Helical CT features of arrhythmogenic right ventricular cardiomyopathy.

Arrhythmogenic right ventricular cardiomyopathy (ARVC), also known as arrhythmogenic right ventricular dysplasia, is a disorder of the heart muscle of unknown origin. It is characterized by electrical instability of the heart as a result of replacement of the right ventricular myocardium with fatty or fibrous fatty tissue. Dilatation of the right ventricle; fatty tissue in conspicuous trabeculae of the right ventricle, especially in the anterior wall, apex, and inferior (diaphragmatic) wall; and a scalloped appearance (bulging) of the right ventricular wall are characteristic findings at helical computed tomography (CT) that may be used to diagnose ARVC. Fatty tissue in the left ventricle and ventricular septum is seen relatively frequently in ARVC, and fat in the ventricular septum is another useful finding for diagnosis of ARVC with helical CT. ARVC is usually diagnosed on the basis of clinical or pathologic findings, and electron-beam CT is superior to nongated helical CT in assessment of abnormal right ventricular function. However, with knowledge of the characteristic findings, standard nongated helical CT can be helpful in diagnosing ARVC.     

Marked lipomatous infiltration of the right ventricle: MRI findings in relation to arrhythmogenic right ventricular dysplasia

OBJECTIVE: The purpose of this study was to describe the structure and function of the heart in the presence of marked lipomatous infiltration of the right ventricular wall in 13 patients referred for second opinions about fatty infiltration of the right ventricular wall and suspected arrhythmogenic right ventricular dysplasia. CONCLUSION: Lipomatous infiltration with right ventricular thickness > or = 6 mm on MRI but without regional or global functional abnormalities of the right ventricle appears to be distinct from fatty right ventricle associated with arrhythmogenic right ventricular dysplasia. The finding of right ventricular fat must be interpreted cautiously to avoid the pharmacologic and defibrillator intervention associated with management of arrhythmogenic right ventricular dysplasia.     

Arrhythmogenic right ventricular dysplasia: MR features

Arrhythmogenic right ventricular dysplasia (ARVD) is a heart disease characterized by a total or partial fat replacement of the myocardium. A total of 30 patients were studied with a suspected diagnosis of ARVD. Clinical criteria used for evaluation of ARVD were: (a) ventricular origin arrhythmias with a left bundle branch block configuration, (b) T-wave inversion in the anterior precordial leads, (c) ventricular kinetic alterations observed using echocardiography and angiography and (d) cardiac failure when there are no pathologies attributable to other heart diseases. All patients had serial EKG and echocardiography tests. One third of patients underwent angiocardiography; 7 of 30 had Holter; 7 of 30 had exercise test just to evaluate the effectiveness of the anti-arrhythmic therapy. All patients underwent MRI examination. The following MRI criteria were used: (a) high-intensity areas indicating the fatty substitution of the myocardium, (b) ectasia of the right ventricular outflow tract, (c) dyskinetic bulges, (d) dilation of the right ventricle and (e) enlargement of the right atrium. The diagnosis of ARVD was classified as highly probable for patients manifesting at least three positive criteria, probable with two positive criteria, dubious with one and negative in the absence of all criteria. Highly probable diagnosis of ARVD was made in 8 patients, probable in 4, dubious in 7 and negative in 11. The MRI technique is very effective in the assessment of ARVD. The MRI criteria may be helpful in the diagnosis of this condition. Received 9 August 1995; Revision received 27 December 1995; Accepted 16 July 1996     

Sudden death during exercise in a juvenile with arrhythmogenic right ventricular cardiomyopathy and desmoglein-2 gene substitution: a case report

One type of arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited disorder resulting in fatty replacement of the right ventricular wall and consequent fatal arrhythmias. It is a major cause of sudden death in young people. Mutations in the genes encoding desmosomal proteins have been identified as a cause of ARVC. We report a case of sudden death during exercise in a juvenile. This case showed fatty replacement of the right ventricular wall, which suggests that ARVC may have been associated with the cause of death. Further genetic analysis showed a novel homozygous R292C substitution of the desmoglein-2 gene (DSG2), which encodes a desmosomal protein. In addition to morphological examination, genetic analysis may be useful for diagnosis of ARVC-suspected autopsy cases.     

Differentiation of RVOT-VT and ARVC in an elite athlete

BACKGROUND: Differentiation of right ventricular outflow tract-ventricular tachycardia (RVOT-VT) and arrhythmogenic right ventricular cardiomyopathy (ARVC) can be problematic in athletes. The high incidence of sudden death as the first clinical manifestation in ARVC highlights the importance of correct diagnosis and treatment. We report on the case of RVOT-VT in an elite female sprinter, and we review the literature on ventricular tachycardia (VT) in the absence of structural heart disease and ARVC. DISCUSSION: Of patients who present with VT, 10% have no obvious structural disease. In the case of idiopathic VT from the RVOT and LVOT, the arrhythmia is monomorphic and generally not familial. In both disorders, the resting ECG has no identifiable abnormalities, and the echocardiogram and coronary angiography are usually normal. ARVC is a heart muscle disorder characterized by structural and functional abnormalities of the right ventricle due to a fibro-fatty replacement of the myocardium. The natural history of ARVC is considered to include four distinct phases. The early concealed phase of ARVC demonstrates ECG abnormalities concomitant to right and left ventricular dyskinesias. Differential diagnosis during this phase is problematic due to the presence of left bundle branch block morphology VT together with ECG anomalies commonly observed in athletes in RVOT-VT. Furthermore, long-standing VT in RVOT-VT may result in ventricular wall motion abnormalities mimicking ARVC. Radiofrequency ablation may be a valuable tool in the differential diagnosis, because this technique is highly effective in the treatment of RVOT-VT and of limited value in ARVC. Continued follow-up evaluation is an important for the confirmation of disease status after the diagnosis of idiopathic RVOT-VT.     

Computed tomography demonstration of lipomatous metaplasia of the left ventricle following myocardial infarction

Replacement of myocardium by fat, particularly of the right ventricle, is often diagnosed as arrhythmogenic right ventricular dysplasia. At autopsy, however, 68% of scars associated with chronic ischemic heart disease have shown fatty metaplasia in the scar. Four patients with a past history of previous myocardial infarctions and computed tomography demonstration of fatty change in left ventricular regions of hypokinesis and infarction are presented. It is proposed that these findings represent ischemic fatty metaplasia, an alternative etiology of fatty tissue replacing myocardium.     

Utility of ECG-gated MDCT to differentiate patients with ARVC/D from patients with ventricular tachyarrhythmias

BackgroundThe accuracy of electrocardiogram-gated CT for diagnosing arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is uncertain.ObjectiveWe propose a comprehensive system for scoring characteristic CT findings to diagnose ARVC/D and discuss its utility.MethodsSeventy-seven patients (mean age, 43.1 years; 48 male) diagnosed with ARVC/D or with suspected ARVC/D on the basis of ventricular tachyarrhythmias underwent CT with and without contrast enhancement. We retrospectively graded characteristic CT findings (fatty tissue, bulging appearance, and dilatation of the right ventricle) as minor (1 point) or major (2 points) and then validated our scoring system’s utility for diagnosing ARVC/D with the use of the modified 2010 Task Force criteria as the reference standard.ResultsWe diagnosed 27 of 77 patients with ARVC/D (23 definite, 4 borderline), observing each CT finding more often in patients with ARVC/D than in patients without ARVC/D: fatty tissue, 74.1% versus 12.0%; bulging appearance, 74.1% versus 34.0%; and RV dilatation, 92.6% versus 44.0%. However, observation of each finding in both groups could cause false positive diagnosis. Recursive partitioning analysis showed the superiority of our CT scoring system over methods that used each CT finding and CT findings without fatty tissue for distinguishing ARVC/D and non-ARVC/D. For overall (definite and borderline) and definite ARVC/D diagnosis, sensitivities were 77.8% and 87.0%, specificities were 96.0% and 94.4%, positive predictive values were 91.3% and 87.0%, negative predictive values were 88.9% and 94.4%, and accuracies were 89.6% and 92.2%, respectively.ConclusionsOur CT scoring system showed excellent diagnostic ability and might aid differentiation of ARVC/D from ventricular tachyarrhythmias.     

致心律不齐性右室心肌病的MRI诊断

目的：用心脏MR新技术评价致心律不齐性右室心肌病（ARVC）的MRI征象，探讨MR扫描技术。方法：对15例临床、超声诊断或疑为ARVC的病人进行RM检查，使用GE Signa1.5TCV/iMR扫描系统，扫描序列包括黑血技术：双反转恢复快速自旋回波(double-IR FSE)和三反转自旋回波（triple-IR FSE）序列；白血技术：快速电影成像（fastcine）序列。扫描平面有短轴面、四腔面和长轴面。结果：10例诊断为ARVC，ARVC的主要MRI表现有：右室壁脂肪信号3例，右室壁变薄9例，右心室扩大6例，室壁瘤形成2例，右心腔内慢血流信号9例，右室射血分数降低6例，右房扩大3例。右室乳状肌和左室心尖部、室间隔前部累及2例。黑血技术可显示心脏解剖、形态及组织特性，白血技术主要了解心脏功能及心肌壁的运动，短轴面和四腔面显示病变较满意。结论：ARVC的RMI表现具有一定的特征，多序列、多平面成像的MR新技术对该病的诊断更准确、更可靠。     

MRI of the cardiomyopathies

We examined the potentialities of Magnetic resonance imaging (MRI) in the evaluation of the main cardiomyopathies: hypertrophic, dilated, restrictive and arrhythmogenic right ventricular. The hypertrophic cardiomyopathy is generally adequately investigated by echocardiography, that well defines the myocardial thickening and the obstruction of the left ventricular output. However, by echocardiography we still have difficulties in the evaluation of the apex of the left ventricle and the right ventricle involvement. MRI provides a complete evaluation of the heart with a clear evidence also of the echocardiographic dark zones by means of a clear evidence of the apex of the right ventricle. The dilated form is also well investigated by MRI that provides a clear evaluation of the volumes, mass and ejection fraction by means of the 3D analysis including conditions of the ventricular remodelling. Moreover, this technique helps in the differential diagnosis of acute myocarditis. In the acute phase of myocarditis (first 2 weeks), in fact, the myocardium produces high signal intensity on the T2 weighted sequences due to the presence of oedema. The third form of cardiomyopathy is the restrictive one, characterised by reduced diastolic filling and diastolic volume, normality of the systolic function and parietal thickness, interstitial fibrosis and enlargement of both atria. The mean potentiality of MRI is related to the differential diagnosis with constrictive pericarditis. Only in the former, the pericardium appears irregularly thickened with areas exceeding 4 mm of pericardial thickness. Finally, the right ventricular arrhythmogenic cardiomyopathy represents the main indication to MRI evaluation. With this imaging modality we are can obtain a clear morpho-functional evaluation of the right ventricle and distinguish the intramyocardial adipose substitution characterised by areas of high signal in the myocardium.     

Right ventricular fat infiltration in asymptomatic subjects: observations from ECG-gated 16-slice multidetector CT

OBJECTIVE: To analyze the computed tomography (CT) findings of fatty replacement in the right ventricle (RV) of asymptomatic subjects and to correlate the CT findings with electrocardiogram (ECG) abnormalities. METHODS: This prospective study included 996 subjects who underwent ECG-gated 16-slice CT for determination of coronary calcium scores. The CT findings were analyzed in terms of location, pattern, and degree of RV fat infiltration, along with the shape and dimension of RV. The RV fat was regarded present when a region showed less than or equal to -30 Hounsfield units as revealed by CT. RESULTS: Computed tomography features suggestive of RV fat were found in 169 subjects (17%; 136 men and 33 women; mean age, 56.3 years). The most frequent location of fat was the basal superior wall (93%); next was the middle superior wall (72%); and then, the RV outflow tract (44%). Subjects with moderate to severe involvement were older than those with mild involvement (P = 0.012). In 3 subjects, the RV wall thickening with fat was more than 5 mm. Angular deformity and undulating appearance of the RV also occurred in 25 (15%) and 20 subjects (12%), respectively. However, these were not patients with ECG findings positive for arrhythmogenic RV dysplasia. CONCLUSIONS: Asymptomatic subjects may have fat in RV on CT. However, these subjects show no RV dysfunction or significant ECG-abnormalities consistent with the diagnosis of arrhythmogenic RV dysplasia.     

MRT bei arrhythmogener rechtsventrikulärer Dysplasie/Kardiomyopathie (ARVD/C)

Arrhythmogenic right ventricular dysplasia/cardiomyopathy is a congenital disease that may present with sudden cardiac death as the first manifestation. Standards for the difficult clinical diagnosis are the so-called modified Task Force criteria that incorporate imaging-based, electrocardiographic and anamnestic information. Cardiac magnetic resonance imaging (MRI) is the standard technique for imaging of the right ventricle and can compliment the recent ARVD/C diagnosis criteria by providing exact information on right ventricular size and function. It is the most reliable modality available for the detection of right ventricular aneurysms and the quantification of ventricular size. Furthermore, MRI is able to identify areas of fatty or fibrous replacement within the right ventricular myocardium in a non-invasive way. However, a suspicion of ARVD/C cannot be confirmed or excluded based on MRI findings alone. In clinical routine cardiac MRI is an enormously important component in the ARVD/C diagnostic toolbox; however, MRI can only act as one part of the diagnostic puzzle and should exclusively be performed by experienced centers using specifically tailored protocols.     

Assessment of right ventricular lipomatosis by histomorphometry in control adult autopsy cases

A histomorphometry study was carried out to assess the degree of right ventricular lipomatosis in control autopsy cases and to evaluate if this was correlated with parameters such as sex, age, body mass index (BMI) and heart weight. A total of 70 adult cases were selected from cases of violent death between 1991 and 1999 and where autopsies were carried out in the Department of Pathology and Forensic Medicine in Garches. All cases with heart pathology, abnormal BMI or putrefaction were excluded. Cases with lung or liver pathology were also excluded. Furthermore, 10 adult autopsy cases who died suddenly of arrhythmogenic right ventricular cardiomyopathy (ARVC) were compared with 10 age and sex-matched control cases. Details on sex, age, BMI and heart weight were obtained from the post-mortem records. For each case one sample of the right front ventricular wall was fixed in 10% neutral saline-buffered formalin and one 5-μm-section was stained with haematoxylin and eosin. The Leica Quantimet 500 analysis system was used for the histomorphometrical study. The mean degree of lipomatosis was measured under blind conditions in the ventricular wall and epicardial fat was excluded. Covariance analysis and the Wilcoxon test were used for statistics. The mean age of the control population was 37.5 years, the sex ratio was 1.9:1 (male:female). The mean degree of lipomatosis was 17.03% and the degree of lipomatosis was significantly correlated with age (p = 0.0029) but not with sex, BMI and heart weight. There was a statistically significant increase in fat in ARVC cases compared with age and sex-matched controls (p < 0.001). Fat infiltration of the right ventricle could be an adipose involution due to an ageing process and heavy fat infiltration can be difficult to distinguish from ARVC. Our study suggests that fat infiltration is not essential for the post-mortem diagnosis of ARVC which also requires fibrosis and degenerating myocytes trapped within areas of fibrosis. Received: 6 October 2000 / Accepted: 20 March 2001     

Arrhythmogenic dysplasia of the right ventricle. Evaluation of 7 cases using computerized tomography

Right ventricular arrhythmogenic dysplasia is a rare cardiomyopathy which involves the right ventricle either totally or partially. Up to now diagnoses have been based on Ecg, hemodynamics, angiography and echocardiography. This paper deals with the first 7 patients examined also by means of Computed Tomography. The CT picture is well defined and rather accurate. The most important elements are: total (6/7) or partial (1/7) enlargement of the right ventricle; thinning of right ventricular myocardium (6/7); marked increase in subepicardial fat limited to the right ventricular wall (7/7); right ventricle hypokinesia (7/7). A good correlation exists between CT, echographic and traditional methodologies findings. Because of its densitometric evaluation, CT is much more precise in the demonstration of fatty degeneration. Moreover, it can be very useful in differentiating intracardiac thrombi from hypertrophic papillary muscles and trabeculae.     

Left-sided ventricular cardiomyopathy with minimal right ventricular involvement

Left-sided ventricular arrhythmogenic cardiomyopathy is rare and represents a rather different expression of the arrhythmogenic right ventricular (RV) cardiomyopathy (ARVC). Among sudden cardiac deaths, ARVC plays a significant role. ARVC is considered as a cardiomyopathy of unknown aetiology that primarily involves the right ventricle (RV) and is characterized by progressive replacement of myocytes by fibro-fatty tissue, complicating a spectrum of arrhythmias. Predominant ARVC with left ventricular (LV) involvement is also reported. The LV variant of arrhythmogenic cardiomyopathy with minimal or no RV involvement is rare. A 31-year-old previously healthy young man, without a significant family history, was found dead in bed. Autopsy revealed an enlarged heart and asymmetrical LV hypertrophy with widely patent coronary arteries. LV myocardium demonstrated evidence of prominent epicardial fibro-fatty tissue that is predominantly fatty in nature and infiltrates into the myocardium. Microscopy of the LV free wall showed fibro-fatty tissue infiltration into the epicardial aspect of the LV that extends well into the mid-myocardium. A moderate to marked degree of interstitial fibrous tissue deposition was noted about adipocytes and cardiomyocytes. There was no evidence of chronic ischaemic changes or of significant myofibre disarray. The RV showed minimal fibro-fatty infiltration with normal myocytes. This report highlights a rare case which confirms previous observations that the LV variant of arrhythmogenic cardiomyopathy could occur with minimal or no involvement of the RV. Further studies are required in this context to elicit the spectrum and the exact nature of this disease.     

Arrhythmogenic left ventricular dysplasia' and sudden death

A 32-year-old man who died suddenly and unexpectedly was found at autopsy to have prominent fatty infiltration of his left ventricle with fibrous scarring, in the presence of normal coronary arteries. The right ventricle was minimally involved. A diagnosis of ventricular dysplasia largely limited to the left ventricle was made. Subsequent family screening identified a brother with clinical manifestations of ventricular dysplasia. This case provides further evidence for the association of left ventricular dysplasia with sudden death, and demonstrates that left ventricular involvement may also be inheritable. Whether predominantly left ventricular dysplasia is a manifestation of right ventricular dysplasia, or is a separate entity, is yet to be determined.     

Sudden cardiac death due to arrhythmogenic right ventricular cardiomyopathy and cystic tumor of the AV node

An 18-year-old white male collapsed suddenly in his home and died. At autopsy, the right ventricle of the decedent was noted to be dilated with marked thinning of the wall focally. Microscopically, the myocardium of the right ventricle was noted to be significantly thinned focally, where transmural infiltration with fibroadipose tissue was noted. Depending on the criteria utilized to render such a diagnosis, these findings were consistent with arrhythmogenic right ventricular cardiomyopathy (ARVC). Subsequent microscopic examination of the SA and AV node, however, revealed the presence of a cystic tumor of the AV node (CTAVN), a known cause of sudden death from arrhythmia. The case represents the first reported case of ARVC and CTAVN occurring together in the same individual.     

MR evaluation of arrhythmogenic right ventricular cardiomyopathy in pediatric patients

OBJECTIVE: The aim of our study was to correlate the findings of three MR imaging sequences with the clinical findings of possible arrhythmogenic right ventricular cardiomyopathy in pediatric patients. MATERIALS AND METHODS: Twenty-six consecutive pediatric patients underwent MR imaging with ECG-gated non-breath-hold spin-echo T1-weighted non-fat-suppressed and fat-suppressed sequences. The MR images were evaluated for thinning or fat signal in the right ventricular wall and for enlargement or increased trabeculation of the right ventricle or right ventricular outflow tract. Cine MR imaging was used to assess wall motion abnormalities. Cardiac biopsy was performed in 17 patients. Biopsy results and other clinical findings suggesting arrhythmogenic right ventricular cardiomyopathy were tabulated. RESULTS: Two MR imaging studies were of poor quality as a result of arrhythmias, and one study was incomplete. In the 23 remaining patients, there were (mean +/- SD) 1.5 +/- 1.0 and 0.8 +/- 1.0 findings of possible arrhythmogenic right ventricular cardiomyopathy in the non-fat-suppressed and the fat-suppressed sequences, respectively. Fat-compatible signal in the myocardium was detected in 16 (70%) of 23 non-fat-suppressed studies and in five (22%) of 23 fat-suppressed studies (p = 0.003). The non-fat-suppressed sequence had a higher sensitivity (75% vs 43%) and a lower specificity (38% vs 75%) for fatty infiltration than did the fat-suppressed sequence when correlated with the biopsies. The linear correlation between all MR findings and all clinical diagnostic criteria, including biopsy, was better for the combination of cine and both T1 sequences (r = 0.58) than for the non-fat-suppressed (r = 0.53) or fat-suppressed (r = 0.46) T1 sequences alone. CONCLUSION: MR imaging showed moderate correlation with the clinical criteria in the diagnosis of arrhythmogenic right ventricular cardiomyopathy.     

Assessment of inflammation in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia

Purpose  

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a myocardial disease that predominantly affects the right ventricle (RV). Its hallmark feature is fibro-fatty replacement of RV myocardium. However, patchy inflammatory infiltrates in the RV are also consistently reported using autopsy and myocardial biopsy. Although the role of inflammation in ARVC/D is unresolved, the ability to assess inflammation non-invasively may aid in the diagnostic process. We aimed to establish whether cardiac inflammation can be assessed non-invasively in ARVC/D patients.     

Diagnostic work up of arrhythmogenic right ventricular cardiomyopathy by cardiovascular magnetic resonance (CMR). Consensus statement

Cardiovascular Magnetic Resonance (CMR) has become a widespread diagnostic tool. Since its introduction CMR has been used to image patients with known or suspected arrhythmogenic right ventricular cardiomyopathy (ARVC). Several abnormalities have been found and described by CMR and at present this diagnostic tool is considered very important for the diagnosis. However, the diagnosis of ARVC relies upon the fulfillment of both clinical and functional criteria and CMR can provide several but not all the information useful for the diagnosis. Furthermore, some findings such as evidence of right ventricular epicardial fat once considered a peculiar marker of ARVC, have been shown to possess a low specificity. This document was prepared by representatives of the three Italian official Organizations involved in CMR. Its main scope is to highlight the problems encountered when studying patients with suspected ARVC by CMR, to indicate the basic technical equipment needed, to recommend a proper imaging protocol and to offer a consensus on the main diagnostic features relevant for the diagnosis.     

Arrhythmogenic right ventricular cardiomyopathy/dysplasia mimicking rape homicide: a case report

Arrhythmogenic right ventricular cardiomyopathy (ARVC), also known as arrhythmogenic right ventricular dysplasia, is a known cause of sudden unexplained death in young, otherwise healthy adults. In the forensic setting, several cases of fatal ARVC have been reported, mostly occurring during physical exercise. However, a very few cases present where the death scene is mistaken for a homicide. We report here the case of a 23-year-old woman, found dead, lying in the snow on an isolated property. The woman's genitals were exposed, with her trousers down over her thighs. Rape homicide was strongly suspected, but autopsy findings proved otherwise.