Successful radiofrequency ablation of adenosine-sensitive right ventricular outflow tract tachycardia

We report on a patient without evidence of structural heartdisease who presented with adenosine-sensitive sustained ventriculartachycardia with left bundle branch block and right axis QRSmorphology. Endocardial catheter mapping revealed the originof ventricular tachycardia to be located in the right ventricularoutflow tract, where the earliest endocardial activation duringventricular tachycardia was registered 30–40 ms priorto onset of QRS complex in the surface ECG. Pacemapping providedno additional information; we found a good match between 12lead surface ECGs registered during spontaneous episodes ofventricular tachycardia and those recorded during pacing ina relatively large area in the right ventricular outflow tract.The 10th application of radiofrequency current abolished ventriculartachycardia temporarily, but it recurred within 30 min. Afterthe 28th radiofrequency current delivery ventricular tachycardiawas permanently abolished.     

Clinical and electrophysiological differences between patients with arrhythmogenic right ventricular dysplasia and right ventricular outflow tract tachycardia.

AIMS: Radiofrequency catheter ablation is considered first line treatment for symptomatic patients with right ventricular outflow tract tachycardia (RVOT). The role of ablation in arrhythmogenic right ventricular dysplasia (ARVD) is more limited. As such, differentiating between the two conditions is essential. METHODS AND RESULTS: This study compared non-invasive findings, magnetic resonance images (MRI), invasive electrophysiological characteristics, results of ablation and long-term outcome in 50 consecutive patients with RVOT (33) or ARVD (17). Structural abnormalities were uniform in the ARVD group; in addition 18 (54%) of the RVOT tachycardia group had MRI abnormalities. At electrophysiological study the tachycardia in the ARVD group displayed features of re-entry in over 80%, but behaved with a triggered automatic basis in 97% with RVOT. Ablation was complete or partial success in 12 (71%) patients with ARVD and ventricular tachycardia (VT) recurred in eight (48%). In the RVOT patients, ablation was a complete success in 97% with recurrent VT in 6%. Long-term success in the RVOT patients was 95% in both patients with and without MRI abnormalities. CONCLUSIONS: Electrophysiological characterization can differentiate ARVD from RVOT. The finding of abnormalities on MRI does not have any bearing on arrhythmia mechanism, acute or long-term success of RFA.     

食管心房调搏终止室性心动过速的初步探讨

目的：总结15例经食管心房调搏，成功终止室性心动过速的经验与体会。方法：选择15例室性心动过速病人，予以食管心房调搏，先后用分级递增和连续递增两种刺激方式予以刺激，刺激电压为25～30V，对难以终止，静脉注射异搏定，再予以经食管心房调搏。结果：单纯采用分级递增法终止了10例患的室速，2例患需加用连续递增法才能终止，另3例患经上述两种方式均未成功，给予异搏定5mg静脉注射后以分级递增法才终止了室速。结论：经食管心房起搏可以部分地成功终止持续性室性心动过速，减少直流电复律应用的必要性。     

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.     

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.     

体表心电图鉴别心室流出道特发性室性心动过速的起源部位

目的 :评价 12导联心电图在鉴别左室和右室流出道室性心动过速 (VT)及鉴别左室流出道VT中主动脉瓣上起源的VT和主动脉瓣下起源的VT中的价值。方法 :回顾性分析了射频消融术获得成功的 5 6例流出道特发性VT患者体表心电图特点 ,右室流出道VT组 (RVOT VT)组 4 0例 ,左室流出道VT(LVOT VT)组 16例 ,其中主动脉瓣上组 (左冠窦内 ) 10例 ,主动脉瓣下组 6例。结果 :LVOT VT组胸前导联R波移行均早于V4导联 ,87.5 %(14 / 16 )在V1或V2 导联 ,RVOT VT组 82 .5 % (33/ 4 0 )胸前导联R波移行≥V4导联 ,无一例在V3 导联前移行 ;RVOT VT组V1和V2 导联R波时限指数和R/S波幅指数明显小于LVOT VT组 [(30 .4± 12 .6 ) %∶(5 7.4± 14 .2 ) %和 (13.8± 7.5 ) %∶(5 8.2± 11.4 ) % ,均P <0 .0 1]。主动脉瓣上LVOT VT组下壁导联 (Ⅱ ,Ⅲ ,aVF)R波振幅明显高于主动脉瓣下组 ;V5和V6导联或单独V6导联有s波对确定主动脉瓣下起源的LVOT VT敏感性 10 0 % (6 / 6 ) ,V5和V6导联均无s波对确定主动脉瓣上起源的LVOT VT特异性 90 % (9/ 10 )。结论 :体表心电图对初步确定心室流出道VT的起源部位可以提供很大的帮助。     

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.     

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.     

Remote magnetic navigation for mapping and ablating right ventricular outflow tract tachycardia

BACKGROUND: Navigation, mapping, and ablation in the right ventricular outflow tract (RVOT) can be difficult. Catheter navigation using external magnetic fields may allow more accurate mapping and ablation. OBJECTIVES: The purpose of this study was to assess the feasibility of RVOT tachycardia ablation using remote magnetic navigation. METHODS: Mapping and ablation were performed in eight patients with outflow tract ventricular arrhythmias. Tachycardia mapping was undertaken with a 64-polar basket catheter, followed by remote activation and pace-mapping using a magnetically enabled catheter. The area of interest was localized on the basket catheter in seven patients in whom an RVOT arrhythmia was identified. Remote navigation of the magnetic catheter to this area was followed by pace-mapping. Ablation was performed at the site of perfect pace-mapping, with earliest activation if possible. RESULTS: Acute success was achieved in all patients (median four applications). Median procedural time was 144 minutes, with 13.4 minutes of patient fluoroscopy time and 3.8 minutes of physician fluoroscopy time. No complications occurred. One recurrence occurred during follow-up (mean 366 days). CONCLUSION: RVOT tachycardias can be mapped and ablated using remote magnetic navigation, initially guided by a basket catheter. Precise activation and pace-mapping are possible. Remote magnetic navigation permitted low fluoroscopy exposure for the physician. Long-term results are promising.     

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     

低能量放电下标测无室性早搏的流出道室性心动过速

目的 本文报道11例非频发室性早搏(室早)的流出道室性心动过速(室速)伴反复晕厥病例经导管射频消融成功的体会,并由此介绍一种新的针对这类患者的标测方法.方法 11例患者,全部为女性,年龄(39.9±13.7)岁,全部曾使用2种以上抗心律失常药物治疗,治疗期间均有晕厥或黑矇病史1～3年.结果 (1)所有11例患者在术中经过各种方法均可记录到至少1次室早、室速发作心电图,其中6例经程序刺激不能诱发的通过静脉滴注异丙肾上腺素能诱发室早、室速.(2)所有患者先在右心室流出道预测起源区以15～20 W低能量放电下微调消融电极导管位置和方向,在诱发出与所记录、冻结的室早完全一致的位点时,加大能量至35～50 W,反复巩固2～3次,直至室早、室速不再出现.然后以此点为中心,向周围微移动电极导管约5 mm,最终消融出大约1 cm2的面积.所有11例患者,采用这种方法全部都诱发出与记录室早12/12导联完全一致的室速.(3)11例患者中有10例达到消融终点,其中9例在右心室流出道间隔部及后壁,1例在右冠窦基底部.另1例未达到消融终点的患者,在消融开始时用异丙肾上腺素仅可诱发极少的室早,但在低能量消融后诱发频发的短阵室速,激动标测提示最早激动点位于左冠窦中下部,该处放电诱发出与自发室早一致的图,但反复放电室早、室速不能完全消除,考虑为靠外膜区室早而放弃.(4)术后所有患者经电话、预约门诊随访3～14个月,没有1例主诉再发黑矇和晕厥者.结论 低能量放电标测完全可作为一种新的标测手段在实际工作中配合使用,尤其对那些反复黑矇、晕厥但室早、室速发作较少的患者,常规标测方法几乎无用,此时低能量放电标测就显得更加实用.     

Tachycardia induced tachycardia: case report of right ventricular outflow tract tachycardia and AV nodal reentrant tachycardia

Tachycardia induced tachycardia, or so called double tachycardia, is rare. A 34 year old woman is described who had a history of syncope, frequent extrasystoles, and episodes of non-sustained ventricular tachycardia, perceived as palpitation, without syncope. At electrophysiological study, during infusion of isoprenaline, an episode of non-sustained ventricular tachycardia arising from the right ventricular outflow tract initiated sustained atrioventricular nodal reentrant tachycardia, thought to be the cause of the patient's syncope. Ablation of the right ventricular outflow tract focus abolished the ventricular ectopy; the slow AV nodal pathway was also ablated. The patient no longer has either syncope or palpitation.     

Evaluation and management of ventricular outflow tract tachycardias

Ventricular tachycardia (VT) arising from the right or left ventricular outflow tract (OT) is a recognized arrhythmia in individuals with structurally normal hearts. Treatment options for OTVT include medications, ablation and, rarely, an implantable cardioverter defibrillator (ICD). In the past few years ablation techniques have developed to the point where most OTVTs can be successfully ablated. However, a percentage of cases have remained where ablation is unsuccessful. Some of these cases may represent an epicardial focus of the VT. Several approaches to epicardial VT ablation have been described. We recently described a LVOT-VT variant, which may be epicardial in nature, in a group of patients in whom prior ablation attempts had failed. A trans-aortic ablation approach to outflow tract VT was successful in these patients.     

心室流出道室性心动过速模型的构建

目的构建特发性流出道室性心动过速(简称室速)的动物模型。方法选择新西兰大白兔20只,随机分为室速组和对照组,每组10只。通过高频(50ms,5.0V)刺激心外膜主动脉与肺动脉交界处,导致室速的发生。实验结束后立即取出左右流出道心肌组织,采用免疫组化方法检测酪氨酸羟化酶染色阳性的交感神经纤维,观察其形态、分布及密度变化,其密度采用阳性纤维或结构在选区中的面积比表示。结果 10只兔6只诱发出流出道室速;室速组兔左、右流出道心室肌组织神经分布与对照组不同,其密度明显增高(P0.05)。结论心外膜主动脉与肺动脉交界处高频刺激可诱发流出道室速的发生。     

Intermittent capture of the right ventricular outflow tract by atrial pacing in a patient with a dual-chamber pacemaker

We describe a previously unreported phenomenon of intermittent outflow right ventricular tract capture from the atrial lead of a dual-chamber pacemaker. This was more obvious at slower paced atrial rates and disappeared by decreasing the atrial pulses voltage. Electroanatomical mapping showed that the onset of activation was nearly simultaneous at the insertion site of the atrial lead and at an intermediate level of the right ventricular outflow tract. This exceptional finding might be erroneously diagnosed as due to pseudo-pseudo fusion beats.     

Electrocardiographic (ECG) clues to differentiate idiopathic right ventricular outflow tract tachycardia (RVOTT) from arrhythmogenic right ventricular cardiomyopathy (ARVC)

Introduction

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a genetic cardiomyopathy that most commonly affects young adults. The most commonly observed reason of death in patients suffering from ARVC/D is sudden cardiac death (SCD). On the other hand, idiopathic right ventricular outflow tract tachycardia (RVOT VT) usually has a benign course. Both of the entities may have ventricular tachycardia (VT) with left bundle branch block (LBBB) pattern and inferior axis. We tried to propose new discriminating electrocardiographic indices for differentiation of foretold entities.

Material and method

This was a retrospective study. We reviewed records of patients admitted between 2003 and 2012 with the diagnosis of either ARVC/D or RVOT VT that presented with VT (LBBB morphology).

Result

A total of fifty nine patients (30 RVOT VT and 29 ARVC/D) were enrolled. In ARVC/D group, men were dominant while the reverse was true of RVOT VT. Palpitation was more common in the RVOT VT group (90% vs. 66.7%), but aborted SCD and sustained VT were more common in ARVC/D group. The new ECG criteria proposed by us mean QRS duration in V1–V3, QRS difference in right and left precordial leads, S wave upstroke duration, JT interval dispersion, QRS and JT interval of right to left precordial leads were all significantly longer in ARVC/D when compared to RVOT VT patients (p < 0.001).

Conclusion

The proposed ECG criteria can be used for non-invasive diagnosis of ARVC/D and incorporation in the future updates of ARVC/D task force criteria.