MRI assessment of right ventricular dysplasia

Right ventricular dysplasia is a new entity of unknown origin in the classification of cardiomyopathies. Also known as arrhythmogenic right ventricular cardiomyopathy (ARVC) or arrhythmogenic right ventricular dysplasia, it is a disease of the heart muscle characterised by fibroadipose atrophy mainly involving the right ventricle and responsible for severe ventricular arrhythmias and sudden death also in young people. Magnetic resonance imaging provides evidence of ventricular dilatation at the outflow tract, thinning and thickening of the wall, diastolic bulging areas (especially located at the level of the right ventricle outflow tract) and fatty substitution of the myocardium mainly at the level of the right ventricle. Many radiologists erroneously consider the previously described fatty substitution as the main sign of ARVC, even though an evaluation of fat substitution alone may be a source of error for two reasons: firstly, because isolated areas of fatty replacement are not synonymous with ARVC since small non-transmural focal fatty areas of fat are also present in the normal patients; and secondly, because the MRI detection of fat may be overestimated due to partial-volume artefacts with normal subepicardial fat. Cardiac MRI can also be employed for the diagnosis of idiopathic right ventricular outflow tract tachycardia. Considering the evolutive nature of the disease, the non-invasiveness of MRI allows the follow-up of these patients and may be considered an excellent screening modality for the diagnosis of ARVC in family members. Finally, MRI can be employed in electrophysiological studies to locate the arrhythmogenic focus and reduce sampling errors. Electronic Publication     

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.     

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.     

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.     

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.     

Microvascular dysfunction in nonfailing arrhythmogenic right ventricular cardiomyopathy

Purpose  

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a nonischaemic cardiomyopathy and leading cause of sudden death in the young. It has been shown that microvascular dysfunction reflected by an impaired myocardial blood flow (MBF) response to stress is present in patients with other forms of nonischaemic cardiomyopathy, e.g. dilated cardiomyopathy, and that the reduced MBF may be related to a poor prognosis. Therefore, we quantified MBF, coronary flow reserve and coronary vascular resistance in patients with nonfailing ARVC using H₂¹⁵O and PET.     

A case of sudden unexpected infant death involving a homozygotic twin with the thermolabile CPT2 variant,accompanied by rotavirus infection and treatment with an antibiotic containing pivalic acid

We investigated a case of sudden unexpected death involving a 22-month-old male homozygotic twin infant. After both of the twins had suffered from gastroenteritis, one was found dead in his bed, but his brother survived and has since been healthy. Notably, only the deceased had been treated with an antibiotic containing pivalic acid, which may sometimes cause hypocarnitinemia. Postmortem computed tomography and medicolegal autopsy demonstrated severe liver steatosis, and subsequent genetic analysis revealed that the twin had the thermolabile variant of carnitine palmitoyl transferase 2 (CPT2). On the basis of these facts, we concluded that the cause of death had been fatty acid oxidation deficiency accelerated by an antibiotic containing pivalic acid and virus infection in this infant harboring the thermolabile genetic variant of CPT2. Although each factor alone was not fatal, their combination appeared to have resulted in sudden unexpected infant death.     

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.     

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.     

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     

Imaging of programmed cell death in arrhythmogenic right ventricle cardiomyopathy/dysplasia

Background  

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a myocardial disease that predominantly affects the right ventricle (RV). Its hallmark feature is fibrofatty replacement of the RV myocardium. Apoptosis in ARVC/D has been proposed as an important process that mediates the slow, ongoing loss of heart muscle cells which is followed by ventricular dysfunction. We aimed to establish whether cardiac apoptosis can be assessed noninvasively in patients with ARVC/D.     

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.     

Arrhythmogenic right ventricular dysplasia: a possible cause of sudden incapacitation

Arrhythmogenic right ventricular dysplasia (ARVD) is an important cause of sudden death in the young. The classic presentation is with sustained ventricular tachycardia, with an electrocardiographic pattern of a left bundle branch block, but a proportion of the patients may present as sudden cardiac death. Establishing the diagnosis in aviators may be particularly important since it may prevent sudden incapacitation. We present a case of an aviator with ARVD, in whom the diagnosis was delayed despite an abnormal ECG pattern witnessed over 20 yr. The aviator presented with symptomatic sustained ventricular tachycardia at the age of 46 after nearly 3 decades of active flight duty as a rotary wing pilot in the Israeli air force. This case illustrates the potential of ARVD to result in in-flight incapacitation and emphasizes the need to establish the diagnosis early, particularly in aviators.     

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.     

Left side right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy or dysplasia, a heart muscle disease of unknown cause, is anatomically characterized by variable replacement of myocardial muscle with adipose or fibroadipose tissue. It is usually considered a selective disorder whereas concomitant left ventricular involvement has been noted in a few cases. Two cases of the disease with evidence of extensive left ventricular involvement at pathologic examination are described. Hearts from two patients who died suddenly showed extensive biventricular infiltration by fibrofatty tissue in the first case and exclusively in the wall of the left ventricle the localization of the fatty and fibrotic lesions. These findings might suggest that the various localizations of the fibroadipose tissue are rather different expressions of the same disease and it is preferable to be termed 'arrhythmogenic cardiomyopathy' as other studies also indicate.     

Diagnosis of arrhythmogenic right ventricular dysplasia: a review.

Arrhythmogenic right ventricular dysplasia (ARVD) is a myocardial disorder of primarily the right ventricle, with unknown cause and prevalence and with a frequent familial occurrence. The typical clinical manifestation consists of ventricular arrhythmias with a left bundle branch block (LBBB) pattern that occur predominantly in young adults. ARVD may result in sudden death. Other manifestations are electrocardiographic repolarization and depolarization changes, structural abnormalities that range from subtle wall aneurysms within the so-called "triangle of dysplasia" to biventricular regional or global dysfunction, and localized or widespread fibrofatty infiltration of the right ventricular myocardium. The diagnosis of ARVD is based on the presence of major and minor criteria encompassing genetic, electrocardiographic, pathophysiologic, and histopathologic factors. The imaging modalities used to evaluate right ventricular abnormalities include conventional angiography, echocardiography, radionuclide angiography, ultrafast computed tomography, and magnetic resonance (MR) imaging. Among these techniques, MR imaging allows the clearest visualization of the heart. Because MR imaging depicts both functional and structural abnormalities, positive MR imaging findings should be used as important additional criteria in the clinical diagnosis of ARVD. MR imaging appears to be the optimal technique for detection and follow-up of clinically suspected ARVD.     

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。     

Magnetic resonance and computed tomography imaging of arrhythmogenic right ventricular dysplasia

Arrhythmogenic right ventricular dysplasia (ARVD) is a familial cardiomyopathy that causes fibro-fatty replacement of the right ventricle (RV), leading to sudden death due to ventricular arrhythmias. The disease is an important cause of sudden death in individuals younger than 35 years of age. Structural and functional abnormalities of the RV constitute an important diagnostic criterion for the disease. Diagnosis of ARVD is often a challenge as conventional imaging modalities have significant limitations to visualize the RV. Recently, magnetic resonance imaging (MRI) and computed tomographic (CT) imaging have emerged as robust clinical tools for evaluation of myocardial pathology. In addition to providing morphologic and functional information, both imaging modalities have the ability to demonstrate intramyocardial fat, which is the pathological hallmark in ARVD. This article discusses the current status and role of MRI and CT imaging in the diagnosis of ARVD.     

Sudden death due to rupture of the right internal carotid artery in neurofibromatosis type 1: A case report

Vascular involvement is a well-recognized manifestation of neurofibromatosis type 1 (NF1) which has the potential to be fatal when disrupted. We here present a case of sudden death due to the fatal arterial rupture resulted from infiltration of the neurofibromas. A 42-year-old man who suffered from NF1 presented a 1-h history of sudden onset of pain in his right cervical region. His condition worsened and became unconscious on his way to the emergency room. Despite resuscitation efforts, he died 30 min later without regaining consciousness. Autopsy examination showed that a neurofibroma located around the right internal carotid artery, confirmed immunohistochemically with S-100, vimentin and CD34. Furthermore, proliferation of spindle cells positive for S-100 was seen in the wall of right internal carotid artery, which was disrupted and resulted in a hemorrhage. These findings suggest that the artery was disrupted by neurofibromas in the vascular wall, which led to fragility of the vessel. On the basis of these findings, we concluded that the cause of death was asphyxia resulting from airway obstruction compressed by the hematoma due to the arterial rupture. As the locality of the neurofibroma and hemorrhage were closed to the carotid baroreflex, we considered another possible mechanism of his sudden death, which could be cardiac inhibition induced by vagal stimulation. We hope this case will increase recognition of NF-1 vasculopathy when encountering any sudden death in NF1 patients.     

Sixty-four-multislice computed tomography in a patient with arrhythmogenic right ventricular dysplasia

Arrhythmogenic right ventricular dysplasia (ARVD) is an inheritable cardiomyopathy that is characterized by fibrofatty infiltration of the RV myocardium, often resulting in arrhythmias and sudden cardiac death. The diagnosis often requires imaging of the right ventricle, typically by magnetic resonance imaging. We describe a case of AVRD in which cardiac computed tomography was used as the imaging method for the right ventricle. The CT images showed changes consistent with ARVD to include RV enlargement, excessive trabeculations, fatty infiltration, and marked RV hypokinesia. We believe these images show a novel use for multislice CT in the diagnostic evaluation of patients with suspected ARVD.