Epsilon Wave in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy

Prognostic Electrocardiographic Signs in Arrhythmogenic Cardiomyopathy

Arrhythmogenic cardiomyopathy (ACM) is a rare cardiac disease, characterized by the progressive replacement of myocardial tissue with fibrous and fatty deposits. It can involve both the right and left ventricles. It is associated with the development of life-threatening arrhythmias and culminates in sudden cardiac death. Electrocardiography (ECG) has emerged as a pivotal tool, offering diagnostic insights and prognostic information. The specific ECG abnormalities observed in ACM not only contribute to early detection but also hold the key to the prediction of the likelihood of severe complications. The recognition of these nuanced ECG manifestations has become imperative for clinicians as it guides them in the formulation of tailored therapeutic strategies that address both the present symptoms and the potential future risks.

Epsilon Waves as an Extreme Form of Depolarization Delay: Focusing on the Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia

Revision of the Task Force diagnostic criteria (TFC) for arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D), in 2010, has increased the sensitivity for the diagnosis of early and familial forms of the disease. Epsilon wave (EW) is a major diagnostic criterion in the context of ARVC/D, however, it remains unquantifiable and therefore, may leave room for substantial subjective interpretation, thus, explaining the existing high inter-observer variability in the assessment of EW. EW, when present, coexists with other disease characteristics, which are sufficient for ARVC/D diagnosis, making EW generally not required for ARVC/D diagnosis. Nevertheless, EW remains an important part of the electrocardiographic phenotype of ARVC/D that may be useful in planning diagnostic work-up, which needs to be recognized.

Electrocardiographic features of the presence of occult myocardial disease in patients with VPD-induced cardiomyopathy

Background

Frequent ventricular premature depolarizations (VPDs) can cause reversible cardiomyopathy (CMP). However, many patients maintain a normal left ventricular (LV) function with a high VPD burden. The electrocardiographic characteristics of VPD‐induced CMP have not been elucidated.

Methods

One hundred and eighty (91 men, age; 51 ± 15 years) patients with frequent idiopathic VPDs (>10% VPDs/day or >10 000 VPDs/day) were studied. All patients underwent successful ablation and were then divided into two groups according to the echocardiographic findings before and after the ablation procedure.

Results

Group A (n = 139) had a normal LV function with VPD frequencies, and Group B (n = 41) had reversible LV dysfunction after ablation. The VPD QRS duration (QRSd) was wider in patients with CMP (Group A vs Group B; 137.2 ± 12.0 milliseconds vs 159.7 ± 5.3 milliseconds, P < .001). VPDs with a terminal QRS delay marked by a notch followed by a discrete lower amplitude signal after the peak R wave in any precordial lead were identified. The incidence of terminal signals was higher in the CMP group (Group A vs Group B; 2.1% vs 53.6%, P < .001).

Conclusions

The wider VPD QRSd and terminal QRS delay in patients with VPD‐induced CMP suggest subclinical cell‐to‐cell conduction abnormalities as a potential factor predisposing VPD‐induced CMP.

Epsilon wave: A review of historical aspects

The epsilon wave of the electrocardiogram (ECG) together with fragmented QRS (fQRS), the terminal conduction delay, incomplete right bundle branch block (IRBBB) and complete/advanced RBBB (CRBBB) of peripheral origin are part of a spectrum of ventricular depolarization abnormalities of arrhythmogenic cardiomyopathy(AC). Although the epsilon wave is considered a major diagnostic criterion for AC since 2010 (AC Task Force Criteria), its diagnostic value is limited because it is a sign of the later stage of the disease. It would be more appropriate to say that the epsilon wave is a “hallmark” of AC, but is of low diagnostic sensitivity. Although the epsilon wave has high specificity for AC, it can be present in other pathological conditions. In this update we will cover the nomenclature, association with disease states and electrocardiographic aspects of the epsilon wave.

Isolated Cardiac Sarcoidosis Mimicking Arrhythmogenic Right Ventricular Cardiomyopathy

The diagnosis of cardiac sarcoidosis (CS) has become easier due to advances in imaging modalities, but we sometimes encounter difficult-to-diagnose patients. We herein report the case of a 60-year-old Japanese woman who was diagnosed with isolated CS, although she also met the diagnostic criteria of arrhythmogenic right ventricular cardiomyopathy (ARVC). A histological examination by an endomyocardial biopsy of the right ventricle revealed the typical findings of granulomatous change for CS. Although she did not show any characteristics of systemic sarcoidosis, oral prednisolone treatment was introduced, and she achieved a good response. This case shows that the characteristics of CS can overlap with the diagnostic criteria of ARVC, and that a histological examination is essential for the correct diagnosis of CS.

Late potentials and their correlation with ventricular structure in patients with ventricular arrhythmias

INTRODUCTION

The presence of late potentials (LP) may indicate a predisposition to ventricular arrhythmias and sudden cardiac death. We investigated the association between presence of LP and structural cardiac anomalies assessed by magnetic resonance (CMR) in patients presenting with ventricular arrhythmias.

METHODS

We included 42 patients admitted with ventricular tachycardia or fibrillation who had undergone both signal-averaged ECG recording and CMR imaging. Clinical data and CMR findings were compared in patients with and without LP.

RESULTS

The majority, 26 (62%) patients, were sudden cardiac death survivors and the remaining 16 (38%) were admitted with ventricular tachycardia. After full diagnostic work-up, the most common diagnoses in the cohort were idiopathic ventricular tachycardia/ventricular fibrillation (25 patients, 60%) or cardiomyopathies (11 patients, 26%). LPs were positive in 29 (69%) when using the revised Task Force criteria. When comparing patients with and without late potentials, there were no significant differences in right ventricular size relative to body surface area (102 mL/m² vs 92 mL/m² ), right ventricular ejection fraction (55% vs 58%), or positive late gadolinium enhancement (29% vs 24%).

CONCLUSIONS

Among patients with malignant arrhythmias, the presence of LP does not distinguish between patients with normal and abnormal RV structure or function on CMR. LP may indicate the presence of an arrhythmic heart disease beyond what can be inferred from CMR. The frequent finding of late potentials indicates that the diagnostic value of LP as an ARVC criteria should be tested in larger studies comparing ARVC patients and controls.

Phenotypic expression of ARVC: How 12 lead ECG can predict left or right ventricle involvement. A familiar case series and a review of literature

AIMS

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart-muscle disease primarily affecting the right ventricle (RV) and potentially causing sudden death in young people. The natural history of the disease is firstly characterized by a concealed form progressing over a biventricular involvement. Three different cases coming from the same family are presented together with a review of the literature.

METHODS AND RESULTS

Multi-parameter analysis including imaging and electrocardiographic analysis is presented since the first medical referral with follow-up ranging from 11 to 38years. Case 1 presented a typical RV involvement in agreement with the ECG pattern. Case 2 presented a prevalent left ventricular involvement leading from the beginning to a pattern of dilated cardiomyopathy in agreement with his ECG evolution over the years. On the other side, Case 3 came to observation with a typical RV involvement (similar to Case 1) but with ECG evolution of typical left ventricle involvement (similar to Case 2). The genetic analysis showed a mutation in desmoglein-2 (DSG2) gene: p. Arg49His. Comparison between size and localization of ventricular dyskinesia at cardiovascular imaging and the surface 12 lead electrocardiography are proposed.

CONCLUSIONS

ARVC may lead to an extreme phenotypic variability in clinical manifestations even within patients coming from the same family in which ARVC is caused by the same genetic mutation. ECG progression over time reflects disease evolution and in particular cases may anticipate wall motion abnormalities by years.

Arrhythmogenic right ventricular cardiomyopathy: ECG progression over time and correlation with long-term follow-up

AIMS

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart muscle disease primarily affecting the right ventricle and potentially causing sudden death in young people. Our aims are to analyse the progression over time of electrocardiographic (ECG) findings and to investigate their prognostic impact.

METHODS

Sixty-eight patients (69% men; age 31 ± 19 years) with ARVC diagnosis were followed up for a mean of 17 ± 8 years. Follow-up included baseline ECG, 24-h Holter ECG, signal-averaged ECG, stress test, echocardiography, cardiac magnetic resonance and electrophysiologic study.

RESULTS

During follow-up 12 (18%) patients died: three of sudden cardiac death (SCD), four of end-stage heart failure and five of noncardiac causes. Aborted SCD occurred in 7 (10%) patients, syncope in 31 (46%), sustained ventricular tachycardia in 43 (63%), heart failure in 18 (26%), atrial fibrillation in 16 (24%) and 3 (4%) patients underwent heart transplant. Twenty-four (35%) patients had implantable cardiac defibrillator (15 and 5 of them received both appropriate and inappropriate interventions, respectively and 7 experienced device-related complications). Of the ECG parameters registered at the enrolment, left anterior fascicular block (P = 0.001), QRS duration in lead 1 (P < 0.001), Epsilon wave (P < 0.001), T wave inversion in V4-V5-V6 (P = 0.012, P = 0.001 and P = 0.006) and low QRS voltages (P = 0.001) progressed over time. At multivariate analysis Epsilon wave (odds ratio 20.9, confidence interval 95% 1.8-239.8, P = 0.015) was the only predictor of the composite endpoint of SCD, heart failure-related death or heart transplant.

CONCLUSION

Apart from playing a pivotal role in ARVC diagnosis, a simple ECG feature such as Epsilon wave is a marker of poor prognosis.

QRS fragmentation: its role in sherlocking the arrhythmogenic heart

The electrocardiogram (ECG) is a commonly available basic diagnostic modality in in-patient, out-patient, and emergency departments. In patients with coronary artery disease (CAD), the presence of a fragmented QRS (f-QRS), which is an extra R wave (R′), notching of the single R wave, notching of the S wave in at least two contiguous leads on the 12-lead ECG, is associated with a myocardial scar from previous myocardial injury. Furthermore, the presence of f-QRS has been shown to be associated with adverse outcomes in CAD and non-CAD patients. In the present paper, we will solely focus on the usefulness and utilization of f-QRS in predicting ventricular tachyarrhythmia in many heart diseases, that is, ischemic cardiomyopathy, non-ischemic cardiomyopathy, hypertrophic obstructive cardiomyopathy, Brugada syndrome, and arrhythmogenic right ventricular cardiomyopathy. In the majority of such cases, ventricular tachyarrhythmia results in sudden cardiac death. Diagnosing them beforehand can lead to prevention and/or early treatment of these arrhythmias to prevent potential morbidity and mortality.

Function of a novel plakophilin-2 mutation in the abnormal expression of connexin43 in a patient with arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a desmosomal disease. Desmosomes and gap junctions are important structural components of cardiac intercalated discs. The proteins plakophilin-2 (PKP-2) and connexin43 (Cx43) are components of desmosomes and gap junctions, respectively. This study was conducted to determine whether Cx43 expression is affected by the mutation of the PKP-2 gene in patients with ARVC. A novel mutation was detected in a typical patient with ARVC. The mutated gene was transfected into rat mesenchymal stem cells expressing Cx43 through a pReversied-M-29 plasmid. Cx43 expression was detected using quantitative polymerase chain reaction analysis. Cx43 expression was significantly decreased in the mutant PKP-2 group compared with that in the wild-type PKP-2 group. In conclusion, PKP-2 affected Cx43 expression at the gene transcription level in the patient with ARVC.

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.

The electrocardiographic manifestations of arrhythmogenic right ventricular dysplasia

The ECG is abnormal in most patients with arrhythmogenic right ventricular dysplasia (ARVD). Right ventricular parietal block, reduced QRS amplitude, epsilon wave, T wave inversion in V1-3 and ventricular tachycardia in the morphology of left bundle branch block are the characteristic changes that reflect the underlying genetic predetermined pathology and pathoelectrophysiology. Recognizing the characteristic ECG changes in ARVD will be of help in making a correct diagnosis of this rare disease.

The presence of epsilon waves in all precordial leads (V1 -V6 ) in a 13-year-old boy with arrhythmogenic right ventricular dysplasia (ARVD)

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

Sudden cardiac death in young athletes: preparticipation screening for underlying cardiovascular abnormalities and approaches to prevention

The study of sudden cardiac death (SCD) in athletes has received more interest in the medical and lay press over the past few years. Professional athletes represent ideals of fitness and health, and the sudden death of prominent athletes can come as a shock. Underlying occult cardiovascular disorders are the most common cause of SCD in athletes. Unfortunately, because these disorders rarely present clinically, their initial manifestation is often a fatal event. Due to this, much attention has turned to both primary and secondary prevention. Primary prevention includes preparticipation screening and secondary prevention includes having automatic external defibrillators available at sporting events. This article summarizes the most common causes of athletic-related cardiac arrest and evaluates the screening methods used to screen for these conditions. The general sentiment is that we need to more effectively identify athletes who are at risk for SCD, but how to do so using an efficient screening system and in a cost-effective manner have not been determined.

The role of cardiac magnetic resonance imaging in the assessment of non-ischemic cardiomyopathy

Cardiovascular magnetic resonance imaging (CMR) plays an increasing role in the assessment of patients with various cardiovascular disorders. Given its enhanced spatial resolution, improved tissue characterization, and lack of ionizing radiation, it has become the test of choice in the evaluation of patients with new-onset cardiomyopathy of unknown etiology. In this paper, we will review the role of CMR in the evaluation of patients with various types of non-ischemic cardiomyopathy.

Value of the signal-averaged electrocardiogram in arrhythmogenic right ventricular cardiomyopathy/dysplasia

BACKGROUND

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is an inherited disease that causes structural and functional abnormalities of the right ventricle (RV). The presence of late potentials as assessed by the signal-averaged electrocardiogram (SAECG) is a minor task force criterion.

OBJECTIVE

The purpose of this study was to examine the diagnostic and clinical value of the SAECG in a large population of genotyped ARVC/D probands.

METHODS

We compared the SAECGs of 87 ARVC/D probands (age 37 ± 13 years, 47 males) diagnosed as affected or borderline by task force criteria without using the SAECG criterion with 103 control subjects. The association of SAECG abnormalities was also correlated with clinical presentation, surface ECG, ventricular tachycardia (VT) inducibility at electrophysiologic testing, implantable cardioverter-defibrillator therapy for VT, and RV abnormalities as assessed by cardiac magnetic resonance imaging (cMRI).

RESULTS

Compared with controls, all three components of the SAECG were highly associated with the diagnosis of ARVC/D (P <.001). They include the filtered QRS duration (97.8 ± 8.7 ms vs 119.6 ± 23.8 ms), low-amplitude signal (24.4 ± 9.2 ms vs 46.2 ± 23.7 ms), and root mean square amplitude of the last 40 ms of the QRS (50.4 ± 26.9 μV vs 27.9 ± 36.3 μV). The sensitivity of using SAECG for diagnosis of ARVC/D was increased from 47% using the established 2 of 3 criteria (i.e., late potentials) to 69% by using a modified criterion of any 1 of 3 criteria, while maintaining a high specificity of 95%. Abnormal SAECG as defined by this modified criterion was associated with a dilated RV volume and decreased RV ejection fraction detected by cMRI (P <.05). SAECG abnormalities did not vary with clinical presentation or reliably predict spontaneous or inducible VT and had limited correlation with ECG findings.

CONCLUSION

Using 1 of 3 SAECG criteria contributed to increased sensitivity and specificity for the diagnosis of ARVC/D. This finding is incorporated in the recent modification of the task force criteria.

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.