The electrocardiographic manifestations of arrhythmogenic right ventricular dysplasia

Cardiac conduction disorders in young adults: Clinical characteristics and genetic background of an underestimated population

BACKGROUND

Cardiac conduction disorder (CCD) in patients <50 years old is a rare and mostly unknown condition.

OBJECTIVE

We aimed to assess clinical characteristics and genetic background of patients <50 years old with CCD of unknown origin.

METHODS

We retrospectively reviewed a consecutive series of patients with a diagnosis of CCD before the age of 50 years referred to our center between January 2019 and December 2021. Patients underwent complete clinical examination and genetic evaluation.

RESULTS

We enrolled 39 patients with a median age of 40 years (28-47 years) at the onset of symptoms. A cardiac implantable electronic device was implanted in 69% of the patients. In 15 of 39 CCD index patients (38%), we found a total of 13 different gene variations (3 pathogenic, 6 likely pathogenic, and 4 variants of uncertain significance), mostly in 3 genes (SCN5A, TRPM4, and LMNA). In our cohort, genetic testing led to the decision to implant an implantable cardioverter-defibrillator in 2 patients for the increased risk of sudden cardiac death.

CONCLUSION

Patients with the occurrence of CCD before the age of 50 years present with a high rate of pathologic gene variations, mostly in 3 genes (SCN5A, TRPM4, and LMNA). The presence of pathogenic variations may add information about the prognosis and lead to an individualized therapeutic approach.

Electrocardiographic predictors of left ventricular scar in athletes with right bundle branch block premature ventricular beats

AIMS

Right bundle branch block (RBBB) morphology non-sustained ventricular arrhythmias (VAs) have been associated with the presence of non-ischaemic left ventricular scar (NLVS) in athletes. The aim of this cross-sectional study was to identify clinical and electrocardiogram (ECG) predictors of the presence of NLVS in athletes with RBBB VAs.

METHODS AND RESULTS

Sixty-four athletes [median age 39 (24-53) years, 79% males] with non-sustained RBBB VAs underwent cardiac magnetic resonance (CMR) with late gadolinium enhancement in order to exclude the presence of a concealed structural heart disease. Thirty-six athletes (56%) showed NLVS at CMR and were assigned to the NLVS positive group, whereas 28 athletes (44%) to the NLVS negative group. Family history of cardiomyopathy and seven different ECG variables were statistically more prevalent in the NLVS positive group. At univariate analysis, seven ECG variables (low QRS voltages in limb leads, negative T waves in inferior leads, negative T waves in limb leads I-aVL, negative T waves in precordial leads V4-V6, presence of left posterior fascicular block, presence of pathologic Q waves, and poor R-wave progression in right precordial leads) proved to be statistically associated with the finding of NLVS; these were grouped together in a score. A score ≥2 was proved to be the optimal cut-off point, identifying NLVS athletes in 92% of cases and showing the best accuracy (86% sensitivity and 100% specificity, respectively). However, a cut-off ≥1 correctly identified all patients with NLVS (absence of false negatives).

CONCLUSION

In athletes with RBBB morphology non-sustained VAs, specific ECG abnormalities at 12-lead ECG can help in detecting subjects with NLVS at CMR.

Management of Arrhythmias in the Cardiovascular Intensive Care Unit

Arrhythmias in the cardiovascular intensive care unit (CVICU) can be difficult to manage because of the complex hemodynamic and respiratory states of critically ill patients. Treating physicians must be educated to prevent, diagnose, and treat a multitude of tachyarrhythmias and bradyarrhythmias. In this review article, the authors outline a pragmatic approach to patient assessment, arrhythmia diagnosis, and management of the most common arrhythmias seen in the CVICU.

Brugada syndrome and job fitness: report of three cases

Brugada syndrome (BrS) is an inherited arrhythmogenic disorder predisposing patients to a high risk of sudden cardiac death. Specific guidelines on the health surveillance of BrS workers are lacking. We report here three cases requiring assessment of specific job capacity, investigated with an interdisciplinary protocol including 24-h Holter electrocardiography with modified precordial leads, pharmacological test with ajmaline, molecular genetic analysis, electrophysiological study with ventricular stimulation, risk stratification, and occupational medicine evaluation: (1) a female 42-yr-old company manager with positive ajmaline test and CACNA1C gene mutation (judged fit for the job with limitations regarding work-related stress); (2) a male 44-yr-old welder with positive ajmaline test, SCN5A gene mutation, and associated OSAS (obstructive sleep apnea syndrome), who was advised to refrain from night shifts and driving company vehicles; (3) a male 45-yr-old electrical technician with inducible ventricular tachyarrhythmia, who was implanted with a biventricular cardioverter defibrillator, and therefore recommended to avoid exposure to electromagnetic fields and working at heights. We conclude that the collaboration between the cardiologist and the occupational physician allows defining the functional capabilities and the arrhythmogenic risk of BrS workers, to optimize job fitness assessment.

Arrhythmogenic right ventricular cardiomyopathy mimicking Brugada - a case report

We report a rare case of arrhythmogenic right ventricular cardiomyopathy (ARVC). Middle-aged Kuwaiti gentleman presented to a polyclinic with complaints of dizziness and palpitation. Electrocardiogram (ECG) at the polyclinic showed polymorphic ventricular tachycardia, and hence he was referred to our center. ECG at the emergency room showed a Brugada pattern with epsilon waves. Echo showed right ventricular dysfunction with pulmonary arterial hypertension. Magnetic resonance imaging showed evidence of ARVC. He was referred to the electrophysiology team and implanted an implantable cardioverter-defibrillator electively.

The phenotypic and genetic features of arrhythmogenic cardiomyopathy in the pediatric population

Introduction

The present study aimed to describe the phenotypic features and genetic spectrum of arrhythmogenic cardiomyopathy (ACM) presented in childhood and test the validity of different diagnostic approaches using Task Force Criteria 2010 (TFC) and recently proposed Padua criteria.

Patients and methods

Thirteen patients (mean age at diagnosis 13.6 ± 3.7 years) were enrolled using "definite" or "borderline" diagnostic criteria of ACM according to the TFC 2010 and the Padua criteria in patients <18 years old. Clinical data, including family history, 12-lead electrocardiogram (ECG), signal-averaged ECG, 24-h Holter monitoring, imaging techniques, genetic testing, and other relevant information, were collected.

Results

All patients were classified into three variants: ACM of right ventricle (ACM-RV; n = 6, 46.1%), biventricular ACM (ACM-BV; n = 3, 23.1%), and ACM of left ventricle (ACM-LV; n = 4, 30.8%). The most common symptoms at presentations were syncope (n = 6; 46.1%) and palpitations (n = 5; 38.5%). All patients had more than 500 premature ventricular contractions per day. Ventricular tachycardia was reported in 10 patients (76.9%), and right ventricular dilatation was registered in 8 patients (61.5%). An implantable cardiac defibrillator was implanted in 61.5% of cases, and three patients with biventricular involvement underwent heart transplantation. Desmosomal mutations were identified in 8 children (53.8%), including four patients with PKP2 variants, two with DSP variants, one with DSG2 variant, and one with JUP. Four patients carried compound heterozygous variants in desmosomal genes associated with left ventricular involvement.

Conclusion

Arrhythmias and structural heart disease, such as chamber dilatation, should raise suspicion of different ACM phenotypes. Diagnosis of ACM might be difficult in pediatric patients, especially for ACM-LV and ACM-BV forms. Our study confirmed that using "Padua criteria" in combination with genetic testing improves the diagnostic accuracy of ACM in children.

Electrocardiogram in arrhytmogenic cardiomyopathy

Criteria for diagnosis of arrhythmogenic cardiomyopathy (ACM) were first proposed in 1994 and subsequently revised in 2010 and in 2020 by an international task force. According to the last consensus of 2020, ACM is defined as a heart muscle disease affecting right ventricle, left ventricle or both, whose principal pathologic feature is fibrofatty myocardial replacement that impairs systolic ventricular function and predisposes to lethal ventricular arrhythmias. ECG findings not only could help to early recognize affected patients but also could identify the ones with maximum risk of ventricular arrhythmias and sudden cardiac death.

Desmosomal protein degradation as an underlying cause of arrhythmogenic cardiomyopathy

Arrhythmogenic cardiomyopathy (ACM) is an inherited progressive cardiac disease. Many patients with ACM harbor mutations in desmosomal genes, predominantly in plakophilin-2 (PKP2). Although the genetic basis of ACM is well characterized, the underlying disease-driving mechanisms remain unresolved. Explanted hearts from patients with ACM had less PKP2 compared with healthy hearts, which correlated with reduced expression of desmosomal and adherens junction (AJ) proteins. These proteins were also disorganized in areas of fibrotic remodeling. In vitro data from human-induced pluripotent stem cell-derived cardiomyocytes and microtissues carrying the heterozygous PKP2 c.2013delC pathogenic mutation also displayed impaired contractility. Knockin mice carrying the equivalent heterozygous Pkp2 c.1755delA mutation recapitulated changes in desmosomal and AJ proteins and displayed cardiac dysfunction and fibrosis with age. Global proteomics analysis of 4-month-old heterozygous Pkp2 c.1755delA hearts indicated involvement of the ubiquitin-proteasome system (UPS) in ACM pathogenesis. Inhibition of the UPS in mutant mice increased area composita proteins and improved calcium dynamics in isolated cardiomyocytes. Additional proteomics analyses identified lysine ubiquitination sites on the desmosomal proteins, which were more ubiquitinated in mutant mice. In summary, we show that a plakophilin-2 mutation can lead to decreased desmosomal and AJ protein expression through a UPS-dependent mechanism, which preceded cardiac remodeling. These findings suggest that targeting protein degradation and improving desmosomal protein stability may be a potential therapeutic strategy for the treatment of ACM.

Syncope in the athlete - Minor changes, major diagnosis!

We report the case of a 17-year-old athlete who resorted to the emergency department for palpitations and dizziness while exercising. He mentioned two exercise-associated episodes of syncope in the last six months. He was tachycardic and hypotensive. The electrocardiogram showed regular wide complex tachycardia, left bundle branch block morphology with superior axis restored to sinus rhythm after electrical cardioversion. In sinus rhythm, it showed T-wave inversion in V1-V5. Transthoracic echocardiography revealed mild dilation and dysfunction of the right ventricle (RV) with global hypocontractility. Cardiac magnetic resonance (CMR) revealed a RV end diastolic volume indexed to body surface area of 180 ml/m², global hypokinesia and RV dyssynchrony, subepicardial late enhancement in the distal septum and in the middle segment of the inferoseptal wall. The patient underwent a genetic study which showed a mutation in the gene that encodes the desmocolin-2 protein (DSC-2), which is involved in the pathogenesis of arrhythmogenic right ventricular cardiomyopathy (ARVC). According to the modified Task Force Criteria for this diagnosis, the patient presented four major criteria for ARVC. Thus, a subcutaneous cardioverter was implanted, and the patient was followed up at the cardiology department. Arrhythmogenic right ventricular cardiomyopathy diagnosis is based on structural, functional, electrophysiological and genetic criteria reflecting underlying histological changes. This case depicts the essential characteristics for disease recognition.

Role of genetic testing in young patients with idiopathic atrioventricular conduction disease

AIMS

To investigate the role of genetic testing in patients with idiopathic atrioventricular conduction disease requiring pacemaker (PM) implantation before the age of 50 years.

METHODS AND RESULTS

All consecutive PM implantations in Southern Switzerland between 2010 and 2019 were evaluated. Inclusion criteria were: (i) age at the time of PM implantation: < 50 years; (ii) atrioventricular block (AVB) of unknown aetiology. Study population was investigated by ajmaline challenge and echocardiographic assessment over time. Genetic testing was performed using next-generation sequencing panel, containing 174 genes associated to inherited cardiac diseases, and Sanger sequencing confirmation of suspected variants with clinical implication. Of 2510 patients who underwent PM implantation, 15 (0.6%) were young adults (median age: 44 years, male predominance) presenting with advanced AVB of unknown origin. The average incidence of idiopathic AVB computed over the 2010-2019 time window was 0.7 per 100 000 persons per year (95% CI 0.4-1.2). Most of patients (67%) presented with specific genetic findings (pathogenic variant) or variants of uncertain significance (VUS). A pathogenic variant of PKP2 gene was found in one patient (6.7%) with no overt structural cardiac abnormalities. A VUS of TRPM4, MYBPC3, SCN5A, KCNE1, LMNA, GJA5 genes was found in other nine cases (60%). Of these, three unrelated patients (20%) presented the same heterozygous missense variant c.2531G > A p.(Gly844Asp) in TRPM4 gene. Diagnostic re-assessment over time led to a diagnosis of Brugada syndrome and long-QT syndrome in two patients (13%). No cardiac events occurred during a median follow-up of 72 months.

CONCLUSION

Idiopathic AVB in adults younger than 50 years is a very rare condition with an incidence of 0.7 per 100 000 persons/year. Systematic investigations, including genetic testing and ajmaline challenge, can lead to the achievement of a specific diagnosis in up to 20% of patients. Heterozygous missense variant c.2531G > A p.(Gly844Asp) in TRPM4 gene was found in an additional 20% of unrelated patients, suggesting possible association of the variant with the disease.

Analysis of digitalized ECG signals based on artificial intelligence and spectral analysis methods specialized in ARVC

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart muscle disease that appears between the second and forth decade of a patient's life, being responsible for 20% of sudden cardiac deaths before the age of 35. The effective and punctual diagnosis of this disease based on electrocardiograms (ECGs) could have a vital role in reducing premature cardiovascular mortality. In our analysis, we first outline the digitalization process of paper-based ECG signals enhanced by a spatial filter aiming to eliminate dark regions in the dataset's images that do not correspond to ECG waveform, producing undesirable noise. Next, we propose the utilization of a low-complexity convolutional neural network for the detection of an arrhythmogenic heart disease, that has not been studied through the usage of deep learning methodology to date, achieving high classification accuracy, namely 99.98% training and 98.6% testing accuracy, on a disease the major identification criterion of which are infinitesimal millivolt variations in the ECG's morphology, in contrast with other arrhythmogenic abnormalities. Finally, by performing spectral analysis we investigate significant differentiations in the field of frequencies between normal ECGs and ECGs corresponding to patients suffering from ARVC. In 16 out of the 18 frequencies where we encounter statistically significant differentiations, the normal ECGs are characterized by greater normalized amplitudes compared to the abnormal ones. The overall research carried out in this article highlights the importance of integrating mathematical methods into the examination and effective diagnosis of various diseases, aiming to a substantial contribution to their successful treatment.

A case of mistaken arrhythmogenic identity during pregnancy

Atypical LVOT ectopy can present with an RVOT morphology on ECG and differentiation to reveal this focus is in favor of benign idiopathic ventricular ectopy over an arrhythmogenic cardiomyopathy.

Loss of Consciousness in the Young Child

In the very young child (less than eight years of age), transient loss of consciousness represents a diagnostic and management dilemma for clinicians. While most commonly benign, syncope may be due to cardiac dysfunction which can be life-threatening. It can be secondary to an underlying ion channelopathy, cardiac inflammation, cardiac ischemia, congenital heart disease, cardiomyopathy, or pulmonary hypertension. Patients with genetic disorders require careful evaluation for a cardiac cause of syncope. Among the noncardiac causes, vasovagal syncope is the most common etiology. Breath-holding spells are commonly seen in this age group. Other causes of transient loss of consciousness include seizures, neurovascular pathology, head trauma, psychogenic pseudosyncope, and factitious disorder imposed on another and other forms of child abuse. A detailed social, present, past medical, and family medical history is important when evaluating loss of consciousness in the very young. Concerning characteristics of syncope include lack of prodromal symptoms, no preceding postural changes or occurring in a supine position, after exertion or a loud noise. A family history of sudden unexplained death, ion channelopathy, cardiomyopathy, or congenital deafness merits further evaluation. Due to inherent challenges in diagnosis at this age, often there is a lower threshold for referral to a specialist.

Emergency department extracorporeal membrane oxygenation as a rescue therapy for ventricular tachycardia electrical storm: a case report

Arrhythmogenic right ventricular cardiomyopathy is a cause of sudden cardiac death in often otherwise healthy young adults. Cardiac arrest following an unstable tachydysrhythmia may be the primary presenting symptom. Venous arterial extracorporeal life support via extracorporeal membrane oxygenation (VA ECMO) has been used as a rescue strategy in emergency departments (EDs) for patients with cardiac arrest unresponsive to conventional cardiopulmonary resuscitation. We present a case of a previously healthy 18-year-old male who presented to our emergency department with ECG features of arrhythmogenic right ventricular cardiomyopathy and subsequent pulseless polymorphic ventricular tachycardia refractory cardiac arrest, treated with ED-initiated VA ECMO.

Clinical Presentation, Cardiac Magnetic Resonance Findings, and Prognosis of Patients with Arrhythmogenic Right Ventricular Cardiomyopathy - An Experience from Pakistan

Objectives:

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart-muscle disease, characterized by fibro-fatty replacement and ventricular arrhythmias, that primarily affects the right ventricle (RV). We aimed to look at the clinical presentation, cardiac magnetic resonance (CMR) imaging findings and prognosis of patients with ARVC in Pakistan.

Material and Methods:

It is a retrospective observational study, 17 consecutive patients with CMR and other findings consistent with ARVC, were enrolled from 2010 to 2019 at a single center.

Results:

Out of 17 patients, 12 (70.6%) were male with a mean age of 33.5 ± 17.5 years. Family history of sudden cardiac death was present in 3 (17.7%) patients while one (5.9%) patient had family history of ARVC. Syncope was the first presenting symptom in eight (47.1%) patients. On 12 leads ECG, T wave inversion in precordial leads was found in 6 (35.4%) patients, and epsilon wave was present in only 3 (17.7%) patients. On echocardiogram, 13 (76.5%) patients had dilated RV with reduced systolic function. On CMR, majority of patients (n = 14, 82.4%) were found to have RV dilatation with regional dyskinesia and fatty infiltration, 9 (52.9%) of them had left ventricular involvement also. Follow-up was available for 14 patients (82.4%) with a mean follow-up period of 35.5 ± 19.7 months. Three (21.4%) of them died and 10 (71.4%) got admissions for heart failure during follow-up period.

Conclusion:

Arrhythmia related events are the main presenting symptoms of ARVC in this region, and left ventricular involvement in ARVC is not rare in this population. The mortality is relatively high, probably due to advanced disease at the time of presentation and less medical facilities available.

Molecular mechanisms of arrhythmogenic cardiomyopathy

Arrhythmogenic cardiomyopathy is a genetic disorder characterized by the risk of life-threatening arrhythmias, myocardial dysfunction and fibrofatty replacement of myocardial tissue. Mutations in genes that encode components of desmosomes, the adhesive junctions that connect cardiomyocytes, are the predominant cause of arrhythmogenic cardiomyopathy and can be identified in about half of patients with the condition. However, the molecular mechanisms leading to myocardial destruction, remodelling and arrhythmic predisposition remain poorly understood. Through the development of animal, induced pluripotent stem cell and other models of disease, advances in our understanding of the pathogenic mechanisms of arrhythmogenic cardiomyopathy over the past decade have brought several signalling pathways into focus. These pathways include canonical and non-canonical WNT signalling, the Hippo-Yes-associated protein (YAP) pathway and transforming growth factor-β signalling. These studies have begun to identify potential therapeutic targets whose modulation has shown promise in preclinical models. In this Review, we summarize and discuss the reported molecular mechanisms underlying the pathogenesis of arrhythmogenic cardiomyopathy.

Clinical Diagnosis, Imaging, and Genetics of Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia: JACC State-of-the-Art Review

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is an inherited cardiomyopathy that can lead to sudden cardiac death and heart failure. Our understanding of its pathophysiology and clinical expressivity is continuously evolving. The diagnosis of ARVC/D remains particularly challenging due to the absence of specific unique diagnostic criteria, its variable expressivity, and incomplete penetrance. Advances in genetics have enlarged the clinical spectrum of the disease, highlighting possible phenotypes that overlap with arrhythmogenic dilated cardiomyopathy and channelopathies. The principal challenges for ARVC/D diagnosis include the following: earlier detection of the disease, particularly in cases of focal right ventricular involvement; differential diagnosis from other arrhythmogenic diseases affecting the right ventricle; and the development of new objective electrocardiographic and imaging criteria for diagnosis. This review provides an update on the diagnosis of ARVC/D, focusing on the contribution of emerging imaging techniques, such as echocardiogram/magnetic resonance imaging strain measurements or computed tomography scanning, new electrocardiographic parameters, and high-throughput sequencing.

Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia (ARVC/D) - What We Have Learned after 40 Years of the Diagnosis of This Clinical Entity

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) was initially recognized as a clinical entity by Fontaine and Marcus, who evaluated a group of patients with ventricular tachyarrhythmia from a structurally impaired right ventricle (RV). Since then, there have been significant advances in the understanding of the pathophysiology, manifestation and clinical progression, and prognosis of the pathology. The identification of genetic mutations impairing cardiac desmosomes led to the inclusion of this entity in the classification of cardiomyopathies. Classically, ARVC/D is an inherited disease characterized by ventricular arrhythmias, right and / or left ventricular dysfunction; and fibro-fatty substitution of cardiomyocytes; its identification can often be challenging, due to heterogeneous clinical presentation, highly variable intra- and inter-family expressiveness, and incomplete penetrance.

In the absence of a gold standard that allows the diagnosis of ARVC/D, several diagnostic categories were combined and recently reviewed for a higher diagnostic sensitivity, without compromising the specificity. The finding that electrical abnormalities, particularly ventricular arrhythmias, usually precede structural abnormalities is extremely important for risk stratification in positive genetic members. Among the complementary exams, cardiac magnetic resonance imaging (CMR) allows the early diagnosis of left ventricular impairment, even before morpho-functional abnormalities. Risk stratification remains a major clinical challenge, and antiarrhythmic drugs, catheter ablation and implantable cardioverter defibrillator are the currently available therapeutic tools. The disqualification of the sport prevents cases of sudden death because the effort can trigger not only the electrical instability, but also the onset and progression of the disease.

Diagnostic and therapeutic strategies for arrhythmogenic right ventricular dysplasia/cardiomyopathy patient

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is a rare inherited heart muscle disease characterized by ventricular tachyarrhythmia, predominant right ventricular dysfunction, and sudden cardiac death. Its pathophysiology involves close interaction between genetic mutations and exposure to physical activity. Mutations in genes encoding desmosomal protein are the most common genetic basis. Genetic testing plays important roles in diagnosis and screening of family members. Syncope, palpitation, and lightheadedness are the most common symptoms. The 2010 Task Force Criteria is the standard for diagnosis today. Implantation of a defibrillator in high-risk patients is the only therapy that provides adequate protection against sudden death. Selection of patients who are best candidates for defibrillator implantation is challenging. Exercise restriction is critical in affected individuals and at-risk family members. Antiarrhythmic drugs and ventricular tachycardia ablation are valuable but palliative components of the management. This review focuses on the current diagnostic and therapeutic strategies in ARVD/C and outlines the future area of development in this field.

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.

MATERIALS AND METHODS

All patients met Task Force 2010 definite ARVD/C criteria. ARVD/C patients without Task Force depolarization/repolarization criteria (-ECG) were compared to controls. Electrocardiogram measures of QRS duration, corrected QT interval, and measured angle between the upslope and downslope of the S-wave in V2, were assessed.

RESULTS

Definite ARVD/C was present in 155 patients (42.7 ± 17.3 years, 68.4%male). -ECG ARVD/C patients (66 patients) were compared to 66 control patients (41.8 ± 17.6 years, 65.2%male). Only the S-wave angle differentiated -ECG ARVD/C patients from controls (<0.001) with AU the ROC curve of 0.77 (95%CI 0.53 to 0.71) and odds ratio of 28.3 (95%CI 6.4 to 125.5).

CONCLUSION

ARVD/C may lead to development of subtle ECG abnormalities distinguishable using the S-wave angle prior to development of 2010 Taskforce ECG criteria.

Epsilon waves: Milestones in the discovery and progress

The Epsilon wave was first identified in 1977. Four decades of progress help people to better understand its pathological electrogenesis and diagnostic value. Currently, the Epsilon wave is on the list of the 2010 Task Force recommendations for the diagnosis of arrhythmogenic right ventricular dysplasia (ARVD). In this review, we provide the history of the first recording of the Epsilon wave in coronary artery disease and Uhl's anomaly, subsequently leading to the signal averaging technique to record late potentials. Based on our experience, we discuss some existing controversies. When we look back at the decades of progress of the Epsilon wave, we conclude that the Epsilon wave is only the tip of the iceberg of ECG abnormalities in ARVD.

Epsilon wave on an electronic loop in a case of arrhythmogenic right ventricular dysplasia with myocarditis: an updated definition of the Epsilon wave

A young man presented with a history of myocarditis with palpitations and dizziness. He had implantation of a loop recorder that showed repetitive short episodes of VT. In addition, there were fragmented potentials immediately following the large and sharp electrograms (EGMs) before as well as after episodes of VT suggesting an Epsilon wave. This signal can be observed in multiple cardiac conditions including coronary artery disease. It was originally recorded on the epicardium as well as on the endocardium. However, in ARVD it can be defined as an electric signal observed after the end of the QRS complex in the right as opposed to the left precordial leads (difference ≥ 25 ms). It can also be an aid to the diagnosis of patients with ARVD who have other signs or symptoms suggesting ARVD including episodes of myocarditis. This potential consists of a slurring at the end of the QRS complex or an independent potential after the return to the isoelectric line. It can be better observed by increasing amplification of the ECG tracing as well as double speed using the Fontaine lead system. Epsilon wave too small to be recorded on the standard ECG can be extracted by Signal Averaging ECG SAECG).

Value of a novel 16-lead High-Definition ECG machine to detect conduction abnormalities in structural heart disease

BACKGROUND

Depolarization abnormalities are hardly detectable by standard 12-lead electrocardiogram (ECG) in some patients.

OBJECTIVE

To evaluate the value of the 16-lead High-Definition (HD)-ECG machine to record conduction abnormalities including Epsilon waves in patients with structural heart disease.

METHODS

Tracings with 12-lead ECG, 16-lead HD-ECG, and signal-averaged ECG were studied.

RESULTS

(1) Case of severe coronary artery disease (CAD): On 16-lead HD-ECG, a tiny intra-QRS signal was noted in lead III, a prolonged P wave in lead II, and fragmentation on top of lead aVL and lead aVF. Proper automatic measurement of the prolonged P wave measuring 190 ms was noted. Signal-averaging by 16-lead HD-ECG in lead III showed the intra-QRS fragmentation and P wave prolongation of 180 ms. (2) First patient with arrhythmogenic right ventricular dysplasia (ARVD): Standard 12-lead ECG indicated Epsilon waves in lead III, V2, V3, and inverted T waves in V1-V3. 16-lead HD-ECG indicated QRS prolongation in lead II, III, aVL, aVF, V2, V3 as opposed to V6, and low amplitudes of QRS complexes in V4R and V3R as a new possible sign of ARVD. Notches in lead V2, widening of QRS complexes in all precordial leads, but shorter QRS in V8-V9 are also considered as a potential new diagnostic sign of ARVD. (3) Second ARVD patient: Notches at the end of the QRS in lead III and a negative initial deflection of the QRS in V1 and V2 were detected by standard 12-lead ECG. On 16-lead HD-ECG, a more pronounced QRS fragmentation was visible.

CONCLUSION

16-lead HD-ECG in both CAD and ARVD seems to be more sensitive than 12-lead ECG to record electrocardiographic abnormalities.

[Arrhythmogenic right ventricular cardiomyopathy/dysplasia. Literature review and case report]

Arrhythmogenic right ventricular cardiomyopathy/dysplasia is an inherited autosomal dominant disease, with an estimated prevalence of 1:2,500 to 1:5,000, being higher in males (3:1). It is characterised histologically by the substitution of cardiomyocytes for fibrous-adipose tissue, which predisposes to ventricular arrhythmias, right ventricular failure, and sudden cardiac death. The main aim of treatment is to reduce the risk of sudden death and improve the quality of life of patients. The case is presented of a 23 year old woman whose clinical symptoms started with palpitations, chest pain with physical activity, syncope, and headache, 6 years ago during her first pregnancy. Due to an increase in symptomatology, a stress test was performed, during which she collapsed with a sustained monomorphic ventricular tachycardia. A cardiac magnetic resonance scan showed dilation, an increase in trabeculae, and decreased function of the right ventricle. A 3-dimensional mapping and ablation was performed, and during the isoproterenol infusion test, a polymorphic ventricular flutter was generated that required electrical cardioversion. The decision was made to implant a dual chamber cardioverter defibrillator and perform stellate ganglion ablation as secondary prevention. After her discharge, the patient re-consulted many times due to discharges of the device associated with palpitations. A comprehensive review of the patient's medical records was performed, finding characteristics that may suggest arrhythmogenic right ventricular dysplasia. The Task Force criteria was applied, concluding that, as she met more than 2 major criteria, the patient had a definitive diagnosis of this disease.

Arrhythmogenic ventricular cardiomyopathy and sudden cardiac death: Left or right?

Arrhythmogenic right ventricular cardiomyopathy is a leading cause of sudden cardiac death among athletes in Italy and the Mediterranean region. Although it often involves the right ventricle causing scarring, dilation, systolic impairment with aneurysm formation, it can also involve the left ventricle or present as isolated left ventricular cardiomyopathy. Cardiac magnetic resonance imaging is considered the gold standard in confirming the diagnosis. We summarize four cases of arrhythmogenic ventricular cardiomyopathy with different presentations observed over the past 2 years.

Mid-ventricular Hypertrophic Obstructive Cardiomyopathy with Apical Aneurysm Complicated with Syncope by Sustained Monomorphic Ventricular Tachycardia

Mid-ventricular hypertrophic obstructive cardiomyopathy with secondary formation of apical aneurysm is a rare variant of hypertrophic cardiomyopathy. They have a unique behavior because unlike other variants it causes sustained monomorphic ventricular tachycardia, which makes it particularly severe.

Arrhythmogenic Right Ventricular Dysplasia in Neuromuscular Disorders

OBJECTIVES

Arrhythmogenic right ventricular dysplasia (ARVD) is a rare, genetic disorder predominantly affecting the right ventricle. There is increasing evidence that in some cases, ARVD is due to mutations in genes, which have also been implicated in primary myopathies. This review gives an overview about myopathy-associated ARVD and how these patients can be managed.

METHODS

A literature review was done using appropriate search terms.

RESULTS

The myopathy, which is most frequently associated with ARVD, is the myofibrillar myopathy due to desmin mutations. Only in a single patient, ARVD was described in myotonic dystrophy type 1. However, there are a number of genes causing either myopathy or ARVD. These genes include lamin A/C, ZASP/cypher, transmembrane protein-43, titin, and the ryanodine receptor-2 gene. Diagnosis and treatment are identical for myopathy-associated ARVD and nonmyopathy-associated ARVD.

CONCLUSIONS

Patients with primary myopathy due to mutations in the desmin, dystrophia myotonica protein kinase, lamin A/C, ZASP/cypher, transmembrane protein-43, titin, or the ryanodine receptor-2 gene should be screened for ARVD. Patients carrying a pathogenic variant in any of these genes should undergo annual cardiological investigations for cardiac function and arrhythmias.

Right Ventricular Outflow Tract Tachycardia with Structural Abnormalities of the Right Ventricle and Left Ventricular Diverticulum

A 43-year-old woman presented to the emergency room with a sustained ventricular tachycardia (VT). ECG showed a QRS in left bundle branch block morphology with inferior axis. Echocardiography, ventricular angiography, and cardiac magnetic resonance imaging (CMRI) revealed a normal right ventricle and a left ventricular diverticulum. Electrophysiology studies with epicardial voltage mapping identified a large fibrotic area in the inferolateral layer of the right ventricular wall and a small area of fibrotic tissue at the anterior right ventricular outflow tract. VT ablation was successfully performed with combined epicardial and endocardial approaches.