无并发症。结论RF—CA治疗IVT成功率高,RFCA关键在于靶点标测和标测方法的选择。     

起源于主动脉窦频发室性期前收缩的心电生理特征及射频消融治疗

目的报道11例起源于主动脉窦的频发室性期前收缩（premature ventricular contraction,PVC）患者的心电生理特征、射频消融（radiofrequency catheter ablation,RFCA）方法及疗效。方法分析患者术前体表心电图和动态心电图PVC的特点,测量V1或V2导联r波时限和振幅,计算r波与QRS波时限的比值及r波于S波振幅的比值。术中行主动脉窦内激动标测和起搏标测确定PVC起源部位,并行冠状动脉造影辅助定位后行RFCA。结果11例均有频发PVC,5例有反复短阵室性心动过速。下壁导联QRS波呈R形且高大直立,V1导联呈rS型,胸前导联多移行于V3以前,V6导联多呈Rs型或无S波。V1导联r波时限（84.6±9.8）ms,占QRS波时限的50%以上;r/S振幅比值0.72±0.31。有效消融靶点局部电图V波较体表心电图的QRS波明显提前（35.6±8.9）ms,有效靶点放电2～8 s见PVC减少至消失。结论起源于主动脉窦的PVC其下壁导联QRS波呈R形且高大直立,V1或V2导联r波时限宽（〉50%同导联QRS波）,r波振幅高（〉30%同导联S波）;主动脉窦内PVC的射频消融治疗是安全、有效的。     

儿童和青少年快速性心律失常的临床特点

研究儿童和青少年快速性心律失常的临床特点。选择 1995～ 2 0 0 2年在我院行射频消融 (RFCA)治疗的儿童和青少年快速性心律失常患者 ,共 32 1例 ,男 2 10例、女 111例 ,年龄中位数 13.4± 3.6 (1.5～ 18)岁 ;其中 ,房室折返性心动过速 (AVRT) 2 0 4例、房室结折返性心动过速 (AVNRT) 74例、特发性室性心动过速 (IVT) 35例、房性心动过速 (AT) 5例、心房扑动 (AFL) 2例、不适当窦性心动过速 (IST) 1例。记录所有病例术前未发作心动过速及心动过速发作时的体表 12导联心电图 ,结合电生理检查 ,分析其临床特点。结果 :AVRT、AVNRT和IVT分别占6 3.6 %、2 3.1%和 10 .9%。年岁较小的儿童和青少年 ,右侧旁道较多 ,随着年龄的增加 ,左侧旁道相对越来越多。B型预激合并多旁道较常见。 35例IVT ,其中 2 3例为左室IVT ;6例为右室IVT。 12例合并先天性心脏病 ;13例并发心动过速性心肌病 ,心功能及心脏大小在RFCA术后 3～ 6个月恢复正常。结论 :①AVRT、AVNRT和IVT是儿童和青少年快速性心律失常中最常见的 3种类型。②心动过速性心肌病经早期适当的治疗是可逆的。     

Twelve‐lead electrocardiographic localization of idiopathic premature ventricular contraction origins

The major sites of origins of idiopathic ventricular arrhythmias have been elucidated. Idiopathic ventricular arrhythmias most often present as premature ventricular contractions (PVCs) with a focal mechanism, and commonly occur without structural heart disease. Idiopathic ventricular arrhythmias usually originate from specific anatomical structures, commonly endocardial but sometimes epicardial and exhibit characteristic electrocardiograms (ECGs) based on their anatomical background. There are general and specific ECG characteristics that can localize the site of idiopathic PVC origins. The general ECG characteristics include the bundle branch block pattern, axis, QRS polarity in lead V6, QRS duration, precordial transition, maximal deflection index, and so forth. They can roughly localize the site of idiopathic PVC origins. Several major sites of idiopathic PVC origins are located close to each other, and specific ECG characteristics are helpful for localizing the site of origins more accurately in those PVCs. Twelve‐lead surface ECG algorithms usually can localize the site of idiopathic PVC origins with a high accuracy, but their accuracy can be limited by the patients’ physique, heart rotation, specific conduction properties, presence of structural heart disease, and so forth. This review describes an overview of the approaches to the 12‐lead surface ECG localization of idiopathic PVCs, and also discusses their caveats and limitations.     

瓣环部起源的特发性室性期前收缩射频导管消融治疗研究

目的探讨瓣环部起源的特发性室性期前收缩患者的体表心电图特点及射频导管消融（下称消融）治疗的疗效与安全性。方法对8例瓣环起源的特发性室性期前收缩患者行消融治疗,并分析其心电图的QRS波群特征。结果所有患者均消融成功。无并发症发生。根据X线影像定位,起源于三尖瓣环侧（游离）壁6例、三尖瓣环前间隔1例、二尖瓣环前侧壁1例。结论消融治疗瓣环部起源的特发性室性期前收缩安全有效,掌握体表心电图特点有助于消融前初步判定其起源部位。     

Idiopathic ventricular arrhythmias originating from the tricuspid annulus: Prevalence, electrocardiographic characteristics, and results of radiofrequency catheter ablation

BACKGROUND: Idiopathic ventricular tachycardias (VTs) and premature ventricular contractions (PVCs) arising from the tricuspid annulus have been reported. OBJECTIVE: The purpose of this study was to clarify the prevalence and characteristics of VT/PVCs originating from the tricuspid annulus. METHODS: The ECG characteristics and results of radiofrequency (RF) catheter ablation were analyzed in 454 patients with idiopathic VT/PVCs. RESULTS: Thirty-eight (8%) patients had VT/PVCs arising from the tricuspid annulus: 28 VT/PVCs (74%) originated from the septal portion of the tricuspid annulus and the remaining 10 (26%) from the free wall of the tricuspid annulus. QRS duration and Q-wave amplitude in each of leads V1-V3 were greater in VT/PVCs arising from the free wall of the tricuspid annulus than those from the septum of the tricuspid annulus (all P < .01). "Notching" of the QRS complex was observed more often in VT/PVCs arising from the free wall of the tricuspid annulus than those from the septum of the tricuspid annulus (P < .01). A Q wave in lead V1 was observed more often in VT/PVCs arising from the septum of the tricuspid annulus than those from the free wall of the tricuspid annulus (P < .005). R-wave transition occurred beyond lead V3 more often in VT/PVCs arising from the free wall of the tricuspid annulus than those from the septum of the tricuspid annulus (P < .005). RF catheter ablation eliminated 90% of the VT/PVCs arising from the free wall of the tricuspid annulus but only 57% of the VT/PVCs arising from septum of the tricuspid annulus. CONCLUSION: Idiopathic VT/PVCs arising from tricuspid annulus are not rare, and the detailed origin can be determined by ECG analysis. The preferential site of origin was the septum but also could be the free wall of the tricuspid annulus.     

Electrocardiographic and morphometric features in patients with ventricular tachycardia of right ventricular origin

Objective—To study differences between repetitive monomorphic ventricular tachycardia (RMVT) of right ventricular origin, and ventricular tachycardia in arrhythmogenic right ventricular dysplasia (ARVD).
Patients—Consecutive groups with RMVT (n = 15) or ARVD (n = 12), comparable for age and function.
Methods—Analysis of baseline, tachycardia, and signal averaged ECGs, clinical data, and right endomyocardial biopsies. Pathological findings were related to regional depolarisation (QRS width) and repolarisation (QT interval, QT dispersion).
Results—There was no difference in age, ejection fraction, QRS width in leads I, V1, and V6, and QT indices. During ventricular tachycardia, more patients with ARVD had a QS wave in V1 (p < 0.05). There were significant differences for unfiltered QRS, filtered QRS, low amplitude signal duration, and the root mean square voltage content. In the absence of bundle branch block, differences became non-significant for unfiltered and filtered QRS duration. Mean (SD) percentage of biopsy surface differed between RMVT and ARVD: normal myocytes (74(3.4)% v 64.5(9.3)%; p < 0.05); fibrosis (3(1.7)% v 8.9(5.2)%; p < 0.05). When all patients were included, there were significant correlations between fibrosis and age (r = 0.6761), and fibrosis and QRS width (r = 0.5524 for lead I; r = 0.5254 for lead V1; and r = 0.6017 for lead V6).
Conclusions—The ECG during tachycardia and signal averaging are helpful in discriminating between ARVD and RMVT patients. There are differences in the proportions of normal myocytes and fibrosis. The QRS duration is correlated with the amount of fibrous tissue in patients with ventricular tachycardia of right ventricular origin.

Keywords: arrhythmogenic right ventricular dysplasia; electrocardiography; endomyocardial biopsy; ventricular arrhythmias     

Electrocardiographic predictors of failure and recurrence in patients with idiopathic right ventricular outflow tract tachycardia and ectopy who underwent radiofrequency catheter ablation

This study reports new electrocardiographic (ECG) predictors of radiofrequency catheter ablation failure and recurrence in idiopathic right ventricular outflow tract (RVOT) ventricular tachycardia (VT) or ectopy based on 91 consecutive patients. Procedural success and failure rates were 85% (77/91) and 15% (14/91), respectively. Twenty three percent (18/77) had recurrence during the follow-up period of 1 to 120 months (mean 56 +/- 31 months). Baseline RVOT VT/ectopy on 12-lead ECG taken prior to ablation from 91 patients were retrospectively analyzed. Ablation performed with RVOT ectopy (isolated ectopies, bigeminy, trigeminy, or couplets) as template arrhythmia was more likely to fail (30% vs. 8%, P =.02) as opposed to RVOT VT (sustained or nonsustained). VT/ectopy-QRS morphology variation was more observed in failed ablations (36% vs. 7%, P =.001). Significantly wider mean VT/ectopy QRS in leads I, II, AVR, V2, V3, V5, and V6 were noted in failed ablation group. Mean R wave amplitude reached statistical significance only in lead II (22.0 +/- 5.1 mV for failed vs. 17.8 +/- 5.2 mV for successful outcomes; P =.009). QRS morphologic variation (47% vs. 16%; P =.009) was the only statistically significant ECG to be more common in patients with arrhythmia recurrence. In conclusion, ablation with ectopy over VT as template arrhythmia, presence of QRS morphologic variation, wider mean QRS width, and taller mean R-wave amplitude in lead II were identified ECG predictors of failed RVOT VT/Ectopy ablation. The only ECG predictor of recurrence was the presence of RVOT VT or ectopy QRS morphologic variation.