Magnetic resonance imaging findings in patients meeting task force criteria for arrhythmogenic right ventricular dysplasia

INTRODUCTION: Magnet resonance imaging (MRI) findings in patients meeting Task Force criteria for the diagnosis of arrhythmogenic right ventricular dysplasia (ARVD) have not been systematically described. We report qualitative and quantitative MRI findings in ARVD using state-of-the-art MRI. METHODS AND RESULTS: MRI was performed on 12 patients with ARVD who were prospectively diagnosed using the Task Force criteria. The imaging protocol included breath-hold double inversion recovery spin-echo and gradient-echo images. Ventricular volumes and dimensions were compared to 10 age- and sex-matched normal volunteers. High intramyocardial T1 signal similar to fat signal was observed in 9 (75%) of the 12 patients and in none of the controls. Right ventricular (RV) hypertrophy was seen in 5 (42%) patients, trabecular disarray in 7 (59%), and wall thinning in 3 (25%). Both the RV end-diastolic diameter and the outflow tract area were significantly higher in ARVD patients compared to controls (51.2 vs 43.2 mm, P < 0.01; and 14.5 vs 9.3 cm2, P < 0.01, respectively). ARVD patients had a higher RV end-diastolic volume index and lower RV ejection fraction compared with controls (127.4 vs 87.5, P < 0.01; and 41.6% vs 57%, P < 0.01, respectively). CONCLUSION: High intramyocardial T1 signal indicative of fat is seen in a high percentage (75%) of patients who meet the Task Force criteria for ARVD. Trabecular disarray is seen more frequently than wall thinning and aneurysms. RV dimensions and volumes differ significantly in ARVD compared to controls, indicating a role for quantitative evaluation in the diagnosis of ARVD.     

Evolving role of multidetector computed tomography in evaluation of arrhythmogenic right ventricular dysplasia/cardiomyopathy

The purpose of this study was to report 1 center's experience with multidetector computed tomography (MDCT) in the evaluation of patients suspected to have arrhythmogenic right ventricular (RV) dysplasia/cardiomyopathy (ARVD/C). RV dilatation/dysfunction is 1 of the most important criteria for establishing the diagnosis of ARVD/C. Cardiac magnetic resonance imaging (MRI) is the most preferred imaging modality for the diagnosis of ARVD/C. However, many patients with suspected ARVD/C have implantable cardioverter-defibrillators, prohibiting the use of MRI. Thirty-one patients (19 men; mean age 41 +/- 12 years) referred for evaluation of known or suspected ARVD/C had a complete reevaluation including contrast-enhanced cardiac MDCT at the center. Two patients underwent both cardiac MRI and MDCT. Seventeen of 31 patients met Task Force criteria for ARVD/C and were confirmed to have ARVD/C. Multidetector computed tomographic images were analyzed for qualitative and quantitative characteristic findings of ARVD/C. Increased RV trabeculation (p <0.001), RV intramyocardial fat (p <0.001), and scalloping (p <0.001) were significantly associated with the final diagnosis of ARVD/C. RV volumes, RV inlet dimensions, and RV outflow tract surface area were increased in patients with ARVD/C compared with patients who did not meet the criteria. RV and left ventricular functional analysis was performed in 2 patients. In conclusion, cardiac MDCT has a strong potential to detect many qualitative and quantitative abnormalities of the right ventricle in patients with ARVD/C. Limitations include implantable cardioverter-defibrillators and motion artifacts, along with well-known radiation and contrast-induced reaction.     

Noninvasive detection of myocardial fibrosis in arrhythmogenic right ventricular cardiomyopathy using delayed-enhancement magnetic resonance imaging

OBJECTIVES: We evaluated the role of myocardial delayed-enhancement (MDE) magnetic resonance imaging (MRI) for noninvasive detection of fibrosis in Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). BACKGROUND: Arrhythmogenic right ventricular dysplasia/cardiomyopathy is characterized by fibro-fatty replacement of the right ventricle (RV) leading to arrhythmias and RV failure. Endomyocardial biopsy can demonstrate fibro-fatty replacement of the RV myocardium; however, the test is invasive and carries a risk of perforation. METHODS: Thirty consecutive patients were prospectively evaluated for ARVD/C. Magnetic resonance imaging was performed on a 1.5-T scanner. Ten minutes after intravenous administration of 0.2 mmol/kg of gadodiamide, MDE-MRI was obtained. Diagnosis of ARVD/C was based upon the Task Force criteria and did not include MRI findings. RESULTS: Twelve (40%) of 30 patients met the Task Force criteria for ARVD/C. Eight (67%) of the 12 ARVD/C patients demonstrated increased signal on MDE-MRI in the RV compared with none (0%) of the 18 patients without ARVD/C (p <0.001). Endomyocardial biopsy was performed in 9 of the 12 ARVD/C patients. Of the nine patients, four had fibro-fatty changes consistent with the diagnosis of ARVD/C. Each of these patients had increased RV signal on MDE-MRI. None of the patients without ARVD/C had any abnormalities either on histopathology or on MDE-MRI. Electrophysiologic testing revealed inducible sustained ventricular tachycardia (VT) in six of the eight ARVD/C patients with delayed enhancement, compared with none of the ARVD/C patients without delayed enhancement (p=0.01). CONCLUSIONS: Noninvasive detection of RV myocardial fibro-fatty changes in ARVD/C is possible by MDE-MRI. Magnetic resonance imaging findings had an excellent correlation with histopathology and predicted inducible VT on programmed electrical stimulation, suggesting a possible role in evaluation and diagnosis of patients with suspected ARVD/C.     

Magnetic resonance imaging of arrhythmogenic right ventricular dysplasia: sensitivity, specificity, and observer variability of fat detection versus functional analysis of the right ventricle.

OBJECTIVES: The purpose of this study was to determine interobserver agreement for interpretation of magnetic resonance imaging (MRI) examinations of arrhythmogenic right ventricular dysplasia (ARVD) and to determine sensitivity and specificity of fat detection versus functional parameters measured by MRI. BACKGROUND: The interobserver variability of MRI and the relative importance of different MRI parameters (fat detection, regional and global right ventricular [RV] function) for ARVD diagnosis is unknown. METHODS: Two experienced observers blinded to the clinical history independently analyzed MRI datasets obtained from 40 patients evaluated for ARVD. Twenty normal subjects underwent MRI and served as control subjects. The MRI scans were performed according to a standard protocol on a 1.5-T scanner. The observers reported on fat infiltration, global and regional RV function, myocardial thinning, and chamber dilatation qualitatively. The RV volumes were measured on the cine sequences. RESULTS: Interobserver kappa scores for fat infiltration, global and regional RV function, wall thinning, and RV outflow dilatation were 0.74, 0.94, 0.89, 0.93, and 0.93, respectively. Correlation coefficients between observers for RV end-diastolic volume, end-systolic volume, and ejection fraction were 0.93, 0.94, and 0.95, respectively (p < 0.001). Fifteen patients were diagnosed with ARVD using Task Force criteria. Sensitivity of fat infiltration, RV enlargement, and regional RV dysfunction for diagnosing ARVD was 84%, 68%, and 78%, and specificity was 79%, 96%, and 94%, respectively. CONCLUSIONS: Qualitative assessment of RV structure and function is highly reproducible for experienced observers. Among the qualitative parameters, fat infiltration is less reproducible and lacks specificity compared with RV kinetic abnormalities.     

Arrhythmogenic right ventricular dysplasia/ cardiomyopathy

Optional statement Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is a genetic cardiomyopathy characterized by ventricular arrhythmias and structural abnormalities of the right ventricle (RV). The most important aspect in the treatment of ARVD/C is establishing a correct diagnosis based on the International Task Force criteria. In our experience, cardiologists are not aware of these diagnostic criteria for ARVD/C and place too much importance on the results of magnetic resonance imaging of the RV. Patients with ARVD/C generally all have an abnormal 12-lead electrocardiogram, abnormal echocardiogram, and ventricular arrhythmias with a left bundle branch block morphology. If noninvasive testing suggests ARVD, invasive testing with an RV angiogram, RV biopsy, and electrophysiology study are recommended. We encourage patients to participate in the National Institutes of Health-sponsored multicenter clinical trial of ARVD/C (http://www.ARVD.com or http://www.ARVD.org). Once a diagnosis of ARVD/C is established, the main treatment decision involves whether to implant an implantable cardioverter-defibrillator (ICD). ICDs are recommended for patients who have experienced syncope, sudden death, or a sustained ventricular arrhythmia, and also for patients with overt evidence of ARVD, particularly if the electrophysiology study is abnormal or there is a family history of sudden death. We also recommend treatment of patients with ARVD/C with β blockers and angiotensin-converting enzyme inhibitors, and that all patients with ARVD/C be screened for a mutation in the gene for plakophilin-2, because this is present in more than one third of patients with ARVD/C and may be helpful in the management of firstdegree relatives.     

Prospective Study of Cardiac Sarcoid Mimicking Arrhythmogenic Right Ventricular Dysplasia

Introduction: Case studies indicate that cardiac sarcoid may mimic the clinical presentation of arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C); however, the incidence and clinical predictors to diagnose cardiac sarcoid in patients who meet International Task Force criteria for ARVD/C are unknown.
Methods and Results: Patients referred for evaluation of left bundle branch block (LBBB)-type ventricular arrhythmia and suspected ARVD/C were prospectively evaluated by a standardized protocol including right ventricle (RV) cineangiography-guided myocardial biopsy. Sixteen patients had definite ARVD/C and four had probable ARVD/C. Three patients were found to have noncaseating granulomas on biopsy consistent with sarcoid. Age, systemic symptoms, findings on chest X-ray or magnetic resonance imaging (MRI), type of ventricular arrhythmia, RV function, ECG abnormalities, and the presence or duration of late potentials did not discriminate between sarcoid and ARVD/C. Left ventricular dysfunction (ejection fraction <50%) was present in 3/3 patients with cardiac sarcoid, but only 2/17 remaining patients with definite or probable ARVD/C (P = 0.01).
Conclusions: In this prospective study of consecutive patients with suspected ARVD/C evaluated by a standard protocol including biopsy, the incidence of cardiac sarcoid was surprisingly high (15%). Clinical features, with the exception of left ventricular dysfunction and histological findings, did not discriminate between the two entities.     

致心律失常性右室发育不良或心肌病15例的临床特点及疗效

目的 探讨致心律失常性右室发育不良或心肌病(ARVD/C)的临床特点及分析疗效。方法 分析2000～2007年诊断为ARVD/C 15例入院病例资料,对其临床特点作统计分析,并探讨治疗方法及疗效。结果 在ARVD/C 15例病例中(7男),年龄为13～61(31±12)岁,首发症状年龄为10～51(28±11)岁;3例有家族史;6例(40%)有晕厥发作史;5例(33%)患者仅有心悸症状;1例常规心电图检查中发现Epsilon波,见于右侧胸导联V2～3,伴有T波倒置;13例(87%)超声心动图结果异常,主要为RV扩大;4例行心脏磁共振（MRI）检查:见右室壁脂肪信号2例,右室壁变薄3例,右心室扩大3例;有症状的室性心律失常患者接受胺碘酮、β阻滞剂或采用其他抗心律失常药物治疗,但47%的患者(7/15)应用抗心律失常药物治疗无效,3例患者接受射频消融治疗,其中有1例患者出现室性心动过速复发。4例患者植入植入式心脏自动复律除颤器 (ICD),其中1例因多次自动除颤,电池耗竭,而更换ICD。结论 ARVD/C以室性心律失常为主要表现,诊断依靠家族史、晕厥发作史、ECG、超声心动图、MRI。抗心律失常药物的疗效较差,射频消融或植入ICD可治疗致命性心律失常,减少猝死的发生。     

Serial reevaluation for ARVD/C is indicated in patients presenting with left bundle branch block ventricular tachycardia and minor ECG abnormalities

Introduction: Diagnosis of arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is based on a set of criteria proposed by the International Task Force (TF) for Cardiomyopathies in 1994. To fulfill these criteria, presence of both electrocardiographic and anatomical abnormalities must be assessed with ECG and imaging techniques, respectively. This may be difficult in patients with early/mild forms of the disease as detectable structural abnormalities may still be absent. We evaluated in which patients presenting with right ventricular tachycardia (VT) serial reevaluation for ARVD/C is indicated.
Methods and Results: Sixty consecutive patients (41 men, mean age 40±15 years) were evaluated by the TF criteria for possible ARVD/C because of presentation with a left bundle branch block (LBBB) VT, representing 1 minor criterion. The presence on the ECG of a T-wave inversion beyond lead V2 (1 minor), right precordial QRS prolongation (1 major), or an epsilon wave (1 major) was assessed together with the visualization of severe regional/global right ventricle dysfunction (1 major) or mild segmental dilatation/regional hypokinesia (1 minor) by standard imaging techniques. Initially, 22 (37%) patients were diagnosed as having ARVD/C. After 47±39 (range 6–146) months, 23 initially TF-negative patients were reevaluated because of recurrent symptoms, with 12 (52%) additional patients now meeting the TF criteria. Eleven of these 12 (92%) patients presented initially with ECG abnormalities only, but developed structural abnormalities on imaging at follow-up.
Conclusion: ECG abnormalities may precede structural abnormalities warranting serial reevaluation for ARVD/C in initially TF-negative patients presenting with LBBB VT with only ECG abnormalities.     

The S-wave angle identifies arrhythmogenic right ventricular cardiomyopathy in patients with electrocardiographically concealed disease phenotype

Background

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) carries risk of sudden death. We hypothesize that the S-wave angle differentiates ARVD/C with otherwise normal electrocardiograms from controls.

Arrhythmogenic right ventricular cardiomyopathy: a 'final common pathway' that defines clinical phenotype.

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C)is a primary heart muscle disease with distinct characteristics.ARVD/C predominantly affects the right ventricle (RV), withRV dilation and thinning due to fibrofatty infiltration of theventricular myocardium, and ultimately depressed systolic functionleading to right heart failure or biventricular failure.¹ Earlyin its clinical course, ARVD/C typically presents with ventriculararrhythmias (usually with a left bundle branch pattern), syncope,or sudden cardiac death.² Tragically, this clinical scenariocommonly occurs in young, healthy, athletic individuals. A setof clinical criteria, known as the ‘Task Force Criteria’,first described by McKenna et al.³ in 1994 and later modifiedfor inclusion of family members,⁴ utilizes     

Clinico-radiological profile of arrhythmogenic right ventricular dysplasia at a tertiary care center: Two year experience

BackgroundArrythmogenic right ventricular dysplasia (ARVD/C) refers to fibro fatty infiltration replacement of ventricular myocardium especially that of right ventricle. The clinical presentation varies from asymptomatic state to ventricular tachycardia, heart failure and even sudden death. Diagnosis is established using modified ARVD/C taskforce criteria. Among all the various modalities of diagnosis, magnetic resonance imaging (MRI) gives most comprehensive evaluation of both morphological and functional abnormalities in this disease. MRI may not only obviate need for myocardial biopsy but also give insights into the nature of disease like presence of left ventricular myocardial involvement. We present our 2 years experience of ARVD/C patents who were admitted in our center and in whom diagnosis of ARVD/C was supported by excellent MR imaging.Materials and methodsThis study was conducted by Department of Radiology and Cardiology SKIMS, a tertiary care center for a period of 2 years. Patients with suspected ARVD/C based on clinical, electrophysiological and echocardiographic findings were subjected to MR imaging. Patients were excluded if they had history metallic implants, claustrophobia or were uncooperative. In this study stress was laid on diagnostic role of MRI in ARVD/C.ResultsThe median age at presentation was 31 years (range 21–43 years). 80% of patients were males. Most common clinical presentation was palpatations (40%). Syncope was present in 27% and heart failure in 13%. EKG suggestive of ARVD was seen in 87%. Echocardiographic features suggestive of ARVD/C was seen in all 15 patients. Family history of premature sudden death less than 35 years old was present in one patient only. MRI evidence classical for ARVD/C was seen in 80%.ConclusionDemographic features and mode of presentation of our patients is consistent with what has been rest of the world. We performed MRI in all patients to increase the specificity of our diagnosis. MR imaging allows a three-dimensional evaluation of the right ventricle and provides the most important anatomic, functional, and morphologic criteria for diagnosis of ARVD/C within one single study. MR imaging appears to be the optimal imaging technique for detection and follow-up of clinically suspected ARVD/C.     

Yield of Serial Evaluation in At-Risk Family Members of Patients With ARVD/C

Background

Incomplete penetrance and variable expressivity of arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) complicate family screening.

Objectives

The objective of the present study was to determine the optimal approach to longitudinal follow-up regarding: 1) screening interval; and 2) testing strategy in at-risk relatives of ARVD/C patients.

Methods

We included 117 relatives (45% male, age 33.3 ± 16.3 years) from 64 families who were at risk of developing ARVD/C by virtue of their familial predisposition (72% mutation carriers [92% plakophilin-2]; 28% first-degree relatives of a mutation-negative proband). Subjects were evaluated by electrocardiography (ECG), Holter monitoring, signal-averaged ECG, and cardiac magnetic resonance (CMR). Disease progression was defined as the development of a new criterion by the 2010 Task Force Criteria (not the “Hamid criteria”) at last follow-up that was absent at enrollment.

Results

At first evaluation, 43 subjects (37%) fulfilled an ARVD/C diagnosis according to the 2010 Task Force Criteria. Among the remaining 74 subjects (63%), 11 of 37 (30%) with complete re-evaluation experienced disease progression during 4.1 ± 2.3 years of follow-up. Electrical progression (n = 10 [27%], including by ECG [14%], Holter monitoring [11%], or signal-averaged ECG [14%]) was more frequently observed than structural progression (n = 1 [3%] on CMR). All 5 patients (14%) with clinical ARVD/C diagnosis at last follow-up had an abnormal ECG or Holter monitor recording, and the only patient with an abnormal CMR already had an abnormal ECG at enrollment.

Conclusions

Over a mean follow-up of 4 years, our study showed that: 1) almost one-third of at-risk relatives have electrical progression; 2) structural progression is rare; and 3) electrical abnormalities precede detectable structural changes. This information could be valuable in determining family screening protocols.     

Symptomatic arrhythmogenic right ventricular dysplasia/cardiomyopathy. A two-centre retrospective study of 15 symptomatic ARVD/C cases and focus on the diagnostic value of MRI in symptomatic ARVD/C patients

BACKGROUND: Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is associated with sudden death in the young and heart failure in the elderly. The purpose is to review 15 symptomatic ARVD/C cases and also to describe the use of MRI as a diagnostic tool. METHODS AND RESULTS: This retrospective analysis includes 15 patients who presented with symptomatic ARVD/C. Diagnosis was made upon the criteria proposed by the European Society of Cardiology. In all patients there was at least 1 or more abnormal MRI sign. The most frequent abnormalities were focal right ventricular dyskinesia (64%), MRI fatty infiltration (57%) and right ventricular aneurysm or right ventricular outflow tract microaneurysms (57%). Presenting symptoms were palpitations (60%), atypical chest pain (46%), syncope (40%), and aborted sudden death (26%). T-inversion in V2-V3 was seen in 60% of the patients. Thirteen patients (86%) received an ICD implantation. The mean follow-up per patient was 89 months, which resulted in a total follow-up of 111 patient years. Forty-six percent of the patients with an ICD had one or more appropriate shocks during follow-up. To this date no mortality was reported. CONCLUSION: This retrospective study demonstrates that symptomatic ARVD/C patients typically present with symptoms of syncope, palpitations in association with ventricular tachycardia and in a quarter of the cases with aborted sudden cardiac death. The electrocardiogram mostly shows T inversion in the anterior leads. All patients were treated with medication and ICD-implantation or VT-ablation. The malignant nature of the disease in symptomatic ARVD/C patients is stressed by the fact that the presenting symptom is aborted sudden death in a quarter of the cases and the fact that nearly half of the patients with an ICD had at least one appropriate shock during follow-up. There was an abnormal MRI in 100% of the investigated patients. In 20% (3 patients), the MRI criterion (right ventricular dilatation/bulging/aneurysm) was necessary to meet the ESC criteria. Therefore it has become an important tool in our diagnostic work-up when ARVD/C is suspected. We also suggest a change in the diagnostic criteria of ARVD/C. Whereas fatty infiltration seen on RV biopsy is a major criterion, MRI fatty infiltration is not regarded as a diagnostic criterion by the task force to this day.     

Clinical profile of arrhythmogenic right ventricular cardiomyopathy in Chinese patients.

OBJECTIVE: To study the clinical profile of Chinese patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). PATIENTS: Chinese patients who fulfilled the diagnostic criteria of ARVC proposed by the Task Force of the European Society of Cardiology and of the scientific council on cardiomyopathy of the International Society and Federation of Cardiology were recruited for analysis. METHODS: Clinical data of patients with ARVC including age, sex, family history, presenting symptoms, electrocardiograph (ECG), echocardiography, cardiac catheterization, magnetic resonance imaging (MRI), electrophysiology study (EPS) and therapeutic intervention were analyzed. RESULTS: Eleven patients (seven males) were diagnosed with ARVC. Mean age at clinical presentation was 42.6+/-14.8 years. Two patients (18.1%) had positive family history of ARVC or premature sudden cardiac death. The commonest presenting symptoms were palpitation (73%) and dizziness (46%). Spontaneous ventricular tachycardia (VT) was the presenting arrhythmia in 54% and 1 (9%) with ventricular fibrillation and cardiac arrest. Seven patients (64%) had the ECG abnormality as defined by the Task Force. Echocardiography showed right ventricular (RV) dilatation in five patients (46%) and all patients had normal left ventricular function. Nine patients (90%) had RV wall thinning or fibrofatty replacement on MRI examination. Inducible monomorphic VT was detected in four out of nine patients at EPS. All eight patients had normal coronary arteries and left ventriculogram but RV dilatation and global hypokinesia was seen in three patients. Implantable cardioverter defibrillators were implanted in five patients and two of them had shocks delivered during the follow-up period. CONCLUSION: In this study, familial incidence of premature sudden death in patients with ARVC appears to be low and left ventricular involvement in affected individuals is uncommon. MRI is still the best investigation for ARVC.     

The Presence of Epsilon Waves in All Precordial Leads (V1–V6) in a 13‐Year‐Old Boy with Arrhythmogenic Right Ventricular Dysplasia (ARVD)

Electrocardiographic feature is included in the diagnostic criteria for arrthythmogenic right ventricular dysplasia (ARVD) based on the Revised Task Force criteria 2010. The epsilon wave, which reflects delayed conduction of the right ventricle, is considered to be one of the major diagnostic criteria. We reported a 13‐year‐old Thai boy with ARVD who presented with ventricular tachycardia. The presence of epsilon wave in all precordial leads (V₁–V₆) was observed in standard 12‐lead EKG. Extensive scarring of the right and left ventricle was seen on cardiac MRI. The extensive Epsilon wave found in this patient may reflect the extensive ventricular wall involvemen.     

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 dysplasia/cardiomyopathy: Screening, diagnosis, and treatment

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is a heart muscle disorder characterized pathologically by fatty or fibrofatty replacement and electrical instability of the right ventricular myocardium. Clinical manifestations include structural and functional malformations (fatty infiltration, dilatation, aneurysms) of the right ventricle, ECG abnormalities, and presentation with ventricular tachycardias with left bundle branch block pattern or sudden death. The disease often is familial with an autosomal inheritance. The typical hallmarks of ARVD/C are distributed in the so-called "triangle of dysplasia." The functional and morphologic characteristics are relevant to clinical imaging approaches such as contrast angiography, echocardiography, radionuclide angiography, ultrafast computed tomography, and cardiovascular magnetic resonance imaging. Evident forms of the disease are straightforward to diagnose based on a series of diagnostic criteria proposed by the International Task Force for Cardiomyopathy. However, the diagnosis of early and mild forms of the disease often is difficult. Treatment is directed toward preventing life-threatening ventricular arrhythmias in which radiofrequency ablation and implantable defibrillators play an increasing role. Despite new diagnostic and therapeutic approaches in ARVD/C, uncertainties about the etiology of the disease, the genetic basis, the appropriate diagnosis and therapy, and the clinical course of patients with ARVD/C have resulted in several registries to increase our knowledge of this intriguing disease.     

Predictors of appropriate implantable defibrillator therapies in patients with arrhythmogenic right ventricular dysplasia

BACKGROUND: Arrhythmogenic right ventricular dysplasia (ARVD) is an inherited cardiomyopathy characterized by ventricular arrhythmias and sudden cardiac death. The risk factors for sudden death and indications for implantable cardioverter-defibrillator (ICD) placement in patients with ARVD are not well defined. OBJECTIVES: The purpose of this study was to determine which clinical and electrophysiologic variables best predict appropriate ICD therapies in patients with ARVD. Particular attention focused on whether the ICD was implanted for primary or second prevention. METHODS: We enrolled 67 patients (mean age 36 +/- 14 years) with definite or probable ARVD who had undergone ICD placement. Appropriate ICD therapies were recorded, and Kaplan-Meier analysis was used to compare the event-free survival time between patients based upon the indication for ICD placement (primary vs secondary prevention), results of electrophysiologic testing, and whether the patient had probable or definite ARVD. RESULTS: Over a mean follow-up of 4.4 +/- 2.9 years, 40 (73%) of 55 patients who met task force criteria for ARVD and 4 (33%) of 12 patients with probable ARVD had appropriate ICD therapies for ventricular tachycardia/ventricular fibrillation (VT/VF; P = .027). Mean time to ICD therapy was 1.1 +/- 1.4 years. Eleven of 28 patients who received an ICD for primary prevention (39%) and 33 of 35 patients who received an ICD for secondary prevention (85%) experienced appropriate ICD therapies (P = .001). Electrophysiologic testing did not predict appropriate ICD interventions in patients who received an ICD for primary prevention. Fourteen patients (21%) received ICD therapy for life-threatening (VT/VF >240 bpm) arrhythmias. There was no difference in the incidence of life-threatening arrhythmias in the primary and secondary prevention groups (P = .29). CONCLUSION: Patients who meet task force criteria for ARVD are at high risk for sudden cardiac death and should undergo ICD placement for primary and secondary prevention, regardless of electrophysiologic testing results. Further research is needed to confirm that a low-risk subset of patients who may not require ICD placement can be identified.     

Magnetic resonance imaging findings in suspected arrhythmogenic right ventricular dysplasia.

INTRODUCTION: Cardiac magnetic resonance imaging (CMRI) has been used to evaluate right ventricular morphology in suspected arrhythmogenic right ventricular cardiomyopathy (ARVC). We report qualitative CMRI findings in patients with suspected ARVD. METHODS: A retrospective review of images in 35 patients referred for CMRI with clinically suspected ARVD. RESULTS: Eleven patients were considered to have alterations on CMRI. In 5 patients a dilated outflow tract and/or right ventricle was identified; a high intramyocardial T1 fat signal was identified in one patient, regional dyskinesia in two patients, and small excavated pouches in 4 patients. Prominent right ventricular trabeculae were present in 4 patients. CONCLUSIONS: CMRI alterations used for diagnosis of ARVC were identified in approximately one-third of patients referred to our center with either clinical suspicion or diagnosis of ARVC.