Arrhythmogenic right ventricular cardiomyopathy/dysplasia: An update

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a genetic cardiomyopathy characterized by ventricular arrhythmias and structural abnormalities of the right ventricle (RV). The diagnosis is based on the International Task Force criteria. Cardiologists may not be aware of these diagnostic criteria for ARVC/D and may place too much importance on the results of MRI imaging of the right ventricle. Patients with ARVC/D usually have an abnormal 12-lead electrocardiogram, abnormal echocardiogram, and ventricular arrhythmias with a left bundle branch block morphology. If noninvasive testing suggests ARVC/D, invasive testing with an RV angiogram, RV biopsy, and electrophysiologic study is recommended. Once a diagnosis of ARVC/D is established, the main treatment decision involves whether to implant an implantable cardioverter-defibrillator. We also recommend treatment with β blockers. Patients with ARVC/D are encouraged to avoid competitive athletics. Recent advances in the understanding of the genetic basis of ARVC/D have revealed that ARVC/D is a disease of desmosomal dysfunction.     

Arrhythmogenic right ventricular cardiomyopathy: From genetics to diagnostic and therapeutic challenges

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic disease characterized by myocyte loss and fibro-fatty tissue replacement. Diagnosis of ARVC remains a clinical challenge mainly at its early stages and in patients with minimal echocardiographic right ventricular (RV) abnormalities. ARVC shares some common features with other cardiac diseases, such as RV outflow ventricular tachycardia, Brugada syndrome, and myocarditis, due to arrhythmic expressivity and biventricular involvement. The identification of ARVC can be often challenging, because of the heterogeneous clinical presentation, highly variable intra- and inter-family expressivity and incomplete penetrance. This genotype-phenotype “plasticity” is largely unexplained. A familial history of ARVC is present in 30% to 50% of cases, and the disease is considered a genetic cardiomyopathy, usually inherited in an autosomal dominant pattern with variable penetrance and expressivity; in addition, autosomal recessive forms have been reported (Naxos disease and Carvajal syndrome). Diagnosis of ARVC relays on a scoring system, with major or minor criteria on the Revised Task Force Criteria. Implantable cardioverter defibrillators (ICDs) are increasingly utilized in patients with ARVC who have survived sudden death (SD) (secondary prevention). However, there are few data available to help identifying ARVC patients in whom the prophylactic implantation of an ICD is truly warranted. Prevention of SD is the primary goal of management. Pharmacologic treatment of arrhythmias, catheter ablation of ventricular tachycardia, and ICD are the mainstay of treatment of ARVC.     

MR Imaging of arrhythmogenic right ventricular cardiomyopathy: morphologic findings and interobserver reliability

BACKGROUND: Magnetic resonance (MR) imaging is frequently used to diagnose arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). However, the reliability of various MR imaging features for diagnosing ARVC/D is unknown. The purpose of this study was to determine which morphologic MR imaging features have the greatest interobserver reliability for diagnosing ARVC/D. METHODS: Forty-five sets of films of cardiac MR images were sent to 8 radiologists and 5 cardiologists with experience in this field. There were 7 cases of definite ARVC/D as defined by the Task Force criteria. Six cases were controls. The remaining 32 cases had MR imaging because of clinical suspicion of ARVC/D. Readers evaluated the images for the presence of (a) right ventricle (RV) enlargement, (b) RV abnormal morphology, (c) left ventricle enlargement, (d) presence of high T(1) signal (fat) in the myocardium, and (e) location of high T(1) signal (fat) on a Likert scale with formatted responses. RESULTS: Readers indicated that the Task Force ARVC/D cases had significantly more (chi(2) = 119.93, d.f. = 10, p < 0.0001) RV chamber size enlargement (58%) than either the suspected ARVC/D (12%) or no ARVC/D (14%) cases. When readers reported the RV chamber size as enlarged they were significantly more likely to report the case as ARVC/D present (chi(2)(= )33.98, d.f. = 1, p < 0.0001). When readers reported the morphology as abnormal they were more likely to diagnose the case as ARVC/D present (chi(2) = 78.4, d.f. = 1, p < 0.0001), and the Task Force ARVC/D (47%) cases received significantly more abnormal reports than either suspected ARVC/D (20%) or non-ARVC/D (15%) cases. There was no significant difference between patient groups in the reported presence of high signal intensity (fat) in the RV (chi(2) = 0.9, d.f. = 2, p > 0.05). CONCLUSIONS: Reviewers found that the size and shape of abnormalities in the RV are key MR imaging discriminates of ARVD. Subsequent protocol development and multicenter trials need to address these parameters. Essential steps in improving accuracy and reducing variability include a standardized acquisition protocol and standardized analysis with dynamic cine review of regional RV function and quantification of RV and left ventricle volumes.     

Right ventricular scar‐related ventricular tachycardia in nonischemic cardiomyopathy: Electrophysiological characteristics,mapping, and ablation of underlying heart disease

1 Background

Right ventricular (RV)‐scar related ventricular tachycardia (VT) is often due to arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) or cardiac sarcoidosis (CS), but some patients whose clinical course has not been described do not fulfill diagnostic criteria for these diseases. We sought to characterize the electrophysiologic substrate and catheter ablation outcomes of such patients, termed RV cardiomyopathy of unknown source (RCUS).

2 Methods and results

Data of 100 consecutive patients who presented with RV cardiomyopathy and/or RV‐related VT for ablation were reviewed (51 ARVC/D, 22 CS; 27 RCUS). Compared to ARVC/D, RCUS patients were older (P = 0.001), less commonly had RV dilatation (P = 0.001) or dysfunction (P = 0.01) and fragmented QRS, parietal block, and T‐wave inversion. Compared to CS, R‐CUS patients had less severe LV dysfunction. Extent and distribution of endocardial/epicardial scar and inducible VTs in RCUS patients were comparable with ARVC/D and CS patients. At a median follow‐up of 23 months, RCUS patients had more favorable VT‐free survival (RCUS 71%, ARVC/D 60%, CS 41%, P = 0.03) and survival free of death or cardiac transplant (RCUS 92%, ARVC/D 92%, CS 62%, P = 0.01). No RCUS patients developed new criteria for ARVC/D or CS in follow‐up.

3 Conclusions

Up to one‐third of patients with RV scar‐related VT are not classifiable as ARVC/D or CS. These patients had a somewhat better prognosis than ARVC/D or sarcoid and did not develop evidence of these diseases during the initial 2 years of follow‐up. The extent to which this population comprises mild ARVC/D, CS, or other diseases is not clear.     

Arrhythmogenic right ventricular cardiomyopathy: three cases

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a rare disease characterized by replacement of myocardium with fibrofatty tissue. It mainly involves the right ventricle (RV) and causes abnormal RV performance. ARVC is the most common cause of sudden cardiac death in young Italian athletes because it induces malignant ventricular tachyarrhythmias. Clinical manifestations of ARVC may be different between Chinese and Western patients. In this paper, we share our experience of the clinical manifestations of ARVC and review previous reports of ARVC.     

Arrhythmogenic right ventricular cardiomyopathy: current diagnostic and management strategies

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a heart muscle disease of unknown etiology characterized by the peculiar right ventricular (RV) involvement. Distinctive pathologic features are myocardial atrophy and fibro-fatty replacement of the RV free wall, and clinical presentation is usually related to ventricular tachycardias with a left bundle branch block pattern or ventricular fibrillation leading to cardiac arrest, mostly in young people and athletes. Later in the disease evolution, progression and extension of RV muscle disease and left ventricular involvement may result in right or biventricular heart failure. The diagnosis of ARVC may be difficult because of several problems with specificity of ECG abnormalities, different potential etiologies of ventricular arrhythmias with a left bundle branch morphology, assessment of RV structure and function, and interpretation of endomyocardial biopsy findings. Therefore, standardized diagnostic criteria have been proposed by the Study Group on ARVC of the European Society of Cardiology. According to these guidelines, the diagnosis of ARVC is based on the presence of major and minor criteria encompassing electrocardiographic, arrhythmic, morphofunctional, histopathologic, and genetic factors. Since the assessment of sudden death risk in patients with ARVC is still not well established, there are no precise guidelines to determine which patients need to be treated and what is the best management approach. The therapeutic options include beta-blockers, antiarrhythmic drugs, catheter ablation, and implantable cardioverter defibrillator (ICD). The ICD is the most effective safeguard against arrhythmic sudden death. However, its precise role in changing the natural history of ARVC by preventing sudden and nonsudden death needs to be evaluated by a prospective study of a large series of patients. In patients in whom ARVC has progressed to severe RV or biventricular systolic dysfunction with risk of thromboembolic complications, treatment consists of current therapy for heart failure including anticoagulant therapy. In cases of refractory congestive heart failure, patients may become candidates for heart transplantation.     

Diagnostic value of endomyocardial biopsy guided by electroanatomic voltage mapping in arrhythmogenic right ventricular cardiomyopathy/dysplasia

Introduction: To improve the endomyocardial biopsy (EMB) diagnostic sensitivity for arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D), we hypothesized a biopsy sampling focused on selected right ventricle (RV) low‐voltage areas identified by electroanatomic voltage mapping. Methods and Results: The study population (22 patients, 10 men; mean age 34 ± 10 years) included 11 patients with overt ARVC/D (group A) and 11 patients with suspected ARVC/D (group B), according to both arrhythmic profile and standardized noninvasive diagnostic criteria. In all 22 patients, an RV bipolar voltage mapping was performed with CARTO? system sampling multiple endocardial sites (262 ± 61), during sinus rhythm, with a 0.5–1.5 mV color range setting of voltage display. All 11 (100%) group A patients and 8 of the 11 (73%) group B patients (P = nonsignificant [NS]) presented RV low‐voltage areas (<0.5 mV). In 8 group A patients and in all 8 group B patients with a pathological RV voltage map, an EMB focused on the low‐voltage areas was performed. In 6 (75%) group A patients and in 7 (87%) group B patients (P = NS), voltage mapping‐guided EMB was diagnostic for ARVC/D. In the remaining 3 patients, only nonspecific histological findings were observed. Conclusions: The results of our study (1) confirm the high diagnostic sensitivity of RV voltage mapping in patients with overt ARVC/D, (2) document a high prevalence of RV low‐voltage areas even in patients with suspected ARVC/D, and (3) demonstrate that in patients with clinical evidence or suspicion for ARVC/D, presenting RV low‐voltage areas, EMB guided by voltage mapping may provide ARVC/D diagnosis confirmation.     

Do patients with right ventricular outflow tract ventricular arrhythmias have a normal right ventricular wall motion? A quantitative analysis compared to normal subjects

BACKGROUND/AIM: Patients with ventricular ectopy from the right ventricular (RV) outflow tract (RVOT) are often referred for RV angiography to exclude disorders such as arrhythmogenic RV cardiomyopathy/dysplasia (ARVC/D). This is usually based on a qualitative assessment of the wall motion. We present a method to quantify the wall motion and to apply this method to compare patients with RVOT ectopy to normal subjects. METHODS: RV angiograms were analyzed from 19 normal subjects and 11 subjects with RVOT ventricular arrhythmias (RVOT arrhythmia subjects) who had no other clinical or other evidence for ARVC/D. By a newly developed computer-based method, RV contours were first traced from multiple frames spanning the entire cardiac cycle. The fractional change in area between contours was then calculated as a serial function of time and location to determine both total contour area change and timing of contour movement. Contour area strain, defined as the differential change in area between nearby regions, was also computed. RESULTS: The contour area change was greatest in the tricuspid valve region and least in the RVOT and midanterior regions. The onset of contraction was earliest in the RVOT region and latest in the apical, inferior, inferoapical, and subtricuspid valve regions. The contour strain was largest in superior tricuspid valve and inferior wall and near zero within the lateral tricuspid valve region. There were significant pairwise differences in contraction area, timing, and strain in the various regions. There were no significant differences between normal subjects and RVOT arrhythmia subjects. CONCLUSIONS: The RV wall motion is nonuniform in contour area change, strain, and timing of motion. Patients with RVOT ventricular ectopy demonstrate wall motion parameters similar to those of normal subjects. This technique should be applicable in analyzing RV wall motion in patients suspected of having ARVC/D.     

Right atrial abnormalities in a patient with arrhythmogenic right ventricular cardiomyopathy without ventricular tachycardia

We describe a 59-year-old woman with sick sinus syndrome (SSS) and arrhythmogenic right ventricular cardiomyopathy (ARVC). Diagnosis of SSS was made because she had frequent episodes of sinus arrest with prolonged ventricular asystole. Cardiac images showed a dilated right atrium (RA) and a right ventricle (RV). Electroanatomical mapping of the RA showed extensive scarring with no recordable electrical potentials. Although she had frequent premature ventricular contractions, neither spontaneous ventricular tachycardia (VT) nor induced VT was observed. Microscopic examination of the RV indicated fibrofatty myocardium. Atrial arrhythmias associated with SSS may be the cause of symptoms in some cases of ARVC.     

Endomyocardial biopsy guided by electroanatomic voltage mapping in arrhythmogenic right ventricular cardiomyopathy: a case report

A positive endomyocardial biopsy (EMB) is a major diagnostic criterion for arrhythmogenic right ventricular cardiomyopathy (ARVC). Nevertheless, its sensitivity is low due to the focal nature of the disease. Moreover, myocardial samples are usually taken from the uncommonly involved interventricular septum to minimize the risk of perforation. In this report, we describe a novel bioptical approach for ARVC diagnosis guided by the identification of right ventricle (RV) affected regions by means of electroanatomical voltage mapping.     

Patients with Scar-Related Right Ventricular Tachycardia: Determinants of Long-Term Outcome

Introduction: Patients with established arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) based on task force (TF) criteria and ventricular tachycardia (VT) are at risk of VT recurrence and sudden death. Data on patients with VT due to right ventricular (RV) scar not fulfilling TF criteria are lacking. The purpose of this study was to assess the long-term arrhythmia recurrence rate and outcome in patients with scar-related right VT with and without a diagnosis of ARVC/D.
Methods: Sixty-four patients (age 43.5 ± 15 years, 49 males) presenting with nonischemic scar-related VT of RV origin were studied. Scar was identified by electroanatomical mapping, contrast echocardiography, and/or magnetic resonance imaging (MRI). Patients were evaluated and treated according to a standard institute protocol.
Results: Twenty-nine (45%) patients were diagnosed with ARVC/D according to TF criteria (TF+) and 35 (55%) with RV scar of undetermined origin (TF–) at the end of follow-up (64 ± 42 months). Patients were treated with antiarrhythmic drugs, radiofrequency catheter ablation, and/or implantable cardioverter-defibrillator (ICD) implantation. VT recurrence-free survival for TF+ and TF– was 76% versus 74% at 1 year and 45% versus 50% at 4 years (P = ns). Patients with fast index VT (cycle length [CL]≤ 250 ms, n = 31) were more likely to experience a fast VT during follow-up than patients with a slow index VT (CL > 250 ms, n = 33) (61% vs 3%, P < 0.001).
Conclusions: Scar-related RV VTs have a high recurrence rate in TF+ and TF– patients. Patients presenting with a fast index VT are at high risk for fast VT recurrence and may benefit most from ICD therapy.     

Arrhythmogenic right ventricular cardiomyopathy

Arrythmogenic right ventricular (RV) cardiomyopathy (ARVC) is a cardiomyopathy characterized pathologically by fibrofatty replacement primarily of the RV and clinically by life-threatening ventricular arrhythmias in apparently healthy young people. The prevalence of the disease has been estimated at 1 in 5,000 individuals, although this estimate will likely increase as awareness of the condition increases among physicians. Arrythmogenic RV cardiomyopathy is recognized as a cause of sudden death during athletic activity because of its association with ventricular arrhythmias that are provoked by exercise-induced catecholamine discharge. Diagnosis may be difficult because many of the electrocardiographic abnormalities mimic patterns seen in normal children, and the disease often involves only patchy areas of the RV. For this reason, international diagnostic criteria for ARVC were proposed by an expert consensus panel in 1996. Treatment is directed to preventing life-threatening cardiac arrhythmias with medications and the use of implantable defibrillators. This article will present in detail the etiology, clinical presentation, diagnosis and management of this condition.     

磁共振成像在致心律不齐性右室型心肌病的诊断价值

目的回顾性分析27例致心律不齐性右室型心肌病（ARVC）的磁共振成像（MRI）表现,探讨MRI在ARVC的诊断与预后判断中的价值。方法按照1994年WHO关于ARVC的诊断标准,2004年10月至2006年6月共27例临床诊断或病理确诊为ARVC（6例行心脏移植术）,男21例,女6例,平均年龄37．4（15～67）岁。采用1．5T超导MRI扫描仪对心脏形态（脂肪浸润、房室大小）、功能（室壁局部与整体运动功能）、心肌灌注与心肌存活等方面进行综合评价。结果形态学：88．89％（24／27）的病例MRI提示心肌脂肪浸润,62．96％（17／27）右室壁变薄,62．96％（17／27）右室心尖肌小梁明显粗乱,66．67％（18／27）右室流出道扩张,51．85％（14／27）右室心尖扩张,66．67％（18／27）右室下壁及游离壁扩张,40．74％（11／27）合并右房增大。心脏功能：18．52％（5／27）的病例右室局部运动功能异常,70．37％（19／27）整体运动功能异常,右室平均射血分数（EF）35％。40．74％（11／27）的患者合并左室扩大并室壁收缩运动明显减弱。心肌首过灌注示10．52％（2／19）的患者左室受累,36．84％（7／19）的患者左室和右室壁出现异常强化,提示心肌纤维或胶原变性。右室壁强化区域主要位于右室游离壁和右室流出道肌壁,左室则主要位于左室侧壁,少数合并左室心尖或室间隔,5例左室侧壁异常强化经术后病理证实为纤维组织。仅1例表现为右室流出道增宽,但左室心肌显著变薄,收缩运动明显减弱;有3例右室MRI无阳性表现,其中2例左室侧壁室壁变薄并运动异常,延迟显像为异常强化,另1例表现为类似扩张型心肌病样改变。结论MRI高度的软组织对比与多序列成像可对ARVC进行全面诊断与预后评价,但少数以左室异常表现为主而无明显或仅轻微右室异常的病例,MRI易误诊,其左室侧壁段的纤维化为ARVC相对特征表现。右室整体运动异常、广泛纤维脂肪浸润、合并左室扩张并运动异常为其预后不良的指标。     

Epsilon Waves as an Extreme Form of Depolarization Delay: Focusing on the Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia

Revision of the Task Force diagnostic criteria (TFC) for arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D), in 2010, has increased the sensitivity for the diagnosis of early and familial forms of the disease. Epsilon wave (EW) is a major diagnostic criterion in the context of ARVC/D, however, it remains unquantifiable and therefore, may leave room for substantial subjective interpretation, thus, explaining the existing high inter-observer variability in the assessment of EW. EW, when present, coexists with other disease characteristics, which are sufficient for ARVC/D diagnosis, making EW generally not required for ARVC/D diagnosis. Nevertheless, EW remains an important part of the electrocardiographic phenotype of ARVC/D that may be useful in planning diagnostic work-up, which needs to be recognized.     

新型磁共振对典型及早期致心律失常性右室心肌病诊断价值的探讨

目的 用有黑血技术的新型磁共振（MRI）对典型致心律失常性右室心肌病（ARVC）进行检查，以确定新型MRI诊断ARVC的特异性和敏感性，并通过对确诊的ARVC患的一级亲属行MRI检查，以探讨MRI对早期ARVC的诊断价值。方法 10例ARVC患（除1例猝死首诊外）及其7个家系的54名成员全部接受询问病史，体检，心电图，心脏超声等检查；10例临床患均接受MRI检查，分析和确定其影响特征及诊断条件，在此基础上对部分家系成员行MRI检查以发现早期ARVC患。结果 临床患有阵发性室性心动过速（8／8），晕厥（9／10），心力衰竭（3／10）和猝死（3／10）。心电图均有左束支传导阻滞型阵发性室性心动过速，心室晚电位（VLP）均阳性（8／8）。MRI检查显示临床患均有明显右心室（RV）扩大及室壁广泛强信号，经压脂处理后心肌信号呈岛状或连续中断，为特征性纤维脂肪替代影像，患均有RV运动减低或室壁瘤形成，部分伴左心室受累（3／8）。家系筛选发现8例异常，拟诊为早期ARVC，2例有心电图异常，2例VLP阳性。MRI显示，8例心室壁均有局限性纤维脂肪病的影像改变，4例有RV扩大，2例可疑扩大，6例RV心尖部血流淤滞现象。结论 带黑血技术的新型MRI是目前诊断ARVC和早期ARVC的最具特异性和敏感性的检查手段。     

Relative Utility of Magnetic Resonance Imaging and Right Ventricular Angiography to Diagnose Arrhythmogenic Right Ventricular Cardiomyopathy

INTRODUCTION: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is characterized by fibrofatty replacement of the RV myocardium. Two imaging techniques used to assess patients suspected of having ARVC are magnetic resonance imaging (MRI) and right ventricular angiography (RVA). Traditionally, RVA has played a central role in the diagnosis of ARVC, but the non-invasive nature of MRI and its unique ability to detect fatty tissue infiltration has increased its popularity as a diagnostic tool. The objective of this study was to assess the relative diagnostic accuracy of MRI and RVA for ARVC. METHODS AND RESULTS: Seventeen patients (9 men, 8 women; ages 42 +/- 17 [range 16-78] years) with documented ventricular arrhythmias were investigated for ARVC. A positive diagnosis of ARVC was based on criteria set forth by the ISFC Working Group on Cardiomyopathies and Dysplasia. ECG-gated spin-echo and gradient-echo MR images in multiple planes and RAO/LAO RV angiograms were compared for diagnostic concordance. Based on working group criteria, 7 patients were diagnosed with ARVC. In ten patients, MRI suggested ARVC. The remaining 7 patients had no MRI findings suggestive of the disease. Four patients with MRI findings of ARVC were incorrectly diagnosed based on Task Force criteria. Conversely, 1 patient with a normal MRI met Task Force criteria for the diagnosis of ARVC. Based on RV angiograms, 7 patients had findings suggestive of ARVC. The 10 patients without AVRD (based on RVA) also did not meet the necessary criteria for diagnosis of ARVC using Task Force standards. RVA was 100% specific and 100% sensitive compared to MRI that was only 86% sensitive and 60% specific. MRI proved to be most reliable when the images demonstrated gross, lipomatous infiltration, evidenced by a large area of hyperintensity. When the results of MRI and RVA were congruent, the diagnosis was always accurate. CONCLUSION: RVA is more sensitive and specific to diagnose ARVC diagnosis than MRI, at least until MRI protocols are better developed. MRI results are most robust when indicators of ARVC are grossly apparent. False-positive diagnosis by MRI was primarily related to perceived motion abnormalities that were not seen by RVA. One of its greatest potential assets (fat detection) did not enhance diagnostic specificity.     

Arrhythmogenic right ventricular cardiomyopathy in two pairs of monozygotic twins

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inheritant disease with an autosomal dominant mode of transmission with incomplete penetrance and variable expression. Linkage analysis in affected families succeeds in identifying 9 loci determining 9 subtypes of the disease. Genotype phenotype correlation is unclear and the influence of various environmental factors is discussed. OBJECTIVES: Genotype phenotype correlation in 2 pairs of monozygotic twins with ARVC and the role of environmental factors are analyzed. PATIENTS AND METHODS: Among 40 pts with ARVC and their 195 relatives there were 2 pairs of monozygotic twins: brothers, age 47 y; and sisters, age 48 y. History, ECG, Holter monitoring, 2D and Doppler Echo, and MRI were analyzed. RESULTS: Twin brothers: ARVC was diagnosed in the proband after the episode of VT with LBBB morphology (enlarged right ventricle, focal hypokinesia of apex, MR evidence of adipose tissue in RV wall). Identical morphology of RV was seen in asymptomatic twin brother. The patient presenting arrhythmia has been rowing for 4 years. Twin sisters: diagnosis was done during family screening. Both were asymptomatic. RV morphology typical for ARVC was found discrete in one of them (bulges adipose tissue in the RV apex); the latter showed changes suggesting RV abnormality (mild segmental dilatation of infundibulum, adipose tissue in a free wall of the RV). No differences in previous viral infections and sports involvement were observed. CONCLUSIONS: 1. Clinical picture of ARVC in monozygotic twins is not identical. 2. Strenuous effort may be a factor triggering the arrhythmia in pts with ARVC.     

Diagnostic Differentiation Between Arrhythmogenic Cardiomyopathy and Athlete’s Heart by Using Imaging

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an important cause of sudden cardiac death (SCD) in youth and athletes. In the last decade, several studies focused on right ventricular (RV) remodeling in athletes and revealed that features of the physiological adaptation of the right heart to training, such as RV dilation, may overlap with those of ARVC. Therefore, a careful multiparametric evaluation is required for differential diagnosis in order to avoid false diagnosis of ARVC or, in contrast, fail to identify the risk of causing SCD. This review summarizes physiological adaptation of the RV to exercise and describes features that could help distinguishing between athlete’s heart and ARVC.     

The electrocardiogram in right ventricular cardiomyopathy/dysplasia. How can the electrocardiogram assist in understanding the pathologic and functional changes of the heart in this disease?

The electrocardiogram (ECG) provides important information to aid in the diagnosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). The ECG changes may be explained by the pathophysiology of the disease. The proximity of the right ventricle (RV) to the anterior chest leads (V₁ to V₄) explains why the characteristic ECG abnormalities are most prominent in those lends. The specific ECG abnormalities reflect the pathophysiology of the disease including T-wave inversion due to scarring of the free wall of the RV, prolonged S-wave duration due to slow depolarization of the terminal part of the QRS because the RV is the last part of the heart to undergo depolatization, and epsilon waves due to slow conduction in the RV. The extent of ECG abnormalities correlate with the degree of structural change in the RV.     

Carvedilol therapy improved left ventricular function in a patient with arrhythmogenic right ventricular cardiomyopathy

An asymptomatic 35 year-old man was referred to our hospital because of abnormal ECG findings. The ECG showed complete right bundle branch block and left anterior hemiblock. Echocardiography revealed a moderately enlarged right ventricle (RV) and an apical aneurysm. RV wall motion showed diffusely moderate impairment, while the systolic function of the left ventricle (LV) was slightly decreased. The ejection fractions (EF) of the RV and LV were calculated as 28.1% and 41.9% by Simpson's method using multiple cardiac computed tomography (CT) scans. A 24 hour ambulatory ECG showed only 372 single premature ventricular contractions (PVC). Cardiac catheterizaion revealed that the RV was enlarged with prominent trabeculation and decreased motion. In an electrophysiologic study, neither electrical stimulation of the RV nor electrical stimulation plus isoproterenol infusion could induce ventricular tachycardia. Pathological examination of a biopsy from the interventricular septum of the RV revealed fibrofatty change in the myocardium. Based on these results, we made a diagnosis of arrhythmogenic right ventriclular cardiomyopathy (ARVC) and administered 5 mg of carvedilol. Sixty days after the initiation of carvedilol therapy, we performed repeat cardiac CT. The EF of the LV was markedly improved from 41.9% to 62.0%, although the EF of the RV was not changed. The number of PVCs showed no change. This case suggests that carvedilol is not only useful for controlling arrhythmia but also for improving left ventriclular function in some patients with ARVC. Sympathetic overactivity is reported to cause sudden death, so carvedilol may be a first-line drug for some patients with ARVC.