Catheter ablation of stable and unstable ventricular tachycardias in patients with arrhythmogenic right ventricular dysplasia

INTRODUCTION: A reentrant circuit within an area of abnormal myocardium is suspected as the origin of ventricular tachycardia (VT) in patients with arrhythmogenic right ventricular dysplasia (ARVD). OBJECTIVES: To examine the relationship between the reentrant circuits of VT and the abnormal electrograms in ARVD, and to assess the feasibility of a block line formation in the reentrant circuit isthmus utilizing electroanatomical mapping system (CARTO) guidance. METHODS AND RESULTS: An electrophysiological study and catheter ablation (CA) were performed in 17 ARVD patients (13 men, 47 +/- 17 year) using CARTO. Endocardial mapping during sinus rhythm demonstrated electrogram abnormalities extended from the tricuspid annulus (TA) or the right ventricular outflow tract in 16 of 17 patients. In 13 hemodynamically stable VTs, the reentrant circuits and critical slow conduction sites for the CA were investigated during VTs. The entire macro-reentrant pathway was identified in 6/13 stable VTs (figure-of-8 in 4, single loop in 2). In the remaining seven VTs, a focal activation pattern was found in four and an unidentifiable pattern in three. CA successfully abolished all the macro-reentrant and focal tachycardias, however, not effective in three unidentifiable VTs. In the 13 cases with unstable VT, the linear conduction block zone was produced between the sites with abnormal electrograms and the TA. Ultimately, 23/26 VTs (88%) became noninducible after the CA. During follow-up (26 +/- 15 months), 13/17 patients remained free from any VT episodes. CONCLUSIONS: CARTO is useful for characterizing the anatomical and electrophysiological substrates, and for identifying the optimal ablation sites for VT associated with ARVD.     

动态基质标测在致心律失常右室心肌病患者室性心动过速射频消融中的应用

目的　探讨应用非接触球囊导管标测系统行动态基质标测,指导对致心律失常右室心肌病(ARVC)患者室性心动过速(室速)消融的价值。方法　应用非接触球囊导管标测系统在窦律下对 3例ARVC室速患者行动态基质标测,在确定室速的最早激动点、出口部位和传导顺序后,寻找与室速相关的峡部并行线性消融。结果　3例患者存在 3种不同形态的基质,分别位于右室流出道、右室前壁和右室前侧壁。共诱发 5种室速,平均心动周期为(348±65)ms,其中 3种室速起源于基质或基质边缘, 2种室速的起源远离基质; 1种室速经基质传导。5种室速全部消融成功。平均随访 20个月,无心动过速发作。结论　应用非接触球囊导管标测系统确定异常电生理基质有助于理解ARVC室速的发生机制和制定消融策略,行室速相关峡部的线性消融可有效治疗室速。     

Ventricular tachycardia mapping and ablation in arrhythmogenic right ventricular cardiomyopathy/dysplasia:Lessons Learned

Arrhythmogenic right ventricular cardiomyopathy/dysplasia(ARVC/D) is primarily believed to be an inherited cardiomyopathy that subsequently results in significant myocardial fibrosis. The arrhythmogenic consequences that result from the development of fibrosis are similar to other nonischemic cardiomyopathies, but the unique endocardial-epicardial disease process of ARVC/D requires a specialized approach for arrhythmia treatment in the electrophysiology laboratory. Although the association between ARVC/D and development of ventricular arrhythmias has become increasingly clear over the last 2 decades, our understanding of the arrhythmia mechanisms, underlying electrophysiologic substrate, and treatment strategies were significantly limited. Prospective studies performed in the electrophysiology laboratory allowed detailed characterization of the electrophysiologic and electroanatomic substrate underlying ventricular tachycardia in patients with ARVC/D. Thishas allowed clinician scientists to better characterize the arrhythmia mechanism and develop the necessary strategies to perform successful catheter ablation. Early in this experience, catheter ablation was considered a limited and largely unsuccessful treatment for patients experiencing painful and recurrent defibrillator therapy. Through our increased understanding of the disease process, catheter ablation has evolved to become an effective and preferred therapy for a majority of these patients. Our understanding of the disease and necessary approaches to provide successful treatment continues to evolve as the clinical experience grows. This article will review these important insights from the electrophysiology laboratory and how application of this knowledge has facilitated the development of a methodical approach to successfully perform ventricular tachycardia ablation in patients with ARVC/D.     

Bundle branch reentry ventricular tachycardia in arrhythmogenic right ventricular dysplasia

A 42-year-old male had history of recurrent palpitation and was documented to have wide QRS tachycardia. Magnetic resonance imaging angiogram showed evidence of arrhythmogenic right ventricular dysplasia and severe right ventricular dysfunction. Electrophysiology study showed evidence of bundle branch reentry ventricular tachycardia. It was successfully treated by radiofrequency ablation of right bundle branch. This is probably the first case of bundle branch reentry as a mechanism for ventricular tachycardia in a case of arrhythmogenic right ventricular dysplasia.     

A case of arrhythmogenic right ventricular dysplasia with ventricular fibrillation

A case of repeated attacks of ventricular fibrillation is described. The patient suffered from an arrhythmogenic right ventricular dysplasia (ARVD) documented by right and left ventriculograms and myocardial biopsies obtained during surgical treatment of the arrhythmia. The histological changes were interpreted as being signs of fresh myocardial damage of unknown origin in addition to a replacement of the normal myocardium by adipose and fibrotic tissue. The repeated attacks of ventricular fibrillation in this patient contrast to the arrhythmia spectrum noted in the available literature on ARVD, mostly stable chronic ventricular tachycardias.     

致心律失常性右室心肌病室性心动过速的射频消融治疗

目的评价致心律失常性右室心肌病(ARVC)室性心动过速(VT)射频消融的疗效。方法 4例ARVC患者,男3例,女1例,年龄27～62岁,均有反复头昏、心悸、晕厥或黑矇病史。4例患者症状发作时共出现6种形态的VT,频率为130～210次/分。在三维标测系统(CARTO或EnSite Array)指导下行VT消融治疗。结果 4例患者共行6次手术,其中3次采用CARTO系统,3次采用EnSiteArray系统指导。3例完成消融,随访2～19个月,3例患者均无猝死、晕厥或黑矇发生;2例术后一周内复发,但VT的频率减慢,药物能有效控制,术后5～6个月VT不再发作。另1例患者在放电消融过程中VT的频率加快,形态紊乱,蜕变为心室颤动,紧急电复律后转为窦性心律,终止手术。随访6个月,无VT发生。结论致心律失常性右室心肌病VT的射频消融治疗可改善病人的症状。     

三维标测指导致心律失常性右心室心肌病室性心动过速的射频消融

目的介绍致心律失常性右心室心肌病（ARVC）室性心动过速（室速）的三维标测方法及其消融策略。方法21例ARVC室速患者,因1—4种抗心律失常药物治疗无效,临床上呈反复发作、无休止发作或植入型心律转复除颤器（ICD）植入后频繁放电治疗,接受导管消融治疗。其中,男性19例,女性2例,平均年龄（32±12）岁。9例患者接受电解剖（Carto）标测,12例患者接受非接触标测（EnSite—Array）。在首先明确病变基质的基础上,通过激动标测、拖带标测及起搏标测,分析心动过速的起源、可能的传导径路及其出口以及它们与病变基质的关系。通常于心动过速的出口处及其周边行局灶消融,术中病变基质周边的延迟激动电位应一并消融。结果21例患者,2例呈无休止发作,1例患者表现为频繁室性早搏及加速性室性自主心律,余18例患者消融中共诱发出34种心动过速。所有心动过速均呈左束支阻滞形,平均心动过速周长为（289±68）ms。16例患者（28种室速）消融治疗即刻成功,3例患者（7种室速）部分成功,2例患者（2种室速）消融失败,即刻消融成功率76．2％。所有患者消融术后继续服用抗心律失常药物。平均随访6～30（1d±7）个月,成功患者中2例复发,其中1例再次消融成功;未达即刻成功的5例患者,经抗心律失常药物治疗后,均无室性心律失常事件发生,其中包括1例消融后植入ICD者。结论三维标测系统可首先明确ARVC患者的病变基质,在此基础上结合激动标测和心内各种电刺激技术,可直观显示心动过速的起源、缓慢传导区出口及折返环路,以此制定消融策略可成功治疗ARVC室速。心动过速起源于心肌深部或ARVC病变进展,是消融失败和复发的常见原因。     

Multiple exercise induced syncopal episodes in a young woman due to arrhythmogenic right ventricular dysplasia.

A case of a young woman with multiple exercise induced syncopal episodes due to arrhythmogenic right ventricular dysplasia is described. The report emphasizes the importance of exercise induced syncope and the management is described.     

Electroanatomic mapping characteristics of ventricular tachycardia in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia.

BACKGROUND: Ventricular tachycardia (VT) in arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVD) has been previously explored using entrainment mapping techniques but little is know about VT mechanisms and the characteristics of their circuits using an electroanatomical mapping system. METHODS AND RESULTS: Three-dimensional electroanatomical mapping was performed in 11 patients with well tolerated sustained VT and ARVD. Sinus rhythm mapping of the right ventricle was performed in eight patients showing areas of low bipolar electrogram voltage (<1.2 mV). In total 12 tachycardias (mean cycle length 382+/-62 ms) were induced and mapped. Complete maps demonstrated a reentry mechanism in eight VTs and a focal activation pattern in four VTs. The reentrant circuits were localized around the tricuspid annulus (five VTs), around the right ventricular outflow tract (one VT) and on the RV free lateral wall (two VTs). The critical isthmus of each peritricuspid circuit was bounded by the tricuspid annulus with a low voltage area close to it. The isthmus of tachycardia originating from the right ventricular outflow tract (RVOT) was delineated by the tricuspid annulus with a low voltage area localized on the posterior wall of the RVOT. Each right ventricular free wall circuit showed an isthmus delineated by two parallel lines of block. Focal tachycardias originated on the right ventricular free wall. Linear radiofrequency ablation performed across the critical isthmus was successful in seven of eight reentrant tachycardias. The focal VTs were successfully ablated in 50% of cases. During a follow-up of 9-50 months VT recurred in four of eight initially successfully ablated VTs. CONCLUSIONS: Peritricuspid ventricular reentry is a frequent mechanism of VT in patients with ARVD which can be identified by detailed 3D electroanatomical mapping. This novel form of mapping is valuable in identifying VT mechanisms and in guiding RF ablation in patients with ARVD.     

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.     

致心律失常性右室心肌病的CARTO系统电生理基质标测和射频导管消融

目的应用CARTO系统对致心律失常性右室心肌病(ARVC)患者进行电解剖标测并指导射频消融治疗其室性心动过速(简称室速)。方法入选伴有室速反复发作的25例ARVC患者,年龄36±12岁,男性17例,有家族成员35岁以下早发猝死史3例。术前行常规心电图、心室晚电位、心脏B超检查。在窦性心律或/和心动过速时,电解剖标测三维重建右室。术中6例同时行右室造影检查。根据双极电图电压高低确定疤痕区、正常心肌和临界边缘区。对于折返性室速,线性消融关键峡部或疤痕区与三尖瓣环之间或两疤痕区间;对于局灶性室速,点消融局部最早激动区域。结果 20%(5/25)体表心电图发现前壁或下壁导联Epsilon波,心室晚电位阳性占88%(21/25),心脏B超发现右室不同程度的局部或整体扩张,56%(14/25)可见局部囊袋状向外膨出。所有患者均出现1～5(2±1)种左束支阻滞型室速,其中5例合并频发室性早搏,1例伴心房扑动,1例伴左后间隔旁道。即时消融成功率为72%(18/25)。随访14±10(4～36)个月,原消融成功的5例室速复发。1例消融失败伴晕厥史的患者植入ICD治疗。无手术相关并发症和死亡发生。结论应用CARTO系统电解剖标测可安全有效指导射频消融治疗ARVC患者的室速,有相对较高的失败和复发率。CARTO系统标测的电压图,参考术前心电图、心脏B超及右室造影可了解病变心肌的分布范围,对初步确定室速的病理基质有帮助。     

Quantitative analysis of the signal-averaged QRS in patients with arrhythmogenic right ventricular dysplasia

Temporal signal averaging of the surface QRS (VI + V3 + V5)was performed in 16 patients with arrhythmogenic right ventriculardysplasia and in 16 normal subjects. The differences betweenARVD patients and normals were large for the filtered QRS duration(FQRSd) (146.2±18.9 vs. 91.8±4.1ms, P<000001),the late potential duration (LPd) (83.5±23.3 ms vs. 23.6±4.6ms,P< 0.00001), the LPd/ FQRSd ratio (53.9± 10.1% vs.25.8±5.1%, P <0.00001), the filtered QRS amplitude(234.0±61.1µV vs. 429±942 fiV, P <0001),and the root mean square voltage of the signals in the terminal40 and 50 ms of the FQRS (RMS40 and RMS50) (18.4± 10.0µVvs. 118.4±49.8p.V, P<0.0005 and 27.9± 19.2µVvs. 217.0±66.3fiV, P<0000002). RMS50 <40µVdiscriminated best between ARVD and normals (81% sensitivityand 100% specificity). The right-sided predominance of the abnormalitiesin ARVD was demonstrated by the significantly longer FQRSd andLPd, and the higher ratio LPd/FQRSd in right than in left precordialleads. The arrhythmia susceptibility did not seem to influencethe presence of or properties ofLP in the ARVD group. Patientswith multiple QRS morphologies during ventricular tachycardia(VT) had, compared with patients with only one type of VT, longerLPd (108.3 ±46.4 ms vs. 64.2 ±31.7 ms, P<0.02)and lower RMS40 voltage (9.4±9.9 µV vs. 25.4±21.6µV, P<0.05). The relative heart volume was positivelycorrelated with delayed activity, but an enlarged heart wasnot apre-requisitefor the presence ofLP. The method thus identifieschanges which are specific to ARVD. The findings indicate thatcertain electrical or morphological conditions are requiredfor the occurrence of arrhythmias.     

非接触心内膜球囊标测系统指导瘢痕相关性室性心动过速标测和消融

目的 运用非接触心力膜球囊标测系统（EnSite3000系统）对瘢痕相关性室性心动过速（室速）进行心内膜标测，探讨瘢痕相关性室速电生理机制。标测和消融。方法 运用非开胸法建立心肌梗死后持续性单形性室速猎模型4只；同时选取致心律失常性右室心肌病（ARVC）合并室速患者2例，于左心室或左，右心室内各置入-EnSite3000球囊，分别构建左和（或）右心室的三维几何模型。确定心内膜瘢痕组织的部位，范围和边界，分析单形性室速的激动顺序，关键部位和折返环路及与瘢痕组织的关系，并制定消融策略指导消融。结果 （1）EnSite3000系统准确标测出4只猪左心室心梗后瘢痕组织，其部位，大小及边缘等均与病理一致。4只猪共诱发出8种形态的单形性室速，系统标测出2种室速为左心室典型的“8”字形折返途径，1种室速最早激动点位于左心室前侧壁瘢痕边缘。通过双心室球囊放置准确标测到2只猪5种形态室速在双心室内的激动路径，所有室速的关键位点均在瘢痕组织边缘或其中，6种室速位于左室，2种室速位于右室，可成功释放电流的3种室速消融有效，1种室速线性消融失败；4种室速因放电仅几秒钟即出现凡室颤动，且反复出现，使消融难以完成因而未获成功。（2）2例ARVC患者的右心室流出道处均可标测到类似瘢痕组织的低电压区，1例患者诱发出2种类型的折返性室速，均消融成功，随访4个月无室速发作；另1例患者2种室速，消融失败后置入心脏复律除颤器。结论 EnSite3000系统能准确标测到常规方法无法标测的室速相关性低电压区或瘢痕区域，确定瘢痕相关性室速的机制和关键位点，并精确导航，有助于提高瘢痕相关性室速的消融成功率，为此类室速的消融提供了较好的标测手段。如能结合消融方法和能源的改善，可望进一步提高这类室速的消融成功率。     

室性心动过速的基质标测与消融

目的 探讨使用Carto三维系统标测致心律失常性右心室心肌病(ARVD/C)室性心律失常的基质来指导导管消融的安全性和有效性.方法 自2007年7月至2008年4月,北京大学第一医院心内科连续收治4例ARVD/C患者,年龄28～53岁,男性3例,女性1例,其中1例患者有直系亲属猝死家族史,发作性室性早搏/室性心动过速(VT)病史3个月至24年.使用Carto三维系统进行电解剖电压标测,局部电压低于1.5 mV的区域判断为病变心肌,低于0.5 mV的区域为瘢痕区,结合传统的激动顺序标测、起搏标测、拖带标测和心室内碎裂电位,识别病变心肌范围和心动过速折返路径以指导消融.结果 4例患者电生理检查共诱发出7种形态的左束支阻滞形、VT,电解剖电压标测的低电压区主要位于右心室流人道的基底部和偏间隔部,在病变心肌与正常心肌交界区和/或环绕病变心肌的最早激动处做线性消融,4例患者均获消融即刻成功,无并发症.4例患者消融术后随访3个月至1年,有1例出现复发,口服胺碘酮控制,至今无晕厥和猝死.结论 ARVD/C的VT标测与消融安全可靠,应用三维系统进行电解剖电压标测与传统的心电标测方式相结合,可更精确判断ARVD/C的室性心律失常基质和有效提高消融成功率.     

Newly diagnosed arrhythmogenic right ventricular dysplasia in an octogenarian

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is thought to be a disease of the young, with the majority of newly diagnosed patients under 40 years of age. Establishing this diagnosis in elderly patients may be challenging, and a few reports exist of patients older than 70 years diagnosed with ARVD/C at autopsy. We report the case of an octogenarian with antemortem newly diagnosed ARVD/C. This case report represents the oldest patient to date to have a newly established diagnosis of ARVD/C and highlights the difficulty in making the diagnosis in the elderly.     

Misdiagnosis of arrhythmogenic right ventricular dysplasia/cardiomyopathy

INTRODUCTION: Diagnosis of arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) has major implications for the management of patients and their first-degree relatives. Diagnosis is based on a set of criteria proposed by the International Task Force for Cardiomyopathies. We report our experience in providing a re-evaluation for patients who previously have been diagnosed with ARVD/C. METHODS AND RESULTS: We studied 89 patients who requested a re-evaluation for diagnosis of ARVD/C at our center. Each of these patients had been diagnosed with ARVD/C at their initial evaluation. Each patient was re-evaluated with clinical history, physical examination, and noninvasive testing at our center. Invasive testing, which included electrophysiologic testing, right ventricular angiography, and endomyocardial biopsy, was performed when clinically indicated. Sixty (92%) of the 65 patients who had undergone magnetic resonance imaging (MRI) at an outside institution were reported to have an abnormal MRI consistent with ARVD/C. Among these patients, the only abnormality identified was the qualitative finding of intramyocardial fat/wall thinning in 46 patients. On re-evaluation, these qualitative findings were not confirmed. None of these 46 patients ultimately were diagnosed with ARVD/C. Among the entire patient group, only 24 (27%) of the 89 patients met the Task Force criteria for ARVD/C. CONCLUSION: This study demonstrates that the high frequency of "misdiagnosis" of ARVD/C is due to over-reliance on the presence of intramyocardial fat/wall thinning on MRI, incomplete diagnostic testing, and lack of awareness of the Task Force criteria. Diagnosis of ARVD/C cannot rely solely upon qualitative features on MRI.     

Clinical outcomes of catheter ablation of ventricular tachycardia in patients with arrhythmogenic right ventricular cardiomyopathy: Insights from the Johns Hopkins ARVC Program

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