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.     

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.     

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.     

致心律失常性右心室心肌病的造影诊断

目的 评价心血管造影术(angiocardiography,ACG)对致心律失常性右心室心肌病(arrhythmogenicright ventricular cardiomyopathy,ARVC)的诊断价值和限度.方法 对11例临床确诊ARVC的患者行左心室、右心室造影,观察其形态及运动功能(特别是漏斗流出道、心尖小梁部以及下壁).结果 11例均行右心室造影,形态上表现为漏斗流出道扩张,其中7例为局限性扩张,3例为局限性扩张并囊袋状突出,1例为局限性扩张并叠盘状影;心尖小梁部8例叠盘状影,2例囊袋状突出,1例叠盘状影并囊袋状突出;下壁9例囊袋状突出,1例叠盘状影,1例囊袋状突出并叠盘状影.在运动功能异常方面,运动减弱最明显,分别见于漏斗流出道8/11,心尖小梁部10/11,下壁10/11;其次为无运动,分别发生在漏斗流出道2/11,心尖小梁部1/11,下壁1/11.1例还另行左心室造影,表现为:小梁粗大,心尖囊袋状突起,切迹,室间隔光滑.结论 右心室造影,征象明确,只要抓住发育不良三角形态及功能变化,就能作出正确诊断.ACG是ARVC诊断和鉴别诊断的重要依据.     

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.     

Long-term follow-up in patients with arrhythmogenic right ventricular cardiomyopathy

Long‐Term Prognosis in Patients with ARVC. Introduction: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a major cause of sudden cardiac death due to tachyarrhythmias. The purpose of this study was to investigate the long‐term prognosis in patients with ARVC and the incidence of rapid ventricular arrhythmias during follow‐up. Methods: Thirty ARVC patients (19 male, 63.3%, mean age 48 ± 15 years) fulfilling modified Task Force criteria 2010 were included. Of them, 13 patients (43.3%) received implantable cardioverter‐defibrillator (ICD) implantation. Rapid ventricular arrhythmia was defined as electrical storm or the occurrence of ventricular tachycardia (VT) or ventricular fibrillation (VF) with a cycle length of 240 ms or less that necessitate shock delivery to 2 or more times within a 24‐hour period. Results: With a mean follow‐up of 68 ± 10 months, 6 patients (20%) with ICD implantation had recurrent rapid VT/VF. One (3.3%) of them died of multiple shocks and SCD, and 5 (16.7%) had multiple ICD therapies due to VT/VF and electrical storm. The interval between the diagnosis of ARVC and occurrence of rapid VT/VF was 13.4 ± 4.9 months. Most (5/6, 83.3%) events of recurrent rapid VT/VF occurred within 2 years. Ablated patients who did not receive an ICD implant were totally free of rapid VT/VF. Conclusions: For patients with ARVC, long‐term prognosis is favorable. During a long‐term follow‐up, patients meeting the criteria for ICD implantation have a higher rate of rapid and potentially life‐threatening arrhythmias. However, early and clustered recurrence of rapid VT/VF in patients with an ICD is common, whereas late occurrence of rapid VT/VF is very rare. (J Cardiovasc Electrophysiol, Vol. 23, pp. 750‐756, July 2012)     

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.     

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.     

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.     

Catheter ablation of ventricular tachycardia in arrhythmogenic right ventricular dysplasia

Arrhythmogenic right ventricular dysplasia (ARVD) is a progressive, genetically determined fibro-fatty infiltrative myocardial disease with an estimated prevalence in the general population to be 1:5,000 to 1:10,000. ARVD leads to electrical instability that may predispose to life-threatening ventricular arrhythmia, heart failure, and sudden death. We reviewed the pathological substrate for ventricular arrhythmias, ECG findings and treatment modalities in ARVD. Importantly, novel techniques such as electroanatomic and voltage mapping has greatly improved the identification of the scared substrate in the settings of ARVD and have improved safety and efficacy of VT ablation procedures associated with this entity.     

致心律失常性右室心肌病高危患者相关危险因素分析

目的探讨致心律失常性右室心肌病(ARVD/C)高危患者相关危险因素。方法根据1994年ARVD/C诊断标准,纳入43例ARVD/C先证者。分组标准:有晕厥病史并记录到室性心动过速(简称室速)为高危病人;记录到室性早搏(简称室早)、室速但无晕厥病史及其他临床情况定为低危病人。收集参数包括:①心电图V1～3QRS波时限≥110 ms、V1～3导联S波升支时限≥55 ms、Epsilon波、T波倒置、(V1+V2+V3)/(V4+V5+V6)QRS波时限≥1.2、QRS波离散度≥40 ms、QT离散度≥65 ms;②信号平均心电图记录晚电位参数;③Holter记录室早或室速;④超声记录双房、双室及右室流出道、流入道内径大小。Logistic回归分析高危患者ARVD/C病人的相关危险因素。结果心室晚电位阳性、右室射血分数<0.40与高危ARVD/C显著相关。结论晚电位阳性、右心功能不全是ARVD/C的高危因素。     

Changes in the isolated delayed component as an endpoint of catheter ablation in arrhythmogenic right ventricular cardiomyopathy: predictor for long-term success

Introduction: Although successful ablation of ventricular tachycardia (VT) is feasible in arrhythmogenic right ventricular cardiomyopathy (ARVC), long-term recurrence is common. The aim of this study was to assess the usefulness of a change in the isolated delayed component (IDC) as an endpoint of the catheter ablation in ARVC.
Methods and Results: Eighteen patients (48 ± 11 years) with ARVC were studied. Detailed endocardial mapping of the right ventricle (RV) was performed during sinus rhythm. IDCs were recorded in 16 patients and the latest IDCs were related to the VT circuit. Catheter ablation was carried out in the areas with the IDCs. At the end of the session, the IDC was electrically dissociated in one, disappeared in five, exhibited second-degree block in one, was significantly delayed (≥50 ms) in three, and remained unchanged in six. The change in the IDC was correlated with the change in the type II/III late potentials in the signal-averaged electrocardiography (ECG) and the inducibility of the clinical VT after the ablation. During a follow-up of 61 ± 38 months, VT recurred in six. The patients with a changed IDC had a significantly lower VT recurrence than those with no IDC or an unchanged IDC (P < 0.02).
Conclusion: In patients with ARVC, (1) the IDCs during sinus rhythm are related to the clinical VT and can be a target for the ablation, (2) a change in the IDC can be used as an endpoint, and (3) qualitative analyses of the serial signal-averaged ECGs may be useful for the long-term follow-up.     

Reader- and instrument-dependent variability in the electrocardiographic assessment of arrhythmogenic right ventricular dysplasia/cardiomyopathy

Variability in ECG Assessment in ARVD/C . Introduction: Despite the use of standardized definitions, widely varying prevalence estimates of electrocardiographic (ECG) features related to arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) have been reported in different cohorts. This study was aimed at examining the variability in the ECG interpretation resulting from the same reader, different readers, and using different ECG‐resolutions. Methods and Results: Blinded to other clinical data, 2 readers examined quantitative and qualitative ECG features of 20 (10 ARVD/C) randomly selected individuals. ECGs were recorded at standard‐speed (SS) and double‐speed‐double‐amplitude (DS) settings. The SS ECGs were scanned, magnified 4×, and evaluated using electronic calipers (EL). One reader repeated all measurements. For both readers, the intraclass correlation coefficient (ICC) for the measurement of QRS duration was good between conventional and electronic evaluation [DS vs EL: Reader 1—0.64 (0.52–0.73); Reader 2—0.67 (0.55–0.76)][SS vs EL: Reader 1—0.60 (0.47–0.70); Reader 2—0.60 (0.47–0.70)]. Using the same resolution, the intrareader ICC was good for SS [0.70 (0.59–0.78)], DS [0.85 (0.80–0.90)], and EL [0.70 (0.69–0.83)] resolutions, but deteriorated for interreader comparisons [0.50 (0.36–0.62), 0.75 (0.66–0.82), and 0.75 (0.66–0.82), respectively]. For qualitative parameters, the intra‐ and interreader agreement was inconsistent for all but 2 parameters. Both readers were in perfect agreement while interpreting right precordial T‐wave inversion [κ= 1] and right bundle branch block morphology (RBBB) [κ= 0.83 (0.5–1.0)] even when using SS resolution. Conclusions: Right precordial t‐wave inversion and RBBB are the only ECG parameters that can be detected consistently even using the conventionally used ECG‐resolution. The substantial variability in evaluation of other parameters is not improved even with the use of higher resolutions. (J Cardiovasc Electrophysiol, Vol. 22, pp. 561‐568 May 2011)     

Thromboembolic complications in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy.

AIMS: Incidence and clinical presentation of thromboembolic complications in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) were analysed. In reports on ARVD/C, thromboembolism is rarely mentioned. The possible risk factors are: right ventricle (RV) dilatation, aneurysms, and wall motion abnormalities. METHODS AND RESULTS: A group of 126 patients (89 male, 37 female, aged 43.6+/-14.3) with ARVD/C was retrospectively analysed for the presence of thromboembolic complications. The mean follow-up period was 99+/-64 months. Thromboembolic complications, i.e. pulmonary embolism (n=2), RV outflow tract thrombosis with severe RV failure (n=1), and cerebrovascular accident associated with atrial fibrillation (n=2) were observed in 4% of the patients. Spontaneous echogenic contrast was observed in seven patients with severe damage to RV. In four of them supraventricular arrhythmias resulting in heart failure were reported. Annual incidence of thromboembolic complications was 0.5/100 patients. CONCLUSIONS: (i) ARVD/C may be complicated by thrombosis. Annual incidence of such complications is significantly lower than reported for left ventricle failure. (ii) Anticoagulation should be used in ARVD/C patients with large, hypokinetic RV and slow blood flow. (iii) Patients with severe forms of ARVD/C, thrombus formation in the RV and/or spontaneous echocardiographic contrast are at higher risk of a poor outcome.     

A casual spontaneous mutation as possible cause of the familial form of arrhythmogenic right ventricular cardiomyopathy (arrhythmogenic right ventricular dysplasia).

In a family affected by arrhythmogenic right ventricular cardiomyopathy (ARVC) the familial occurrence was investigated. All 14 members of two generations were investigated carefully, and only 2 (father and one son) members were affected. Both subjects had a massive form of the disease with relevant ventricular arrhythmias. Apart from the limitations of having investigated few subjects, this behavior suggests a genetic mutation appearing in the father and transmitted via an autosomal dominant trait.     

Ablation of ventricular tachycardia by isolating the critical site in a patient with arrhythmogenic right ventricular cardiomyopathy

We describe a patient with arrhythmogenic right ventricular cardiomyopathy in whom ventricular tachycardia (VT) was ablated by isolating a relatively large area of the critical site using catheter ablation. Endocardial mapping showed abnormal fragmented electrograms with delayed potential (DP) from an entire area of the aneurysm. Pace mappings from the aneurysm produced a QRS morphology identical to that of clinical VT. After catheter ablation was performed at the exit site of the VT critical area, programmed stimulation inside the aneurysm captured the DP but not the QRS complexes. These data suggest that VT can be ablated successfully by isolation of the critical area.