Catheter ablation of right ventricular outflow tract tachycardia: value of defining coronary anatomy

INTRODUCTION: Thermal damage to coronary arteries during catheter ablation has been previously reported. Coronary artery damage during LV outflow tract ventricular tachycardia is well recognized. However, the relationship of the coronary arteries to the RV outflow tract during catheter ablation has not been delineated. The purpose of this study was to define the relationship between the RV outflow tract and the coronary arteries utilizing arteriography, echocardiography, CT angiography, and gross anatomic pathology. METHODS: The relationship of the coronaries to the RV outflow tract was analyzed in three patients groups: Group 1: patients (n = 10) undergoing RV outflow tract ventricular tachycardia; Group 2: patients (n = 50) undergoing CT coronary angiography; Group 3: patients (n = 4) undergoing echocardiography during open heart surgery and intracardiac echocardiography (ICE) during catheter ablation of atrial fibrillation (n = 5). RESULTS: Group 1: The left main coronary artery was found to be 3.8 +/- 1.2 mm from the right ventricular outflow tract in patients undergoing ablation. Group 2: The minimum distance between the left main, left anterior descending, and right coronary artery to the RV outflow tract endocardial wall were 4.1 +/- 1.9 mm, 2.0 +/- 0.6 mm, and 4.3 +/- 1.9 mm (average +/- SD) respectively. Group 3: During open heart surgery using echocardiography, the minimum distance between the left main and the right coronary artery to the RV outflow tract were 3.4 +/- 0.35 mm and 2.0 +/- 0.1 mm, respectively. The distance between the let main coronary artery and the RVOT by ICE was 3.8 +/- 0.45 mm. CONCLUSIONS: The major coronary arteries lie in close proximity of the RVOT, and their anatomic course should be taken into consideration during ablation of ventricular tachycardias arising from the RV outflow tract.     

Damage to the left descending coronary artery due to radiofrequency ablation in the right ventricular outflow tract: Clinical case series and anatomical considerations

The purpose of this paper was to highlight the importance of the anatomy of the right ventricular outflow tract (RVOT) and the proximity of the mid segment of the left anterior descending coronary artery (LAD) to the RVOT in the setting of ablation of ventricular arrhythmias in the RVOT. During the period from 2014 till 2017, five patients with injury to the LAD during ablation within RVOT were identified in three centers, in Belgium, Germany and Israel. The clinical characteristics, procedural data and follow up data, where available, are reported. The literature review over coronary artery damage during radiofrequency ablation procedures is provided and the anatomy of the RVOT and the neighboring vascular structures is discussed. We present five patients who underwent radiofrequency ablation of ventricular arrhythmias mapped to the inferior and anterior part of the RVOT, at the insertion of the right ventricular wall to the septum, whereby ablation resulted in occlusion in four and severe stenosis in one, of the mid segment of the LAD coronary artery. All patients underwent percutaneous coronary intervention and stenting, four of them immediately during the same procedure and one 3 days later because of lack of signs and symptoms of acute coronary occlusion. In conclusion, the mid segment of the LAD at the level of the second septal perforator/second diagonal branch runs in very close proximity to the endocardial aspect of the lower part of the RVOT and care should be taken during ablation of ventricular arrhythmias in this region. Additional imaging such as intracardiac echocardiography and coronary angiography may be helpful in avoiding complications.     

射频导管消融特发性左心室流出道室性心动过速

目的 探讨特发性左心室流出道室性心动过速(室速)心电图特点及射频导管消融结果。方法 对5例未发现器质性心脏病的左心室流出道室速患者行12导联心电图、动态心电图、心内电生理检查及射频导管消融治疗。结果5例患者心电图Ⅱ、Ⅲ、aVF导联呈R波；Ⅰ导联呈rs或QS波，振幅大于0．5mV；V1导联呈rs或RS波，胸前导联R波移行发生于V2～V3；aVR和aVL导联呈QS波，3例患者的消融靶点在左冠状窦口内，2例位于主动脉瓣下，随访6个月，无1例复发。结论 左心室流出道室速有特殊心电图表现，射频导管消融是首选的治疗措施。     

Cryocatheter ablation of right ventricular outflow tract tachycardia

INTRODUCTION: Cryocatheter techniques have been successfully applied to treat supraventricular tachycardia but there are no reports on their value in treating ventricular tachycardia (VT). We present our initial experience with cryocatheter ablation of right ventricular outflow tract (RVOT) tachycardia. METHODS AND RESULTS: Cryocatheter ablation was attempted in 14 patients (13 females, age 45.9 +/- 12.7 years) who were highly symptomatic due to frequent monomorphic ventricular extrasystole (VES) or nonsustained VT originating within the RVOT. A 9-Fr, 8-mm-tip cryocatheter was used for both mapping and ablation. Cryoablation was started after localizing the arrhythmic focus by pace and activation mapping. Ablation success, defined by complete disappearance of target VES/VT acutely and during a follow-up of 9.3 +/- 1.4 weeks, was achieved in 13 of 14 patients. Ablation was successful with local activation times of 35 +/- 4 ms, 5.8 +/- 3.3 applications, 18.8 +/- 7.5 minutes total cryo time, 9.4 +/- 4.2 minutes fluoroscopy time, and 66.9 +/- 26.1 minutes total procedure time, the latter two measures showing a reduction with number of patients treated. Three patients reported slight pain related to local pressure of the catheter on the RVOT wall. No pain was described related to delivery of cryothermal energy. CONCLUSIONS: Initial experience shows that focal VES/VT originating in the RVOT can be successfully treated using cryocatheter ablation. Acute and short term success rates, fluoroscopy times, and duration of procedure are comparable to conventional ablation techniques. A major advantage seems to be the virtual absence of ablation related pain.     

Successful radiofrequency catheter ablation of epicardial left ventricular outflow tract tachycardia from the anterior interventricular coronary vein

We report a case of idiopathic left ventricular outflow tract (LVOT) tachycardia that was eliminated by a radiofrequency application from the anterior interventricular coronary vein (AIV). The ECG exhibited QRS complexes with an inferior axis and atypical left bundle branch block pattern with an early transition of the precordial R waves at V3. Several radiofrequency applications from the coronary cusps and endocardial LVOT were not effective. Radiofrequency applications in the AIV, where the activation preceded the onset of the QRS by 30 msec, successfully eliminated the tachycardia. The AIV may be an optional site for radiofrequency ablation of idiopathic epicardial LVOT tachycardia.     

Electrocardiographic features of failed and recurrent right ventricular outflow tract catheter ablation of idiopathic ventricular arrhythmias

1 Introduction

Various ECG algorithms have been proposed to identify the origin of idiopathic outflow tract (OT)‐ventricular arrhythmia (VA). However, electrocardiographic features of failed and recurrent right ventricular outflow tract (RVOT) ablation of idiopathic OT‐VAs have not been clearly elucidated.

2 Methods and results

A total of 264 consecutive patients (mean age: 44.0 ± 13.0 years, 96 male) undergoing RVOT ablation for OT‐VAs with a transition ≥V₃, including 241 patients (91.6%) with initially successful procedures and 23 patients (8.4%) with failed ablation. Detailed clinical characteristics and ECG features were analyzed and compared between the two groups. VAs with failed RVOT ablation had larger peak deflection index (PDI), longer V₂ R wave duration (V₂Rd), smaller V₂ S wave amplitude, higher R/S ratio in V₂, higher V₃ R wave amplitude, and larger V₂ transition ratio than those with successful ablation. Multivariate analysis demonstrated that PDI, V₂Rd, V₂ transition ratio, and pacemapping score acquired during mapping independently predicted failed ablation (P  =  0.01, P  =  0.01, P  =  0.01, and P < 0.001, respectively). In 31 recurrent cases (12.8%) after initially successful ablation, multivariate Cox regression analysis showed that only the earliest activation time acquired during mapping predicted the recurrences after successful ablation (P  =  0.001). The recurrent cases displayed different ECG features comparing with those with failed ablation.

3 Conclusion

The electrocardiographic features of failed RVOT ablation of idiopathic OT‐VAs with a transition ≥V₃ were characterized by PDI, V₂Rd, V₂ transition ratio, and pacemapping score acquired during mapping, unlike the recurrent RVOT ablation.     

Endocardial mapping of right ventricular outflow tract tachycardia using noncontact activation mapping

INTRODUCTION: Activation mapping and pace mapping identify successful ablation sites for catheter ablation of right ventricular outflow tract (RVOT) tachycardia. These methods are limited in patients with nonsustained tachycardia or isolated ventricular ectopic beats. We investigated the feasibility of using noncontact mapping to guide the ablation of RVOT arrhythmias. METHODS AND RESULTS: Nine patients with RVOT tachycardia and three patients with ectopic beats were studied using noncontact mapping. A multielectrode array catheter was introduced into the RVOT and tachycardia was analyzed using a virtual geometry. The earliest endocardial activation estimated by virtual electrograms was displayed on an isopotential color map and measured 33 +/- 13 msec before onset of QRS. Virtual unipolar electrograms at this site demonstrated QS morphology. Guided by a locator signal, ablation was performed with a mean of 6.9 +/- 2.2 radiofrequency deliveries. Acute success was achieved in all patients. During follow-up, one patient had a recurrence of RVOT tachycardia. Compared with patients (n = 21) who underwent catheter ablation using a conventional approach, a higher success rate was achieved by noncontact mapping. Procedure time was significantly longer in the noncontact mapping group. Fluoroscopy time was not significantly different in the two groups. CONCLUSION: Noncontact mapping can be used as a reliable tool to identify the site of earliest endocardial activation and to guide the ablation procedure in patients with RVOT tachycardia and in patients with ectopic beats originating from the RVOT.     

Arrhythmogenic right ventricular dysplasia presenting as right ventricular outflow tract tachycardia.

A case of a 51-year old male is presented. A left bundle branch block inferior axis tachycardia was manifest. At electrophysiological study this tachycardia was inducible and was ablated in the septal right ventricular outflow tract (RVOT). Two other tachycardias were identified both with right bundle branch block (RBBB) morphology raising the suspicion of diffuse pathology. Arrythmogenic right ventricular dysplasia (ARVD) was confirmed by right ventricular angiography and magnetic resonance imaging (MRI). An implantable cardioverter defibrillator (ICD) was implanted and an appropriate shock was later delivered.     

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。     

射频消融治疗右室流出道室性早搏的研究

目的 探讨射频消融治疗右室流出道室性早搏(RVOT-VPC)的临床效果和安全性.方法 经常规体检、生化检查、X线胸片、心脏彩超、心电图等各种检查后入院.右室流出道室性早搏患者48例,采用起搏标测法,以心室起搏时12导联心电图与其临床室性早搏的图形完全一致作为消融靶点,以放电后:①早搏在10s内消失;②出现同形早搏先增多...     

特发性左心室流出道心外膜侧室性心动过速

目的报道9例经电生理检查证实的特发性左心室流出道心外膜侧室性心动过速(室速)的体表心电图及电生理检查特点.方法男性5例,女性4例,年龄15～58岁,6例为运动诱发的持续性室速,3例为运动诱发的非持续性室速.结果室速时,9例体表心电图QRS波全部呈现右束支阻滞图形(8例胸前导联V1-V6呈现高R波),Ⅱ、Ⅲ、aVF导联为高R波,Ⅰ、aVL导联为QS波.电生理检查,右心室和左心室心内膜标测未发现最早心室激动点,在较早心室心内膜激动处的心内电图多呈现起始部低幅电位,提示远场电位.心室内起搏标测未发现与室速体表心电图12导联QRS波形态相同的起搏点.8例通过心脏静脉系统标测发现最早的心室激动点[体表心电图最早QRS波前15～50ms,平均(32±12)ms]和完全或近乎完全的起搏标测位于心大静脉的远端1例、心前间隔静脉的近端7例.1例患者在左心室流出道消融成功,1例患者在心大静脉远端血管内消融成功.其他患者在右心室和/或左心室内消融失败.结论心脏静脉标测可以鉴别出特发性左心室流出道心外膜侧室速.     

单导管指导下射频消融右心室流出道特发性室性心律失常

目的 探讨单导管标测指导下特发性右心室流出道(RVOT)频发室性早搏(VPC)、室速(VT)射频消融的有效性和安全性.方法 回顾性分析本中心2008年1月至2013年12月行单导管指导下射频消融治疗的特发性RVOT室早、室速患者共40例,男女比例1.0∶1.2,平均年龄(42.3±16.3)岁,发病时平均年龄(38.1±16.1)岁.结果 40例中单导管激动顺序标测和起搏标测确定起源于间隔部24例,游离壁16例.射频术中及术后均无并发症发生,手术即刻成功率为92.5％,随访(17.7±3.6)个月,复发6例(复发率16.2％),总成功率为77.5％.结论 特发性RVOT频发VPC、VT间隔部起源多于游离壁.单导管标测指导下射频消融RVOT室性心律失常有效、安全.     

射频消融治疗顽固性右心室流出道室性期前收缩

目的 :观察射频消融治疗右心室流出道室性期前收缩 (VPB)的疗效。方法 :12例频发右心室流出道VPB患者 ,动态心电图示VPB数 (2 4 786± 72 2 7)个 /2 4h ,VPB相关的临床症状重 ,服用多种抗心律失常药物无效或不能耐受。采用起搏标测法确定VPB的起源部位 ,行射频消融治疗。结果 :10例起搏标测记录到与自发VPBQRS形态 12导联一致的波形 ,消融成功 ,成功部位在右室流出道间隔部 7例、游离壁 3例。另 2例只记录到 11导联一致的波形 ,消融失败。成功率为 83.3%。成功病例术后 1周复查动态心电图示VPB(2± 3)个 /2 4h ;随访 5～ 15个月 ,复查动态心电图示VPB(4± 11)个 /2 4h ,无复发病例 ,无并发症发生。结论 :导管射频消融治疗右心室流出道VPB疗效好、安全性高 ,可供临床症状重、药物治疗效果不好患者选择     

右室流出道室性期前收缩的心电图特征及射频消融治疗

目的:探讨右室流出道室性期前收缩(室性早搏,室早)的心电图特征和评价单导管法消融单形性右室流出道室性早搏的有效性、安全性和实用性。方法:对52例心脏结构正常的右室流出道单形性室早的心电图特征进行分析并行单导管射频消融。采用起搏标测法,以起搏时与自发室性早搏形态波形态完全相同点为消融靶点。结果:右室流出道的室性早搏体表12导联心电图特征,呈完全性左束支阻滞形态,Ⅰ导联呈rs、m、QS及R型,aVR、aVL均呈QS型,Ⅱ、Ⅲ、aVF、V5~6导联均呈单向R波型,胸前导联R波移行区常在V3、V4导联之后。成功消融结果显示26例室早起源右室流出道间隔部:其中前间隔7例、中间隔5例、后间隔14例,游离壁21例:其中前游离壁6例、后游离壁15例,希氏束附近1例,肺动脉瓣下1例。消融即刻成功率94%(49/52),未成功的3例。手术操作时间30~150 min,X线曝光时间5~29 min。术后随访2~48个月无复发。结论:起源于右室流出道的室性早搏有其独特的心电图表现,单导管射频消融可有效、安全地消融心脏结构正常的右室流出道单形性室性早搏。     

采用心内非接触式标测的右心室流出道室性心动过速的射频消融

目的 右心室流出道(right ventricular outflow tract,RVOT)的解剖结构使得对该部位的室性心动过速(ventricular tachyeardia,VT,室速)标测定位的难度较大,远期成功率也较低,为此,采用心内非接触式标测指导导管消融。方法 20例患者(男性12例,女性8例),年龄14～59(35.1±12.3)岁。其中6例有晕厥或黑矇史,7例既往曾接受射频消融未获成功。全部患者均在RVOT内放置EnSite3000标测导管,在窦性心律下进行疤痕标测和心动过速时进行最早激动标测,并根据标测结果使用EnSite 3000导管的导航功能指导消融定位。消融前并进行起搏标测。结果 20例患者共诱发出22种RVOT室速,其中3例还伴其它起源的室性早搏(室早)。疤痕标测提示,13例患者有电学意义上的疤痕区域,且有11例室速起源于该疤痕区域。25个室速或室早起源点中1例起源于近肺动脉瓣口部,10个位于间隔侧,其余均偏游离壁,其中7个偏RVOT后壁中、下部,4个偏前壁中、下部,3个位于游离壁侧;病变基质的直径为6～42 mm,平均(16.8±9.2)mm。非接触式标测所确定的最早激动处电位平均领先体表20～62(41.0±13.8)ms;与自发的室性心动过速相比,起搏标测下14例的12个导联QRS形态完全一致,11/12个导联一致的为10例,1例有10/12导联一致。全部室速和室早均消融成功。在标测确定的     

Electrocardiographic determinants of the polymorphic QRS morphology in idiopathic right ventricular outflow tract tachycardia

Coupling Intervals and Polymorphic QRS Morphologies . Introduction: Premature ventricular contractions (PVCs) arising from the right ventricular outflow tract (RVOT) can trigger polymorphic ventricular tachycardia (PVT) or ventricular fibrillation (VF) in patients with no structural heart disease. We aimed to clarify the ECG determinants of the polymorphic QRS morphology in idiopathic RVOT PVT/VF. Methods and Results: The ECG parameters were compared between 18 patients with idiopathic PVT/VF (PVT‐group) and 21 with monomorphic VT arising from the RVOT (MVT‐group). The coupling interval (CI) of the first VT beat was comparable between the 2 groups. However, the prematurity index (PI) of the first VT beat was smaller in the PVT‐group than in the MVT‐group (P < 0.001). Furthermore, the QT index, defined as the ratio of the CI to the QT interval of the preceding sinus complex, was also smaller for the PVT/VF in the PVT‐group than that for the VT in the MVT‐group (P < 0.01). In the PVT‐group, the CI of the first VT beat was comparable between that of VT and isolated PVCs, but the PI of the first VT beat was shorter for VT than isolated PVCs (P < 0.05). The PI was the only independent determinant of the polymorphic QRS morphology (odd ratio = 2.198; 95% confidence interval = 1.321–3.659; P = 0.002). Conclusion: The smaller PIs of the first VT beat may result in a polymorphic QRS morphology. (Cardiovasc Electrophysiol, Vol. 23, pp. 521‐526, May 2012)     

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.