Endomyocardial biopsy in arrhythmogenic right ventricular cardiomyopathy

Endomyocardial Biopsy: The Forgotten Piece in the Arrhythmogenic Cardiomyopathy Puzzle

Background Endomyocardial biopsy (EMB) is part of 2010 Task Force Criteria (TFC) for arrhythmogenic right ventricular cardiomyopathy (ARVC). However, its usage has been curtailed because of its low presumed diagnostic yield, and it is now a poorly used tool. This study aims to analyze the contribution of EMB to the final diagnosis of ARVC. Methods and Results We included 104 consecutive patients evaluated for a suspicion of ARVC, who were referred for EMB. Patients with suspected left dominant pattern were excluded from the primary analysis. Subjects were initially stratified according to TFC without considering EMB. After EMB, patients were reclassified accordingly, and the reclassification rate was calculated. EMB yielded a diagnostic finding in 92 patients (85.5%). After including EMB evaluation, 20 (43%) more patients "at risk" received a definite diagnosis of ARVC. Overall, 59 patients received a definite diagnosis of ARVC, 34% only after EMB. EMB appeared to be the better-performing exam with respect to the final diagnosis (β, 2.2; area uder the curve, 0.73; P<0.05). The reclassification improvement after EMB measured 28%. TFC score increased from 3.5±1.3 to 4.3±1.4 (P<0.001). Notably, active inflammation was present in 6 (10%) patients. Minor complications were reported in only 2% of the cohort. In patients with suspected left-dominant disease, conventional TFC performed poorly. Conclusions Electroanatomic voltage mapping-guided EMB was safe and yielded an optimal diagnostic yield. It allowed upgrading of the diagnosis of nearly one-third of the patients considered "at risk." Classical TFC without EMB performed poorly in patients with the left dominant form of ARVC.

Arrhythmogenic Left Ventricular Cardiomyopathy: Genotype-Phenotype Correlations and New Diagnostic Criteria

Arrhythmogenic cardiomyopathy (ACM) is an inherited heart muscle disease characterized by loss of ventricular myocardium and fibrofatty replacement, which predisposes to scar-related ventricular arrhythmias and sudden cardiac death, particularly in the young and athletes. Although in its original description the disease was characterized by an exclusive or at least predominant right ventricle (RV) involvement, it has been demonstrated that the fibrofatty scar can also localize in the left ventricle (LV), with the LV lesion that can equalize or even overcome that of the RV. While the right-dominant form is typically associated with mutations in genes encoding for desmosomal proteins, other (non-desmosomal) mutations have been showed to cause the biventricular and left-dominant variants. This has led to a critical evaluation of the 2010 International Task Force criteria, which exclusively addressed the right phenotypic manifestations of ACM. An International Expert consensus document has been recently developed to provide upgraded criteria (“the Padua Criteria”) for the diagnosis of the whole spectrum of ACM phenotypes, particularly left-dominant forms, highlighting the use of cardiac magnetic resonance. This review aims to offer an overview of the current knowledge on the genetic basis, the phenotypic expressions, and the diagnosis of left-sided variants, both biventricular and left-dominant, of ACM.

2019 HRS expert consensus statement on evaluation, risk stratification, and management of arrhythmogenic cardiomyopathy

Arrhythmogenic cardiomyopathy (ACM) is an arrhythmogenic disorder of the myocardium not secondary to ischemic, hypertensive, or valvular heart disease. ACM incorporates a broad spectrum of genetic, systemic, infectious, and inflammatory disorders. This designation includes, but is not limited to, arrhythmogenic right/left ventricular cardiomyopathy, cardiac amyloidosis, sarcoidosis, Chagas disease, and left ventricular noncompaction. The ACM phenotype overlaps with other cardiomyopathies, particularly dilated cardiomyopathy with arrhythmia presentation that may be associated with ventricular dilatation and/or impaired systolic function. This expert consensus statement provides the clinician with guidance on evaluation and management of ACM and includes clinically relevant information on genetics and disease mechanisms. PICO questions were utilized to evaluate contemporary evidence and provide clinical guidance related to exercise in arrhythmogenic right ventricular cardiomyopathy. Recommendations were developed and approved by an expert writing group, after a systematic literature search with evidence tables, and discussion of their own clinical experience, to present the current knowledge in the field. Each recommendation is presented using the Class of Recommendation and Level of Evidence system formulated by the American College of Cardiology and the American Heart Association and is accompanied by references and explanatory text to provide essential context. The ongoing recognition of the genetic basis of ACM provides the opportunity to examine the diverse triggers and potential common pathway for the development of disease and arrhythmia.

Arrhythmogenic Ventricular Cardiomyopathy Associated With Fibromuscular Dysplasia of Ostial Right Main Coronary Artery

In this article, we report the autopsy findings of a 23-year-old woman, who was found unconscious at home by her relatives. During the transportation to the hospital, the woman was handed over to the ambulance personnel, who were the first to provide cardiopulmonary resuscitation. In the hospital, after an hour-lasting asystole, the heart activity was restored. Prolonged cardiac arrest led to hypoxic brain injury, which resulted in a persistent coma. Examinations carried out during hospitalization detected hypokinetic interventricular septum, frequent ventricular extrasystoles and ventricular fibrillation. The patient died within 35 hours of admission to the hospital. Gross findings of the heart included a noticeable increase of the adipose tissue in the right ventricular wall, where histologically focal myocardial atrophy with focal transmural lipomatosis reaching endocardium were detected. Death was attributed to arrhythmogenic ventricular cardiomyopathy. Pathogenic variants in JUP gene and KCNH2 gene confirmed the diagnosis. Other finding of note was fibromuscular dysplasia of ostial right main coronary artery causing a significant luminal narrowing.

Histopathologic features of alcoholic cardiomyopathy compared with idiopathic dilated cardiomyopathy

BACKGROUND

The histologic difference between alcoholic cardiomyopathy (ACM) and idiopathic dilated cardiomyopathy (IDCM) is unclear. The present study aimed to identify the quantitative pathologic features of ACM compared with IDCM.

METHODS

Specimens from 6 regions (anterior left ventricle [LV], lateral LV, inferior LV, interventricular septum [IVS], anterior right ventricle [RV], and inferior RV) were sampled from each explanted heart. Specimens from 4 healthy donor hearts were obtained as normal control. Tissues were sectioned and Masson trichrome stained. Histomorphometry was performed to evaluate the amount of myocyte, fibrosis, fatty tissue, and interstitium by Image-Pro Plus 6.0 (Media Cybernetics).

RESULTS

A total of 408 specimens were obtained from 34 ACMs and 34 IDCMs; 8 specimens were obtained from 4 healthy donor hearts. Compared to healthy donor hearts, we observed an increase in fibrosis which replaces myocytes in myocardium of end-stage cardiomyopathy. The overall myocyte ratio in myocardium was 69.5 ± 8.7% in ACM vs 71.9 ± 7.4% in IDCM (P < .05). The percentage of interstitium was 10.8 ± 4.8% in ACM vs 9.2 ± 6.2% in IDCM (P < .05). A significant difference of fibrosis, fatty tissue was not discovered. Moreover, the myocyte area was 65.37 ± 11.8% in ACM LV vs 70.03 ± 9.0% in IDCM LV (P < .001).

CONCLUSION

We described histologic characteristics in ACM and IDCM. There might be a quantitative difference of myocyte, interstitium in myocardium between ACM and IDCM, especially in LV. No difference was found in the percentage of fibrosis between the 2 groups.

Absence of a primary role for TTN missense variants in arrhythmogenic cardiomyopathy: From a clinical and pathological perspective

BACKGROUND

Arrhythmogenic cardiomyopathy (ACM) is an inheritable heart disease characterized by fibro-fatty replacement of the myocardium. TTN missense variants were previously reported as a pathogenic factor for ACM.

HYPOTHESIS

TTN missense variants are commonly identified in ACM, but have limited effect on the phenotype of ACM.

METHODS

We sequenced 15 ACM-related genes in 35 patients who had a heart transplantation and quantified myocardium, and fibrous and adipose tissue in blocks of the explanted heart. Clinical and pathological characteristics were compared between patients with TTN variants and others. Pedigree analysis was performed in 3 families with TTN variants.

RESULTS

TTN variants were detected in 11 patients (all missense, 9 heterozygous and 2 oligogenic form). The TTN truncating variant was absent in the cohort. Patients with TTN variants had late onset age of the disease (31 ±13 years vs 17 ±3 years, P = 0.049) and age of heart transplantation (41 ±14 years vs 24 ±9 years, P = 0.027), larger left ventricle end-diastolic diameter (62 ±10 mm vs 45 ±10 mm, P = 0.019), smaller right ventricular outflow tract (34 ±14 mm vs 50 ±15 mm, P = 0.046), more myocardium (40.8% ±29.4% vs 13.8% ±11.0%, P = 0.017), and less adipose tissue (43.0% ±30.9% vs 66.9% ±18.5%, P = 0.036) in right ventricle than those with desmosomal variants. There was few difference between patients with TTN variants and those without variants. Pedigrees showed none of the family members with TTN missense variants had a disease phenotype, indicating a very low penetrance.

CONCLUSIONS

TTN missense variants was commonly identified in ACM patients in this cohort, but hardly played a primary role in ACM as causative variants.

Arrhythmogenic Cardiomyopathy: Electrical and Structural Phenotypes

This overview gives an update on the molecular mechanisms, clinical manifestations, diagnosis and therapy of arrhythmogenic cardiomyopathy (ACM). ACM is mostly hereditary and associated with mutations in genes encoding proteins of the intercalated disc. Three subtypes have been proposed: the classical right-dominant subtype generally referred to as ARVC/D, biventricular forms with early biventricular involvement and left-dominant subtypes with predominant LV involvement. Typical symptoms include palpitations, arrhythmic (pre)syncope and sudden cardiac arrest due to ventricular arrhythmias, which typically occur in athletes. At later stages, heart failure may occur. Diagnosis is established with the 2010 Task Force Criteria (TFC). Modern imaging tools are crucial for ACM diagnosis, including both echocardiography and cardiac magnetic resonance imaging for detecting functional and structural alternations. Of note, structural findings often become visible after electrical alterations, such as premature ventricular beats, ventricular fibrillation (VF) and ventricular tachycardia (VT). 12-lead ECG is important to assess for depolarisation and repolarisation abnormalities, including T-wave inversions as the most common ECG abnormality. Family history and the detection of causative mutations, mostly affecting the desmosome, have been incorporated in the TFC, and stress the importance of cascade family screening. Differential diagnoses include idiopathic right ventricular outflow tract (RVOT) VT, sarcoidosis, congenital heart disease, myocarditis, dilated cardiomyopathy, athlete's heart, Brugada syndrome and RV infarction. Therapeutic strategies include restriction from endurance and competitive sports, β-blockers, antiarrhythmic drugs, heart failure medication, implantable cardioverter-defibrillators and endocardial/epicardial catheter ablation.

Pathophysiology and prevention of sudden cardiac death

Sudden cardiac death (SCD) is known to occur in individuals with diverse diseases. Each disease state has a specific etiology and pathophysiology, and is diagnosed and treated differently. Etiologies for SCD include cardiac arrhythmias, coronary artery disease, congenital coronary artery anomalies, hypertrophic cardiomyopathy, arrhythmogenic right ventricular dysplasia, dilated cardiomyopathy, and aortic valve stenosis. A potential unifying mechanism of SCD in these diseases involves a massive stimulation of the sympathetic nervous system’s stress response and the subsequent elevation of circulating catecholamines. The diagnosis of cardiac diseases that contribute to an increased risk for SCD is accomplished by a combination of different techniques including electrocardiography, echocardiography, magnetic resonance imaging, and invasive cardiac catheterization. Several therapies including anti-arrhythmic drugs, β-blockers, and antiplatelet agents may be used as medical treatment in patients for the prevention of SCD. Invasive therapies including percutaneous angioplasty, coronary artery bypass surgery, and implantable cardioverter-defibrillators are also used in the clinical management of SCD.

A case report of lethal post-viral lymphocytic myocarditis with exclusive location in the right ventricle

The inflammatory involvement of vital organs may represent a dangerous and life-threatening situation: in particular, the inflammation of the myocardial tissue of the heart may lead to severe consequences since the clinical history of the disease may be completely asymptomatic, any clinical sign may be lacking, thus preventing correct diagnosis and treatment. This may occur even in the case of myocarditis and may lead to unexpected death whose cause can be assessable only by means of a thorough histopathological examination. The article reports the case of 61-year old female who developed a flu-like syndrome with very few symptoms, followed by sudden death in three weeks. The autopsy and following histopathological investigations identified the cause of death in a post-viral lymphocytic myocarditis, probably related to the previous infectious disease, and alternative causes (as arrhythmic ventricular dysplasia, vasculitis, sarcoidosis and giant cell myocarditis) were excluded. The exclusive location in the right ventricle was a peculiar finding. The case highlights the importance of the myocardium of the right ventricle, a tissue which is often less considered even in histopathological surveys. The exclusive location of myocarditis in the right ventricle is a rare event but in this case fully responsible for death.

Feasibility of combined unipolar and bipolar voltage maps to improve sensitivity of endomyocardial biopsy

BACKGROUND

Endomyocardial biopsy (EMB) has a low sensitivity. Electroanatomic voltage mapping (EVM) is effective in guiding EMB thanks to its ability in identifying and locating low-voltage regions. The analysis of unipolar EVM can correlate with epicardial pathological involvement. We evaluated the unipolar EVM in EMB areas to determine whether it can increase EMB sensitivity in diagnosing epicardial diseases.

METHODS AND RESULTS

We performed endocardial bipolar EVM-guided EMBs in 29 patients and we analyzed unipolar EVM at withdrawal sites. Eighty myocardial samples were collected (mean, 2.8±0.9; median, 3 fragments per patient) and 60 were suitable for histological analysis. Ten specimens (17%) were collected from an area with discordant normal bipolar/low-voltage unipolar EVM and they were diagnostic or suggestive for arrhythmogenic right ventricular dysplasia/cardiomyopathy in 6 patients, for myocarditis and sarcoidosis in 1 patient each. Six samples (10%) were collected from an area with discordant low-voltage bipolar/normal unipolar EVM and they showed nonspecific features. The sensitivity of unipolar EVMs for a diagnostic biopsy finding EMB was significantly higher compared with bipolar EVMs analyzed according to samples (P<0.01) and patients (P=0.008). The specificity of unipolar EMB was better than bipolar EMB when analyzed for all samples (P=0.0014) but the difference did not reach statistical significance when analyzed by patient (P=0.083). The diagnostic yield was 63.3% for the bipolar and 83.3% for the unipolar EVM.

CONCLUSIONS

These findings suggest that use of a combined bipolar/unipolar map may be able to improve the diagnostic yield of endomyocardial ventricular biopsy.

Electrocardiographic (ECG) clues to differentiate idiopathic right ventricular outflow tract tachycardia (RVOTT) from arrhythmogenic right ventricular cardiomyopathy (ARVC)

INTRODUCTION

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a genetic cardiomyopathy that most commonly affects young adults. The most commonly observed reason of death in patients suffering from ARVC/D is sudden cardiac death (SCD). On the other hand, idiopathic right ventricular outflow tract tachycardia (RVOT VT) usually has a benign course. Both of the entities may have ventricular tachycardia (VT) with left bundle branch block (LBBB) pattern and inferior axis. We tried to propose new discriminating electrocardiographic indices for differentiation of foretold entities.

MATERIAL AND METHOD

This was a retrospective study. We reviewed records of patients admitted between 2003 and 2012 with the diagnosis of either ARVC/D or RVOT VT that presented with VT (LBBB morphology).

RESULT

A total of fifty nine patients (30 RVOT VT and 29 ARVC/D) were enrolled. In ARVC/D group, men were dominant while the reverse was true of RVOT VT. Palpitation was more common in the RVOT VT group (90% vs. 66.7%), but aborted SCD and sustained VT were more common in ARVC/D group. The new ECG criteria proposed by us mean QRS duration in V1-V3, QRS difference in right and left precordial leads, S wave upstroke duration, JT interval dispersion, QRS and JT interval of right to left precordial leads were all significantly longer in ARVC/D when compared to RVOT VT patients (p < 0.001).

CONCLUSION

The proposed ECG criteria can be used for non-invasive diagnosis of ARVC/D and incorporation in the future updates of ARVC/D task force criteria.

Clinical interpretation of genetic variants in arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy is an inherited cardiac entity characterized by right ventricular, or biventricular, fibrofatty replacement of myocardium. Structural alterations may lead to sudden cardiac death, mainly in young males during exercise. Autosomal dominant pattern of inheritance is reported in most parts of pathogenic genetic variations identified. Currently, 13 genes have been associated with the disease but nearly 40 % of clinically diagnosed cases remain without a genetic diagnosis. New genetic technologies allow further genetic analysis, generating a significant amount of genetic data in novel genes, which is often classified as of ambiguous significance. We focus on genetic advances of arrhythmogenic right ventricular cardiomyopathy, helping clinicians to interpret and translate genetic data into clinical practice.

Is cardiac MRI an effective test for arrhythmogenic right ventricular cardiomyopathy diagnosis?

AIM: To evaluate the referrals with suspected arrhythmogenic right ventricular cardiomyopathy (ARVC) and compare cardiac MR (cMR) findings against clinical diagnosis.

METHODS: A retrospective analysis of 114 (age range 16 to 83, males 55% and females 45%) patients referred for cMR with a suspected diagnosis of ARVC between May 2006 and February 2010 was performed after obtaining institutional approval for service evaluation. Reasons for referral including clinical symptoms and family history of sudden death, electrocardiogram and echo abnormalities, cMR findings, final clinical diagnosis and information about clinical management were obtained. The results of cMR were classified as major, minor, non-specific or negative depending on both functional and tissue characterisation and the cMR results were compared against the final clinical diagnosis.

RESULTS: The most common reasons for referral included arrhythmias (30%) and a family history of sudden death (20%). Of the total cohort of 114 patients: 4 patients (4%) had major cMR findings for ARVC, 13 patients (11%) had minor cMR findings, 2 patients had non-specific cMR findings relating to the right ventricle and 95 patients had a negative cMR. Of the 4 patients who had major cMR findings, 3 (75%) had a positive clinical diagnosis. In contrast, of the 13 patients who had minor cMR findings, only 2 (15%) had a positive clinical diagnosis. Out of the 95 negative patients, clinical details were available for 81 patients and none of them had ARVC. Excluding the 14 patients with no clinical data and final diagnosis, the sensitivity of the test was 100%, specificity 87%, positive predictive value 29% and the negative predictive value 100%.

CONCLUSION: CMR is a useful tool for ARVC evaluation because of the high negative predictive value as the outcome has a significant impact on the clinical decision-making.

Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC/D): A Systematic Literature Review

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a genetic form of cardiomyopathy (CM) usually transmitted with an autosomal dominant pattern. It primary affects the right ventricle (RV), but may involve the left ventricle (LV) and culminate in biventricular heart failure (HF), life threatening ventricular arrhythmias and sudden cardiac death (SCD). It accounts for 11%-22% of cases of SCD in the young athlete population. Pathologically is characterized by myocardial atrophy, fibrofatty replacement and chamber dilation. Diagnosis is often difficult due to the nonspecific nature of the disease and the broad spectrum of phenotypic variations. Therefore consensus diagnostic criteria have been developed and combined electrocardiography, echocardiography, cardiac magnetic resonance imaging (CMRI) and myocardial biopsy. Early detection, family screening and risk stratification are the cornerstones in the diagnostic evaluation. Implantable cardioverter-defibrillator (ICD) implantation, ablative procedures and heart transplantation are currently the main therapeutic options.

Utility of cardiac magnetic resonance in the evaluation of unselected patients with possible arrhythmogenic right ventricular cardiomyopathy

INTRODUCTION

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a rare but important cause of sudden cardiac death. We investigated the role of cardiac magnetic resonance imaging (CMR) in the evaluation of patients with suspected ARVC referred by a general cardiology service.

METHODS

Ninety-two patients (mean age 48 ± 15, 49% female), referred for CMR assessment of possible ARVC, were reviewed. CMR included both functional and tissue characteristic imaging.

RESULTS

No patients had ARVC based on the 1994 Task Force Criteria (TFC) prior to CMR, but 4 met proposed Modified TFC; 15% met one major (±1 minor) TFC, 71% 1 or 2 minor TFC, and 14% no TFC. Reasons for CMR referral included symptomatic arrhythmia of likely RV origin (28%), Electrocardiogram/Holter abnormalities (28%), echocardiographic features suspicious of ARVC (19%), and family history of ARVC (8%). CMR findings strongly suggestive of ARVC were found in nine patients (10%), although only three were considered typical. Of these patients two met 1 major TFC and seven met 1 or 2 minor TFC. CMR findings included RV thinning, aneurysm, and diastolic out-pouching, but only 1 patient had definite fatty infiltration of the RV. Incidentally, CMR detected important, previously undiagnosed pathology, including anomalous pulmonary venous drainage (2 patients) and non-ischaemic cardiomyopathy (6%). CMR was normal in 63%, with minor abnormalities in 29%.

CONCLUSIONS

CMR may play an important diagnostic role in the evaluation of possible ARVC. Patients who do not meet TFC for diagnosis may have CMR features typical of ARVC. Additionally CMR may detect other hitherto undiagnosed structural or functional abnormalities that alter patient management. However the majority of patients referred have a low pretest probability of ARVC, and the rate of normal CMR scans is high.

New pathological insights into cardiac amyloidosis: implications for non-invasive diagnosis

BACKGROUND

Knowledge of the patterns of myocardial amyloid accumulation could improve the interpretation of electrocardiographic, echocardiographic and magnetic resonance imaging findings of amyloidosis. We assessed the extent and pattern of myocardial amyloid infiltration in explanted or autopsied hearts of patients with cardiomyopathy related to acquired monoclonal immunoglobulin light-chain (AL) or hereditary transthyretin (TTR) related amyloidosis (ATTR).

METHODS

We analyzed nine explanted/autopsied hearts from patients with AL (n = 4) and ATTR (n = 5) cardiac amyloidosis. For each heart, a biventricular histological macrosection was obtained at mid-ventricular level and analyzed with both inspective and computer-assisted histologic and histomorphometric analysis aimed in particular at quantifying muscle cells, fibrosis and amyloid infiltration.

RESULTS

The extent of amyloid infiltration of the left ventricle (LV) ranged from 45 to 76% (median [interquartile range (IQR)] = 57% [51-64]) of the overall surface. Although LV trabecular and subendocardial were the most infiltrated layers (45-94%, median [IQR] = 73% [67-84] and from 44 to 71%, median [IQR] = 57% [49-59], respectively), intra- and inter-patient heterogeneity was high. Three main patterns of amyloid infiltration of the LV were identified: diffuse (five cases), mainly subendocardial (two cases), and mainly segmental (two cases). The extent of amyloid infiltration of the right ventricle ranged from 48 to 93% (median [IQR] = 61% [59-83]); contributions of parietal and trabecular layers ranged from 32 to 99% (median [IQR] = 63% [47-88]) and from 49 to 93% (median [IQR] = 74% [64-79]), respectively.

CONCLUSIONS

In amyloidotic cardiomyopathy, amyloid deposition is highly heterogeneous. Different patterns of infiltration are identifiable, including diffuse, mainly segmental and mainly subendocardial. Awareness of this variability can help the interpretation of ECGs, echocardiograms and magnetic resonance imaging.

Impact of the revision of arrhythmogenic right ventricular cardiomyopathy/dysplasia task force criteria on its prevalence by CMR criteria

OBJECTIVES

The purpose of our study was to assess the impact of revised versus original criteria on the prevalence of arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) criteria in cardiac magnetic resonance (CMR) studies.

BACKGROUND

Recently, the ARVC/D task force criteria have been revised, aiming for a better diagnostic sensitivity. The implications of this revision on clinical decision making are unknown.

METHODS

We retrospectively evaluated the CMR scans of 294 patients referred for ARVC/D between 2005 and 2010, and determined the presence or absence of major and minor CMR criteria using the original and the revised task force criteria. Previously, major and minor abnormalities were identified by the presence of right ventricle dilation (global or segmental), right ventricle microaneurysm, or regional hypokinesis. The revised criteria require the combination of severe regional wall motion abnormalities (akinesis or dyskinesis or dyssynchrony) with global right ventricle dilation or dysfunction (quantitative assessment).

RESULTS

Applying the original criteria, 69 patients (23.5%) had major original criteria, versus 19 patients (6.5%) with the revised criteria. Forty-three patients (62.3%) with major original criteria did not meet any of the revised criteria. Using the original criteria, 172 patients (58.5%) had at least 1 minor criterion versus 12 patients (4%) with the revised task force criteria; 167 patients (97%) with minor original criteria did not meet any of the revised criteria. In the subgroup of 134 patients with complete diagnostic work-up of ARVC, 10 patients met the diagnosis of proven ARVC/D without counting imaging criteria. Only 4 of 10 met major criteria according to the revised CMR criteria; none met minor criteria. However, 112 of 124 patients without ARVC/D were correctly classified as negative by major and minor criteria (specificity 94% and 96%, respectively).

CONCLUSIONS

In our experience, the revision of the ARVC/D task force imaging criteria significantly reduced the overall prevalence of major and minor criteria. The revision, although maintaining a high specificity, may not have improved the sensitivity for identifying patients with ARVC/D. Larger studies including follow-up are required.

Correlation between signal-averaged ECG and the histologic evaluation of the myocardial substrate in right ventricular outflow tract arrhythmias

BACKGROUND

The differential diagnosis between idiopathic and cardiomyopathy-related right ventricular outflow tract (RVOT) ventricular arrhythmias (VAs) is crucial. Signal-averaged ECG (SAECG) abnormalities are frequent in cardiomyopathy-related RVOT-VAs, although their pathophysiologic basis and diagnostic value in this setting are undefined. We tested the association between SAECG and the myocardial substrate underlying RVOT-VAs.

METHODS AND RESULTS

Twenty-four consecutive patients (median age, 50 years [42-59]; 12 men) with RVOT-VAs (10 with frequent [>1000/24 hours] premature ventricular contractions, 14 with ventricular tachycardias) underwent SAECG with 40-Hz filtering and electroanatomic mapping (EAM) with EAM-guided biopsy for characterization of the RVOT-VAs substrate. A filtered averaged QRS (fQRS) was obtained and analyzed for fQRS duration, low amplitude signal duration<40 mV (LAS40), and root-mean-square voltage in the last 40 ms of the QRS (RMS40). Standard definition of EAM scar was used. EAM-guided biopsy diagnosed ARVC in 11 (46%), myocarditis in 8 (33%), and idiopathic RVOT-VAs in 5 (21%) patients. Patients with cardiomyopathy-related RVOT-VAs had ≥1 EAM scar (median, 2 [1-2]; all with RVOT scar). EAM of patients with idiopathic RVOT-VAs was normal. Patients with cardiomyopathy-related RVOT-VAs had significantly longer fQRS (106 ms [92-132] versus 83 ms [82-84], P=0.01) and LAS40 (39 ms [36-51] versus 19 ms [18-21], P=0.02), and lower RMS40 (18 µV [9-26] versus 33 µV [32-33], P=0.04). A significant linear correlation was found between the extension (cm2) of the RVOT scar and all 3 SAECG parameters (rs=0.76, P<0.001 for the fQRSd; rs=0.73, P<0.001 for the LAS40; and rs=-0.72, P<0.001 for the RMS40). Using the established 2 of 3 criteria (ie, late potentials), SAECG diagnosed cardiomyopathy-related RVOT-VAs with high positive (100%) but low negative (38%) predictive values and missed 7 of 9 (78%) patients with RVOT scar<8 cm2.

CONCLUSIONS

In patients with RVOT-VAs, abnormal SAECG parameters reflect the presence of extensive cardiomyopathic involvement of the RVOT. However, a negative SAECG does not reliably rule out cardiomyopathy-related RVOT-VAs in the presence of a small RVOT scar.

Arrhythmogenic right ventricular cardiomyopathy: asymptomatic to life threatening as illustrated by the cases of two sisters

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a heart muscle disorder of unknown cause that is characterised by fibrofatty replacement, primarily of the right ventricular myocardium, which can lead to life-threatening arrhythmias. It is a disease with a very diverse phenotype. In the present article we describe two sisters, each with a different manifestation of this disorder. The first patient died suddenly at the age of 18 during exercise. Her 17-year-old sister did not have any abnormalities at first cardiac consultation, but a few years later she met several diagnostic criteria for ARVC and an internal cardioverter defibrillator was implanted. Genetic analysis identified a mutation in the plakophilin- 2 (PKP2) gene. Cardiac evaluation of a third sister did not reveal any abnormalities and no mutation in the PKP2 gene was found. Thus, ARVC can vary in its clinical presentation, not only between siblings but also in time. This raises difficulties for the physician for diagnosis, treatment and followup. It is important for the physician involved to consider this disease in patients with palpitations and syncope, especially when there is a family history of ARVC or unexplained sudden death. (Neth Heart J 2007;15:348-53.).

Arrhythmogenic forms of heart failure in children

There are various underlying causes of tachycardia-induced cardiomyopathy (TIC), and it is critical that it be considered in any patient who presents with a newly diagnosed dilated cardiomyopathy. Unlike most other forms of cardiomyopathy, TIC should be considered a treatable form of cardiomyopathy and it is imperative that the diagnosis be fully considered. A 12-lead ECG should be obtained in all patients with a dilated cardiomyopathy. Prompt diagnosis and therapy of this relatively uncommon cause of heart failure is critical and has the potential to completely reverse the ventricular dysfunction that may be present in this abnormality.

Noninvasive diagnosis of electroanatomic abnormalities in arrhythmogenic right ventricular cardiomyopathy

BACKGROUND

The diagnostic reliability and pathophysiologic relevance of different noninvasive diagnostic criteria for arrhythmogenic right ventricular cardiomyopathy (ARVC) are undefined. We tested the association between noninvasive diagnostic criteria for ARVC and the presence of low-voltage areas (LVAs) detected at electroanatomic voltage mapping (EAM).

METHODS AND RESULTS

Noninvasive diagnostic criteria, including ECG, signal-averaged ECG (SAECG), and cardiac magnetic resonance (CMR) criteria, were compared with the presence and location of LVAs detected at right ventricular (RV) EAM in 17 patients (9 men) aged 50 ± 16 years with biopsy specimen-proven ARVC. LVAs were found in 15 (88%) patients. Patients with surface ECG abnormalities showed a higher degree of RV involvement than those without ECG abnormalities (number of LVAs, 1.8 ± 0.5 versus 0.9 ± 0.6, respectively; P < 0.01). A significant association was found between SAECG abnormalities and LVAs in the RV outflow tract (P = 0.03) but not between SAECG parameters and LVAs in other RV regions. Among CMR findings, RV delayed enhancement was more significantly associated with the distribution of LVAs (free wall, P < 0.01; outflow tract, P < 0.01; posteroinferior wall, P = 0.02). Regional RV dysfunction also showed a good correlation with LVAs, with the most significant association being found with the free wall (P = 0.01), whereas RV fat infiltration at CMR was not correlated with LVAs.

CONCLUSION

In patients with ARVC, SAECG abnormalities correlate with the presence of LVAs selectively in the RV outflow tract, whereas surface ECG abnormalities are associated with a more diffuse RV involvement. Myocardial delayed enhancement is the CMR finding more strongly associated with LVAs, thus supporting the appropriateness of its inclusion among diagnostic criteria for ARVC.

Endomyocardial biopsy--when and how?

Endomyocardial biopsy is a commonly performed useful procedure utilized for the evaluation of cardiac tissue. Biopsy may be used to monitor transplant rejection, but it has many other applications including the evaluation of myocarditis, cardiomyopathy, chest pain, arrhythmia, and secondary involvement by systemic diseases. Drug toxicity may be evaluated and neoplasms may be biopsied. Recent developments include advances in myocardial and viral molecular biology and advances in image or electrophysiology guided biopsy. The utility of endomyocardial biopsy is reviewed with consideration of these advances.

Arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) originally emerged as a pathologic diagnosis based on distinctive autopsy findings in cases of premature sudden death. Subsequently these characteristic pathologic features were associated with ventricular tachycardia of right ventricular origin and syncope. ARVC is a rare condition and our understanding of the disorder has been confounded by multiple small, highly selected series. Driven by both family studies and improved non-invasive imaging tools the clinical diagnosis of ARVC has broadened, in some instances extending far beyond the original limits of the syndrome. In recent years false-positive diagnoses have increased, thus stimulating investigators to move toward more rigorous clinical criteria. Despite the efforts of a Task Force to establish a baseline for subsequent empiric testing, these criteria have often inadvertently been used as a definitive diagnostic tool in the absence of prospective data. Recent genetic studies have revealed substantial etiologic heterogeneity, and ARVC is emerging as a syndrome consisting of multiple discrete disease entities, in part explaining the tremendous variation in clinical features and natural history seen in prior reports.

Arrhythmogenic cardiomyopathy: etiology, diagnosis, and treatment

Arrhythmogenic right ventricular cardiomyopathy (ARVC) has a prevalence of at least 1 in 1000, is a leading cause of sudden cardiac death in people aged < or =35 years, and accounts for up to 10% of deaths from undiagnosed cardiac disease in the <65 age group. The classic form of the disease has an early predilection for the right ventricle, but recognition of left-dominant and biventricular subtypes has prompted proposal of the broader term arrhythmogenic cardiomyopathy. The clinical profile of the disease bridges the gap between the cardiomyopathies and inherited arrhythmia syndromes. The early "concealed" phase is characterized by propensity toward ventricular tachyarrhythmia in the setting of well-preserved morphology, histology, and ventricular function. As the disease progresses, however, myocyte loss, inflammation, and fibroadiposis become evident. Up to 40% of cases harbor rare variants in genes encoding components of the desmosome, specialized intercellular junctions that confer mechanical strength to cardiac and epithelial tissue, and may also participate in signaling networks. Phenotypic heterogeneity and the nonspecific nature of associated features complicate clinical diagnosis, which requires multipronged cardiovascular investigation rather than a single test. Development of a prospectively validated risk-stratification algorithm for the full disease spectrum remains the foremost clinical challenge.

Ablation of ventricular arrhythmias in arrhythmogenic right ventricular dysplasia

Arrhythmogenic right ventricular dysplasia (ARVD) is a genetically determined myocardial disease characterized by fibrofatty replacement of the right ventricular wall. Ventricular tachyarrhythmias can be seen in the early stages of the disease, which is one of the most important causes of sudden death in young healthy individuals. Radiofrequency (RF) catheter ablation is an option for the treatment of medically refractory ventricular arrhythmias and it has shown to successfully abolish recurrent ventricular tachycardias (VT) as well as reduce the frequency in defibrillator therapies. However, variable acute and long-term success rates have been reported. The current mapping and ablation techniques include activation and entrainment mapping during tolerated VT and substrate ablation using 3-dimensional electroanatomic mapping systems. This article aims at providing a comprehensive review of RF catheter ablation of ventricular arrhythmias in the context of ARVD.

Arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy is a rare inherited heart-muscle disease that is a cause of sudden death in young people and athletes. Causative mutations in genes encoding desmosomal proteins have been identified and the disease is nowadays regarded as a genetically determined myocardial dystrophy. The left ventricle is so frequently involved as to support the adoption of the broad term arrhythmogenic cardiomyopathy. Clinical diagnosis can be achieved by demonstrating function and structure changes of the right ventricle, electrocardiogram depolarisation and repolarisation abnormalities, ventricular arrhythmias, and fibrofatty replacement through endomyocardial biopsy. Although specific, the standardised diagnostic criteria lack sensitivity for early disease and their primary application remains in establishing the diagnosis in probands. However, the main clinical targets are early detection of concealed forms and risk stratification for preventive strategies, which include physical exercise restriction, antiarrhythmic drugs, and implantable cardioverter-defibrillator therapy. Cascade genetic screening of family members of gene-positive probands allows the identification of asymptomatic carriers who would require lifelong follow-up due to the age-related penetrance.

High prevalence of myocarditis mimicking arrhythmogenic right ventricular cardiomyopathy differential diagnosis by electroanatomic mapping-guided endomyocardial biopsy

OBJECTIVES

We evaluated the diagnostic contribution and the therapeutic and prognostic implications of 3-dimensional electroanatomic mapping (EAM)-guided endomyocardial biopsy (EMB) in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC).

BACKGROUND

ARVC is a frequent cause of life-threatening ventricular arrhythmias and sudden death in young people. The value of current diagnostic criteria and the role of imaging techniques and EMB are still debated.

METHODS

We studied 30 consecutive patients (17 male, mean age 43 +/- 17 years) with a noninvasive diagnosis of ARVC according to current criteria. All patients underwent 3-dimensional EAM-guided EMB.

RESULTS

Twenty-nine (97%) of 30 patients presented an abnormal voltage map. Histology and immunohistochemistry confirmed the diagnosis of ARVC in 15 patients, and showed active myocarditis according to Dallas criteria in the remaining 15 patients. Patients with ARVC were not distinguishable on the basis of clinical features, presence, and severity of structural and functional right ventricular abnormalities and 3-dimensional EAM findings. On the basis of clinical and histological features, a cardioverter-defibrillator was implanted in 13 patients with biopsy-proven ARVC and in 1 patient only with myocarditis. At a mean follow-up of 21 +/- 8 months, 7 (47%) patients with ARVC experienced a recurrence of symptomatic sustained ventricular arrhythmias with appropriate defibrillator intervention in all cases. All patients with myocarditis remained asymptomatic and free from arrhythmic events.

CONCLUSIONS

Right ventricular myocarditis frequently mimics ARVC. Three-dimensional EAM-guided EMB is a safe and effective tool in differential diagnosis and in the selection of the most appropriate therapeutic strategy.

Arrhythmogenic right ventricular cardiomyopathy: a survey of the investigations at the University of Padua

The purpose of this paper is to review the history of the clinico-pathologic investigations performed at the University of Padua on an old morbid entity ("parchment heart"), which, in the 1960s, led to the clinical description of the disease, in the 1980s to the revival of the scientific interest, and in the mid 1990s to the understanding of the genetic background. All the steps of the progressive knowledge are reviewed: necropsy of young people who died suddenly, in vivo diagnosis by ECG, echocardiography, angiocardiography, endomyocardial biopsy, nuclear magnetic resonance, and diagnostic criteria. Familial occurrence with autosomic dominant transmission and various penetrance was documented. Gene defects were recently mapped both to chromosome 14q23-q24 and 1q42-q43, thus providing evidence for genetic heterogeneity. The pathologic substrates of arrhythmogenic right ventricular cardiomyopathy pointed to an acquired progressive myocardial atrophy with fibro-fatty replacement of dying myocytes. Nowadays the disease is definitively regarded as a primary myocardial disorder and it has been included in the revised WHO classification of cardiomyopathies.

Targeted endomyocardial biopsy using electroanatomical voltage mapping in the early stage of arrhythmogenic right ventricular cardiomyopathy

Endomyocardial biopsy (EMB) is useful for making a diagnosis of cardiomyopathy. However, the sensitivity of conventional EMB specimens from the interventricular septum is low in arrhythmogenic right ventricular cardiomyopathy (ARVC), especially in the early stage, because of the limited location of the affected tissue. Therefore, it is important to be able to target only the affected tissue in order to improve the sensitivity of the EMB, especially in the early stage of ARVC. A significant correlation between the low voltage areas identified by the electroanatomical voltage mapping (EVM) and abnormal findings from the EMB in ARVC has been reported. We describe an innovative strategy for performing EMB, using EVM to identify the local affected area and to perform a selective EMB from that area.

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.

Quantitative assessment of endomyocardial biopsy in arrhythmogenic right ventricular cardiomyopathy/dysplasia: an in vitro validation of diagnostic criteria

AIMS

To provide a standardized endomyocardial biopsy (EMB) protocol and diagnostic quantitative parameters for arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). The Task Force criteria for the in vivo diagnosis of ARVC/D include tissue characterization by EMB as a major criterion.

METHODS AND RESULTS

EMBs were simulated in vitro with a Cordis bioptome in explanted hearts from six groups: diffuse (n = 10) and segmental (n = 10) ARVC/D, dilated cardiomyopathy (DC) (n = 10), controls (n = 10), adipositas cordis (n = 10), elderly >80 years (n = 10). Sampling sites were the RV inferior-subtricuspid, antero-apical, and mid-outflow tract (RVOT), the septum, and the left ventricle (LV). Histomorphometry was performed to evaluate the amount of myocardium and fibrous and fatty tissues. Myocyte diameters and abnormalities were also assessed. By selecting a 95% specificity, the ARVC/D diagnostic cut-offs on cumulative RV EMB samples are myocardium <59%, fibrosis >31% and fat >22% (80, 50, and 50% sensitivity, respectively). By excluding elderly and obese people groups a lower cut-off for fat was found (>9%). A high variability between different RV sampling sites was observed; the antero-apical was the most informative region although fat at this level is non-specific. No useful diagnostic cut-off for fatty tissue was identified at the antero-apical and RVOT area. No significant difference was found for any tissue parameter either in septal or in LV EMB. Increased RV myocyte diameters and cytological changes were detected in ARVC/D and DC.

CONCLUSION

The residual myocardium is the main diagnostic morphometric parameter in ARVC/D, whereas fat at the apex is non-specific. Sensitivity and specificity vary according to the RV region. Target sampling of the triangle of dysplasia is required, although only a single region is often informative, emphasizing the usefulness of imaging-guided EMB. There is no diagnostic value of either septal or LV EMB. Cardiomyopathic changes of the myocytes also appear important for establishing a pathological diagnosis.

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

Voltage Mapping-Guided Biopsy in ARVC/D.

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.

Three-dimensional electroanatomical voltage mapping and histologic evaluation of myocardial substrate in right ventricular outflow tract tachycardia

OBJECTIVES

We tested whether 3-dimensional electroanatomical voltage mapping (EVM) may help in the differential diagnosis between idiopathic right ventricular outflow tract (RVOT) tachycardia and arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D).

BACKGROUND

Right ventricular EVM has been demonstrated to reliably identify low-voltage regions ("electroanatomical scar"), which in patients with ARVC/D correspond to areas of fibrofatty myocardial replacement.

METHODS

The study population comprised 27 patients (15 men and 12 women, age 33.9 +/- 8 years) with RVOT tachycardia and no echocardiographic/angiographic evidence of right ventricular (RV) dilation/dysfunction, who underwent EVM and endomyocardial biopsy (EMB) for characterization of ventricular tachycardia (VT) substrate before catheter ablation.

RESULTS

Electroanatomical voltage mapping was normal in 20 of 27 patients (74%, group A), with electrogram voltage >1.5 mV throughout the RV. The other 7 patients (26%, group B) showed >/=1 (1.4 +/- 07) RV electroanatomical scar area(s) (bipolar voltage <0.5 mV) that correlated with fibrofatty myocardial replacement at EMB (p < 0.001). Clinical predictors of RV scar were right precordial QRS prolongation (p < 0.001) and VT inducibility (p = 0.001). Catheter ablation successfully eliminated VT in 18 of 20 patients (90%). During a follow-up of 41 +/- 8 months, 3 of 7 patients (43%) from group B received an implantable defibrillator because of life-threatening ventricular arrhythmias, compared with no patients from group A (p = 0.016).

CONCLUSIONS

An early/minor form of ARVC/D may mimic idiopathic RVOT tachycardia. Electroanatomical voltage mapping is able to identify RVOT tachycardia due to concealed ARVC/D by detecting RVOT electroanatomical scars that correlate with fibrofatty myocardial replacement at EMB and predispose to sudden arrhythmic death.

Arrhythmogenic right ventricular cardiomyopathy/dysplasia

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a heart muscle disease clinically characterized by life-threatening ventricular arrhythmias. Its prevalence has been estimated to vary from 1:2,500 to 1:5,000. ARVC/D is a major cause of sudden death in the young and athletes. The pathology consists of a genetically determined dystrophy of the right ventricular myocardium with fibro-fatty replacement to such an extent that it leads to right ventricular aneurysms. The clinical picture may include: a subclinical phase without symptoms and with ventricular fibrillation being the first presentation; an electrical disorder with palpitations and syncope, due to tachyarrhythmias of right ventricular origin; right ventricular or biventricular pump failure, so severe as to require transplantation. The causative genes encode proteins of mechanical cell junctions (plakoglobin, plakophilin, desmoglein, desmocollin, desmoplakin) and account for intercalated disk remodeling. Familiar occurrence with an autosomal dominant pattern of inheritance and variable penetrance has been proven. Recessive variants associated with palmoplantar keratoderma and woolly hair have been also reported. Clinical diagnosis may be achieved by demonstrating functional and structural alterations of the right ventricle, depolarization and repolarization abnormalities, arrhythmias with the left bundle branch block morphology and fibro-fatty replacement through endomyocardial biopsy. Two dimensional echo, angiography and magnetic resonance are the imaging tools for visualizing structural-functional abnormalities. Electroanatomic mapping is able to detect areas of low voltage corresponding to myocardial atrophy with fibro-fatty replacement. The main differential diagnoses are idiopathic right ventricular outflow tract tachycardia, myocarditis, dialted cardiomyopathy and sarcoidosis. Only palliative therapy is available and consists of antiarrhythmic drugs, catheter ablation and implantable cardioverter defibrillator. Young age, family history of juvenile sudden death, QRS dispersion ≥ 40 ms, T-wave inversion, left ventricular involvement, ventricular tachycardia, syncope and previous cardiac arrest are the major risk factors for adverse prognosis. Preparticipation screening for sport eligibility has been proven to be effective in detecting asymptomatic patients and sport disqualification has been life-saving, substantially declining sudden death in young athletes.