Preferential conduction across the ventricular outflow septum in ventricular arrhythmias originating from the aortic sinus cusp.

OBJECTIVES: The purpose of this study was to examine the relationship between the origin and breakout site of idiopathic ventricular tachycardia (VT) or premature ventricular contractions (PVCs) originating from the myocardium around the ventricular outflow tract. BACKGROUND: The myocardial network around the ventricular outflow tract is not well known. METHODS: We studied 70 patients with idiopathic VT (n = 23) or PVCs (n = 47) with a left bundle branch block and inferior QRS axis morphology. Electroanatomical mapping was performed in both the right ventricular outflow tract (RVOT) and aortic sinus cusp (ASC) during VT or PVCs. RESULTS: The earliest ventricular activation (EVA) was recorded in the RVOT in 55 patients (group R) and in the ASC in 15 (group A). In all group R patients, the closest pace map and successful ablation were achieved at the EVA site. Although a successful ablation was achieved at the EVA site in all group A patients, the closest pace map was obtained at the EVA site in 8 and RVOT in 7 (with an excellent pace map in 4). The stimulus to QRS interval was 0 ms during pacing from the RVOT and 36 +/- 8 ms from the ASC. The distance between the EVA and perfect pace map sites in those 4 patients was 11.9 +/- 3.0 mm. CONCLUSIONS: Ventricular arrhythmias originating from the ASC often show preferential conduction to the RVOT, which may render pace mapping or some algorithms using the electrocardiographic characteristics less reliable. In some of those cases, an insulated myocardial fiber across the ventricular outflow septum may exist.     

Variation of QRS morphology of premature ventricular contractions originate from the left‐ventricular outflow tract during ablation

Idiopathic ventricular arrhythmias originating from the aortic sinus of Valsalva often show preferential conduction to the right‐ventricular outflow tract, which may render radiofrequency ablation more difficult. We describe a patient with symptomatic premature ventricular contractions of left‐ventricular outflow tract origin presenting with a variation of QRS morphology during ablation. The correlation between the characteristics of local voltage potentials and the real origin site of the ventricular arrhythmia is discussed.     

Repetitive monomorphic ventricular tachycardia originating from the aortic sinus cusp: electrocardiographic characterization for guiding catheter ablation

OBJECTIVES: We sought to investigate the electrocardiographic (ECG) characteristics for guiding catheter ablation in patients with repetitive monomorphic ventricular tachycardia (RMVT) originating from the aortic sinus cusp (ASC). BACKGROUND: Repetitive monomorphic ventricular tachycardia can originate from the right ventricular outflow tract (RVOT) and ASC in patients with a left bundle branch block (LBBB) morphology and an inferior axis. METHODS: Activation mapping and ECG analysis was performed in 15 patients with RMVT or ventricular premature contractions. The left main coronary artery (LMCA) was cannulated as a marker and for protection during radiofrequency delivery if RMVT originated from the left coronary ASC. RESULTS: During arrhythmia, the earliest ventricular activation was recorded from the superior septal RVOT in eight patients (group 1) and from the ASC in the remaining seven patients (group 2). The indexes of R-wave duration and R/S-wave amplitude were significantly lower in group 1 than in group 2 (31.8+/-13.5% vs. 58.3+/-12.1% and 14.9+/-9.9% vs. 56.7+/-29.5%, respectively; p < 0.01), despite similar QRS morphology. In five patients from group 2, RMVT originated from the left ASC, with a mean distance of 12.2+/-3.2 mm (range 7.3 to 16.1) below the ostium of the LMCA. In the remaining two patients, the RMVT origin was in the right ASC. All arrhythmias were successfully abolished. None of the patients had recurrence or complications during 9+/-3 months of follow-up. CONCLUSIONS: On the surface ECG, RMVT from the ASC has a QRS morphology similar to that of RVOT arrhythmias. The indexes of R-wave duration and R/S-wave amplitude can be used to differentiate between the two origins. Radiofrequency ablation can be safely performed within the left ASC with a catheter cannulating the LMCA.     

Left Ventricular Outflow Tract Tachycardia Including Ventricular Tachycardia from the Aortic Cusps and Epicardial Ventricular Tachycardia

Idiopathic outflow tract ventricular tachycardia (VT) can arise from the right (RVOT) or left ventricular outflow tract (LVOT). The electrocardiographic (ECG) pattern of RVOT VT is typical in most patients, showing a monomorphic left bundle branch block (LBBB) QRS morphology with an inferior axis. Radiofrequency catheter ablation can be performed with a high success rate and provides a curative therapeutic approach. However, not all VTs with LBBB and inferior axis can be ablated from the RVOT. It has become apparent that LVOT VTs including VT originating from the aortic sinus of Valsalva or epicardium represent underrecognized VT entities which are also amenable to successful catheter ablation. Twelve-lead ECG criteria can contribute to distinguish between sites of VT origin.LVOT arrhythmias represent an increasingly recognized VT entity which can be safely and successfully treated by catheter ablation. Identification of VT origin using ECG criteria and differentiation of LVOT versus RVOT origin is essential in the careful planning of the ablation strategy.     

右室流出道起源与主动脉窦起源室性早搏的分析

目的 探讨右室流出道起源与主动脉窦起源室性早搏心电图的主要区别.方法 回顾分析因频发室性早搏,心电图室性早搏胸前导联呈左束支传导阻滞,Ⅱ、Ⅲ、aVF导联QRS主波向上,行射频消融成功的患者126例,分为右室流出道（RVOT）起源组66例,主动脉窦（ASC）起源组60例.结果 V1、V2导联R波时限指数和R/S波幅指数ASC组高于RVOT组.胸前导联移行区指数RVOT组高于ASC组.ROC曲线分析胸前导联移行区指数鉴别室性早搏起源有较高价值.结论 心电图呈左束支传导阻滞且Ⅱ、Ⅲ、aVF导联QRS主波向上的室性早搏,分析V1、V2导联R波时限指数、R/S波幅指数和胸前导联移行区指数可判断RVOT起源与ASC起源,指导射频消融治疗.     

Electrocardiographic pattern as a guide for management and radiofrequency ablation of idiopathic ventricular tachycardia

BACKGROUND: Idiopathic ventricular tachycardia (VT) often originates from the right ventricular outflow tract (RVOT), but foci deep to the endocardium, in the epicardium, or in the left ventricle are not uncommon. Although these extra-RVOT foci can be targeted with ablation, risks involved are higher and success rates lower. Simple electrocardiographic (ECG) criteria allowing (1) discrimination of RVOT foci from extra-RVOT foci and (2) assessment of the chance of success of a right heart ablation procedure are desirable. METHODS: Twenty-five consecutive patients referred for radiofrequency (RF) ablation of idiopathic VT or severely symptomatic idiopathic ventricular premature contractions were included. Localization of VT origin and success rates of VT ablation in the RVOT were analyzed according to the ECG pattern. RESULTS: The analysis of the R wave in V2 was the strongest single predictor of whether the VT had an RVOT or an extra-RVOT origin. An R wave amplitude < or =30% of the QRS amplitude designated the VT focus in the RVOT with positive and negative predictive values of 95 and 100%, respectively. Analysis of R wave duration in V2 had similar predictive values, whereas the R/S transition zone in precordial leads had slightly lower predictive values. Seventeen of 20 arrhythmias (85%) with an R wave amplitude < or =30% of the QRS amplitude in V2 could be successfully abolished by an exclusively right heart procedure. CONCLUSIONS: The analysis of ECG pattern makes it possible to guide the management of patients with idiopathic VT in predicting the arrhythmias that can be safely targeted with RF ablation from the RVOT with high success rates.     

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68 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:本组特发性室性心动过速患者中右室室性心动过速较左室室性心动过速多见。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时起搏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。     

Ventricular tachycardia with an outflow tract septal origin after repair of double outlet right ventricle.

A 12-year-old boy born with double outlet right ventricle (RV) developed sustained ventricular tachycardia (VT) 6 years after the corrective surgery and underwent electrophysiologic testing and catheter ablation. Electroanatomic mapping of the right and left ventricles during the VT revealed a centrifugal activation from the outflow tract septum. Though an excellent pace map was obtained in the RV, successful ablation was achieved on the left side. These findings suggested that the VT origin might have been located in the intramural region of the ventricular outflow tract septum with a preferential breakout site in the RV outflow tract.     

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。     

Idiopathic premature ventricular contractions arising from the pulmonary artery: importance of mapping in the pulmonary artery in left bundle branch block-shaped ventricular arrhythmias.

A patient underwent radiofrequency (RF) catheter ablation of symptomatic idiopathic ventricular contractions (PVCs). RF energy applications at 2 sites in the right ventricular outflow tract (RVOT), where both the earliest ventricular activation and near-perfect pace mapping were obtained, did not abolish the PVC but resulted in changes in the QRS morphology of the PVC. Complete elimination of the PVC was achieved with RF energy application at a site within the pulmonary artery 13 mm above the pulmonary valve, which was greater than 20 mm away from the failed ablation sites within the RVOT.     

Electrocardiographic patterns of superior right ventricular outflow tract tachycardias: distinguishing septal and free-wall sites of origin

INTRODUCTION: The superior right ventricular outflow tract (RVOT) septum and free wall are common locations of origin for outflow tract ventricular tachycardias (VT). We hypothesized that (1) unique ECG morphologies of pace maps from septal and free-wall sites in the superior RVOT could be identified using magnetic electroanatomic mapping for accurate anatomical localization; and (2) this ECG information could help facilitate pace mapping and accurate VT localization. METHODS AND RESULTS: In 14 patients with structurally normal hearts who were undergoing ablation for outflow tract VT, a detailed magnetic electroanatomic map of RVOT was constructed in sinus rhythm, then pace mapping was performed from anterior, mid, and posterior sites along the septum and free wall of the superior RVOT. Pace maps were analyzed for ECG morphologies in limb leads and transition patterns in precordial leads. Monophasic R waves in inferior leads for septal sites were taller (1.7 +/- 0.4 mV vs 1.1 +/- 0.3 mV; P < 0.01) and narrower (158 +/- 21 msec vs 168 +/- 15 msec; P < 0.01) compared with free-wall sites; lacked "notching" (28.6% vs 95.2%; P < 0.05); and showed early precordial transition (by lead V4; 78.6% vs 4.8%; P < 0.05). A positive R wave in lead I also distinguished posterior from anterior septal and free-wall sites. Based on QRS morphology in limb leads and precordial transition pattern (early vs late), in a retrospective analysis, a blinded reviewer was able to accurately localize the site of origin of clinical arrhythmia (the successful ablation site on the magnetic electroanatomic map) in 25 of 28 patients (90%) with superior RVOT VT. CONCLUSION: Pace maps in the superior RVOT region manifest site-dependent ECG morphologies that can help in differentiating free-wall from septal locations and posterior from anterior locations. Despite overlap in QRS amplitude and duration, in the majority of patients a combination of ECG features can serve as a useful template in predicting accurately the site of origin of clinical arrhythmias arising from this region.     

单导管射频消融治疗右室流出道室性期前收缩

目的:观察单导管射频消融治疗右室流出道室性期前收缩（室性早搏,室早）的安全性和临床效果。方法: 经常规体检、生化检查、X线胸片、心脏彩超、长程心电图等各种检查后,入选65例患者,采用温控消融导管以起搏为主的方法进行标测,并对单导管射频消融的安全性和临床效果进行总结。结果: 消融即刻成功率97%(63/65),其中2例放弃消融术;随访15～40个月,有3例复发并再次手术,成功2例,总成功率为95%（62/65）,无复发。电生理检测和消融时间:(50±27) min;曝光时间:(8.1±3.8) min,所有患者术中及术后均未发生消融相关并发症。结论: 单导管射频消融治疗右室流出道室早安全有效,并能减少消融操作及X线暴露时间。     

Idiopathic ventricular arrhythmias arising from the pulmonary artery: Prevalence, characteristics, and topography of the arrhythmia origin

BACKGROUND: The characteristics of idiopathic ventricular tachycardias (VTs) or idiopathic premature ventricular contractions (PVCs) arising from the pulmonary artery (PA) have not been sufficiently clarified. OBJECTIVE: The purpose of this study was to clarify the prevalence, characteristics, and preferential sites of idiopathic VT/PVCs arising from the PA (PA-VT/PVCs). METHODS: Data obtained from 276 patients with idiopathic VT/PVCs who underwent radiofrequency (RF) catheter ablation were analyzed. RESULTS: Twelve VT/PVCs (4%) were PA-VT/PVCs, and their onset (34 +/- 14 years) was the youngest among all subgroups. Because those QRS morphologies were similar to VT/PVCs arising from the right ventricular outflow tract (RVOT-VT/PVC) and the earliest ventricular activation was from the RVOT, an initial ablation was performed in the RVOT in all patients. However, RF catheter ablation at the RVOT resulted in a QRS morphology change in all patients, so thereafter PA mapping and ablation was performed. A characteristic potential during sinus rhythm and/or the arrhythmia was recorded at the successful PA ablation site in all patients. A perfect or good pace map was obtained in 7 (70%) of 10 patients. The successful ablation site was the septal side of the PA close to the posterolateral attachment in 9 patients (75%) and the septal side close to the anterior attachment in the remaining 3 (25%). No PA-VT/PVCs recurred during follow-up of 27 +/- 13 months. CONCLUSION: PA-VT/PVCs should always be considered when the ECG suggests RVOT-VT/PVCs and RF catheter ablation in the RVOT results in both a failed ablation and a change in QRS morphology. PA-VT/PVCs often originate from the septal side of the PA.     

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。     

特发性左室流出道室性心律失常的心电图特点

探讨特发性左室流出道室性心律失常患者的心电图特点。对 7例特发性左室流出道室性早搏 (简称室早 )、室性心动过速 (简称室速 )患者进行心电图分析 ,并行心内电生理检查及射频消融治疗 ,同时对 10例预激综合征患者成功消融房室旁道后行主动脉瓣上及瓣下起搏 ,记录同步 12导联起搏心电图。对比分析两组病例体表心电图QRS波图形特点。结果 :7例左室流出道室早、室速患者经心内电生理检查证实 6例起源于冠状动脉窦内 ,1例起源于左室流出道主动脉瓣右瓣下方 ,所有患者经射频消融成功治疗室性心律失常。对照组 10例在主动脉瓣下起搏(其中 6例同时在主动脉瓣上起搏 )获得同步 12导联起搏心电图。两组病例体表心电图共同特点为 :QRS波额面电轴向下 ,Ⅱ、Ⅲ、aVF导联主波向上 ,QRS波在V2 或V3 前移行为Rs或R型。结论 :左室流出道为特发性室早、室速发生部位之一 ,体表心电图有其独特性 ,导管射频消融治疗安全有效。     

左束支阻滞型特发性室性心动过速的心电图特征对射频消融成功的影响初探

对心电图呈左束支阻滞型的特发性室性心动过速 (简称室速 )的临床特点和心电图进行分析 ,以了解哪些因素可以预测此类患者从右室流出道行射频消融的成功率。对 2 6例特发性室速的患者进行电生理检查和射频消融手术 ,全部患者室速时的心电图呈左束支阻滞。结果 :2 6例中 ,2 2例于右室流出道进行了成功消融 ,成功和未成功消融的患者临床特征和电生理无明显区别 ,成功消融的患者中胸前V1 导联心电图呈rS型 (1 2例 )和QS型 (1 0例 ) ,而 4例未成功者 ,V1 导联均呈rS型 ,其中 2例经主动脉于左冠状窦消融成功。在成功与未成功消融患者中 ,V1 导联有无R波无明显区别 ,但V1 导联无R波预示室速可以从右室流出道成功消融 ,成功消融的室速患者胸前导联的平均移行区在V4导联 ,而未成功患者胸前导联的移行区在V3 或V2 导联。结论 :某些心电图呈左束支阻滞 ,且额面电轴正常或右偏的特发性室速患者不能成功从右室流出道消融 ,V1 导联有r波且移行区在V3 导联或之前者提示此类心电图特征的室速可能非起源于右室流出道 ,部分可能起源于左室流出道     

射频消融治疗起源于左室流出道的非持续性室性心动过速和频发性室性早搏

目的观察左室流出道非持续性室性心动过速（室速）和频发性室性早搏患者的射频消融治疗结果,探讨此类患者的射频消融指证。方法５例患者因非持续性室速和频发性室性早搏而引起明显临床症状,药物治疗无效。采用起搏标测法确定室速和室性早搏的起源部位,并射频消融治疗。结果在升主动脉瓣左窦下方的左室流出道记录到提前（３１±４）ｍｓ的心室激动,起搏心电图１２导联ＱＲＳ波形与室速和室性早搏形态完全相同者４例,１１导联相同者１例,该部位消融后５例患者的室速和室性早搏不被诱发。随访１３±６个月,除１例患者复发,另４例的临床症状明显改善。结论射频消融治疗左室流出道非持续性室速和室性早搏安全有效,但应严格掌握适应证。     

How to diagnose,locate, and ablate coronary cusp ventricular tachycardia

INTRODUCTION: Although radiofrequency energy usually is applied to the most favorable endocardial site in patients with outflow tract ventricular tachycardia, there are still some patients in whom the tachycardia can be ablated only from an epicardial site. We established the characteristics and technique of catheter ablation from both the left and right coronary cusps to cure left ventricular outflow tract ventricular tachycardia. METHODS AND RESULTS: We studied 15 patients in whom VT was thought to originate from the coronary cusp by both activation and pace mapping after precise mapping of the right ventricle, left ventricle, pulmonary artery, coronary cusps, and anterior interventricular vein. Twelve-lead ECG analysis revealed an S wave on lead I, tall R wave on leads II, III, and aVF, and no S wave on either lead V5 or V6. Precordial R wave transition occurred on leads V1 and V2. The earliest ventricular electrogram at a successful ablation site was recorded 35+/-12 msec before QRS onset and 19+/-15 msec earlier than the earliest ventricular electrogram recorded from the anterior interventricular vein. Almost identical pace mappings were obtained from the coronary cusp. Catheter tip temperature was maintained at 55 degrees C during energy delivery, and the distance from the tip to the ostium of each left and right coronary artery was > 1.0 cm by coronary angiography. CONCLUSION: Left ventricular outflow tract VT that could not be ablated from an endocardial site could be safely eliminated by radiofrequency application to the left and right coronary cusps.     

Ventricular tachycardias mimicking those arising from the right ventricular outflow tract

INTRODUCTION: Ablation of ventricular tachycardia (VT) arising from the right ventricular outflow tract (RVOT) has proven highly successful, yet VTs with similar ECG features may originate outside the RVOT. METHODS AND RESULTS: We reviewed the clinical, echocardiographic, and ECG findings of 29 consecutive patients referred for ablation of monomorphic VT having a left bundle branch block pattern in lead V1 and tall monophasic R waves inferiorly. Nineteen patients (group A) had VTs ablated from the RVOT, and 10 patients (group B) had VTs that could not be ablated from the RVOT. The QRS morphology during VT or frequent ventricular premature complexes was the only variable that distinguished the two groups. During the target arrhythmia, ECGs of group B patients displayed earlier precordial transition zones (median V3 vs V5; P < 0.001), more rightward axes (90 +/- 4 vs 83 +/- 5; P = 0.002), taller R waves inferiorly (aVF: 1.9 +/- 1.0 vs 2.4 +/- 0.5; P = 0.020) and small R waves in lead V1 (10/10 vs 9/19; P = 0.011). Radiofrequency catheter ablation from the RVOT failed to eliminate VT in any group B patient, but ablation from the left ventricular outflow tract (LVOT) eliminated VT in 2 of 6 patients in whom left ventricular ablation was attempted. CONCLUSION: The absence of an R wave in lead V1 and a late precordial transition zone suggest an RVOT origin of VT, whereas an early precordial transition zone characterizes VTs that mimic an RVOT origin. The latter VTs occasionally can be ablated from the LVOT. Recognition of these ECG features may help the physician advise patients and direct one's approach to ablation.