Arrhythmogenic left ventricular cardiomyopathy

Ventricular predominance in biventricular arrhythmogenic cardiomyopathy: Should new subtype criteria be recognized?

Arrhythmogenic cardiomyopathy is a biventricular disease in which the effect on the left ventricle can be either equivalent to or more severe than that on the right ventricle. It is a rare disease due to its low reported prevalence and typically becomes clinically evident during the second to fourth decade of life. It represents 4% of sudden cardiac death cases referred for autopsy and 10% of cases of unexplained cardiac arrest. We present a challenging case report of a 68-year-old man who arrived at the emergency room with chest discomfort, palpitations, and light-headedness before a syncopal episode with urinary incontinence. During monitoring, ventricular tachycardia was detected and was treated with cardioversion. However, a follow-up electrocardiogram revealed low QRS voltages in limb leads and T-wave inversion in the left precordial leads. The patient underwent a transthoracic echocardiogram and a gadolinium-based magnetic resonance imaging study to evaluate the possibility of acute decompensated heart failure. Both imaging studies revealed low ejection fraction and systolic dysfunction in both right and left ventricles. Furthermore, in the late gadolinium enhancement study, extensive left ventricular subepicardial enhancement with septal predominance in a ring pattern and an irregular morphology of the right ventricular free wall were observed. A diagnosis of biventricular arrhythmogenic cardiomyopathy was established based on the 2020 Padua Criteria. Although there is not a recognized classification within these criteria to establish its subtype, in our case there was a left ventricular predominance due to the presence of additional left ventricular categories.

Description of the Two-Dimensional Layer-Specific Strain Echocardiography Phenotype of Arrhythmogenic Left Ventricular Cardiomyopathy

BACKGROUND

Arrhythmogenic left ventricular cardiomyopathy (ALVC) is characterized by fibrofatty myocardial replacement demonstrated on cardiac magnetic resonance by late gadolinium enhancement (LGE) mainly involving the subepicardium. The aims of this study were to describe the layer-specific strain (LSS) echocardiography phenotype of ALVC and to compare it with LGE features.

METHODS

All consecutive ALVC pathogenic genetic variant carriers and noncarrier relatives were separated into four prespecified groups (overt ALVC [group 1], isolated LGE [group 2], pathogenic genetic variant carrier without ALVC phenotype [group 3], and no genetic variant carrier [group 4]) and studied accordingly using cardiac magnetic resonance and LSS echocardiography.

RESULTS

Eighty-five individuals were included. Endocardial global longitudinal strain (GLS)-epicardial GLS (GLSepi) gradient was altered predominantly in group 1, illustrating transmural strain alteration in overt ALVC (3.8 ± 1.1 in group 1, 4.3 ± 2.2 in group 2, 5.2 ± 1.2 in group 3, and 5.4 ± 1.6 in group 4; P = .0017), whereas GLSepi was impaired predominantly in group 2 (endocardial GLS and GLSepi were 15.0 ± 4.1% and 11.2 ± 3.3%, respectively, in group 1; 20.5 ± 2.8% and 16.2 ± 5.5% in group 2; 23.4 ± 3.3% and 18.2 ± 2.7% in group 3; and 24.6 ± 2.8% and 19.2 ± 1.9% in group 4; P < .0001 for all). GLSepi was able to detect subepicardial LGE in genetic variant carriers without overt ALVC with an area under curve of 0.84 (95% CI, 0.73-0.95). However, segmental epicardial and endocardial strain behaved similarly and showed comparable diagnostic values for segmental LGE detection (areas under the curve, 0.72; [95% CI, 0.69-0.76] and 0.73 [95% CI, 0.70-0.76], respectively, P = .40).

CONCLUSIONS

LSS alteration in ALVC progresses from the epicardium to the endocardium along with disease severity. Irrespective of LSS analysis, which did not provide incremental diagnostic value for the detection and localization of LGE, strain echocardiography was shown to be a potential surrogate marker of LGE, including in apparently healthy individuals with isolated LV fibrosis.

Prognostic impact of the findings of the genetic test in left dominant arrhythmogenic cardiomyopathy

Background

The diagnosis of left dominant arrhythmogenic cardiomyopathy (LDAC) is sometimes complex. The Padua group recently published a document with criteria to identify patients with LDAC, requiring a compatible genetic variant for diagnosis. Due to the gaps in the knowledge of the role of genetics in its pathogenesis, our objective is to describe the findings of the genetic test in patients with LDAC in our center and its prognostic impact.

Methods

Single-center prospective cohort study, in which we recruited 77 patients diagnosed with LDAC or biventricular arrhythmogenic cardiomyopathy according to the criteria of Sen-Chowdhry et al.

Results

We obtained a positive result in the genetic test in 53.2 %. The desmoplakin gene was the most affected (16.9 %). The mean value of left ventricular (LV) ejection fraction was 45.6 ± 13.1 %, with no significant differences in the severity of the dysfunction according to genetics (p = 0.187). Among the patients with positive genetics there was a greater number of segments in the LV affected by fibrosis (p = 0.043). Regarding fatty infiltration in the LV and number of affected segments, there were no significant differences between groups (p = 0.144). MACE was recorded in 23 patients (29.9 %). The positive result in the genetic test was not significantly associated with the occurrence of MACE (p = 0.902).

Conclusion

In our study, we did not find mutations responsible for the disease in practically half of the cases. Despite the existence of a high proportion of MACE during follow-up, there were no prognostic differences according to the result of the genetic test.

Imaging Features of Arrhythmogenic Cardiomyopathies

Arrhythmogenic cardiomyopathy (ACM) is a genetic disease characterized by replacement of ventricular myocardium with fibrofatty tissue, predisposing the patient to ventricular arrhythmias and/or sudden cardiac death. Most cases of ACM are associated with pathogenic variants in genes that encode desmosomal proteins, an important cell-to-cell adhesion complex present in both the heart and skin tissue. Although ACM was first described as a disease predominantly of the right ventricle, it is now acknowledged that it can also primarily involve the left ventricle or both ventricles. The original right-dominant phenotype is traditionally diagnosed using the 2010 task force criteria, a multifactorial algorithm divided into major and minor criteria consisting of structural criteria based on two-dimensional echocardiographic, cardiac MRI, or right ventricular angiographic findings; tissue characterization based on endomyocardial biopsy results; repolarization and depolarization abnormalities based on electrocardiographic findings; arrhythmic features; and family history. Shortfalls in the task force criteria due to the modern understanding of the disease have led to development of the Padua criteria, which include updated criteria for diagnosis of the right-dominant phenotype and new criteria for diagnosis of the left-predominant and biventricular phenotypes. In addition to incorporating cardiac MRI findings of ventricular dilatation, systolic dysfunction, and regional wall motion abnormalities, the new Padua criteria emphasize late gadolinium enhancement at cardiac MRI as a key feature in diagnosis and imaging-based tissue characterization. Conditions to consider in the differential diagnosis of the right-dominant phenotype include various other causes of right ventricular dilatation such as left-to-right shunts and variants of normal right ventricular anatomy that can be misinterpreted as abnormalities. The left-dominant phenotype can mimic myocarditis at imaging and clinical examination. Additional considerations for the differential diagnosis of ACM, particularly for the left-dominant phenotype, include sarcoidosis and dilated cardiomyopathy. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Arrhythmogenic Left Ventricular Cardiomyopathy: From Diagnosis to Risk Management

PURPOSE OF REVIEW

Left ventricular arrhythmogenic cardiomyopathy (ALVC) is a rare and poorly characterized cardiomyopathy that has recently been reclassified in the group of non-dilated left ventricular cardiomyopathies. This review aims to summarize the background, diagnosis, and sudden cardiac death risk in patients presenting this cardiomyopathy.

RECENT FINDINGS

Although there is currently a lack of data on this condition, arrhythmogenic left ventricular dysplasia can be considered a specific disease of the left ventricle (LV). We have collected the latest evidence about the management and the risks associated with this cardiomyopathy.

SUMMARY

Left ventricular arrhythmogenic cardiomyopathy is still poorly characterized. ALVC is characterized by fibrofatty replacement in the left ventricular myocardium, with variable phenotypic expression. Diagnosis is based on a multiparametric approach, including cardiac magnetic resonance (CMR) and genetic testing, and is important for sudden cardiac death (SCD) risk stratification and management. Recent guidelines have improved the management of left ventricular arrhythmogenic cardiomyopathy. Further studies are necessary to improve knowledge of this cardiomyopathy.

Multidisciplinary approach in cardiomyopathies: From genetics to advanced imaging

Cardiomyopathies are myocardial diseases characterized by mechanical and electrical dysfunction of the heart muscle which could lead to heart failure and life-threatening arrhythmias. Certainly, an accurate anamnesis, a meticulous physical examination, and an ECG are cornerstones in raising the diagnostic suspicion. However, cardiovascular imaging techniques are indispensable to diagnose a specific cardiomyopathy, to stratify the risk related to the disease and even to track the response to the therapy. Echocardiography is often the first exam that the patient undergoes, because of its non-invasiveness, wide availability, and cost-effectiveness. Cardiac magnetic resonance imaging allows to integrate and implement the information obtained with the echography. Furthermore, cardiomyopathies' genetic basis has been investigated over the years and the list of genetic mutations deemed potentially pathogenic is expected to grow further. The aim of this review is to show echocardiographic, cardiac magnetic resonance imaging, and genetic features of several cardiomyopathies: dilated cardiomyopathy (DMC), hypertrophic cardiomyopathy (HCM), arrhythmogenic cardiomyopathy (ACM), left ventricular noncompaction cardiomyopathy (LVNC), myocarditis, and takotsubo cardiomyopathy.

Phenotypic Expression and Clinical Outcomes in Patients With Arrhythmogenic Cardiomyopathies

BACKGROUND

In recent years, it has become evident that arrhythmogenic cardiomyopathy (ACM) displays a wide spectrum of ventricular involvement. Furthermore, the influence of various clinical phenotypes on the prognosis of the disease is currently being assessed.

OBJECTIVES

The purpose of this study was to evaluate the impact of phenotypic expression in ACM on patient outcomes.

METHODS

We conducted an analysis of 446 patients diagnosed with ACM. These patients were categorized into 3 groups based on their phenotype: arrhythmogenic right ventricular cardiomyopathy (ARVC) (right-dominant ACM), arrhythmogenic left ventricular cardiomyopathy (ALVC) (left-dominant ACM), and biventricular arrhythmogenic cardiomyopathy (BIV). We compared clinical, instrumental, and genetic findings among these groups and also evaluated their outcomes RESULTS: Overall, 44% of patients were diagnosed with ARVC, 23% with ALVC, and 33% with BIV forms. Subjects showing with ARVC and BIV phenotype had a significantly higher incidence of life-threatening ventricular arrhythmias compared with ALVC (P < 0.001). On the other hand, heart failure, heart transplantation, and death caused by cardiac causes were more frequent in individuals with BIV forms compared to those with ALVC and ARVC (P < 0.001). Finally, patients with an ALVC phenotype had a higher incidence of hot phases compared with those with ARVC and BIV forms (P = 0.013).

CONCLUSIONS

The comparison of ACM phenotypes demonstrated that patients with right ventricular involvement, such as ARVC and BIV forms, exhibit a higher incidence of life-threatening ventricular arrhythmias. Conversely, ACM forms characterized by left ventricular involvement, such as ALVC and BIV, show a higher incidence of heart failure, heart transplantation, and hot phases.

A case report of isolated arrhythmogenic left ventricular cardiomyopathy: phenotypes, diagnosis, and treatment

Background

Isolated arrhythmogenic left ventricular cardiomyopathy (IALVC) is a hereditary cardiomyopathy that is characterized by the replacement of left ventricular (LV) cardiomyocytes with fibrous and adipose tissue.

Case summary

A 55-year-old male patient presented with recurrent chest pain and palpitations characterized by episodes of monomorphic ventricular tachycardia and T-wave inversion. Coronary angiography was conducted to rule out myocardial ischaemia as the cause of chest pain. Echocardiography results revealed ventricular aneurysm formation at the apex of the left ventricle. Structural alterations of the cardiac magnetic resonance were consistent with the diagnosis of arrhythmogenic left ventricular cardiomyopathy with LV alterations without right ventricular involvement. Pathological staining of the lesion area further confirmed the diagnosis of IALVC. The TTN1 c.17617 C>A mutation in arrhythmogenic cardiomyopathy was identified using whole exome sequencing. His symptoms improved by the treatments including implantable cardioverter defibrillator (ICD) implantation, radiofrequency ablation, and ventricular aneurysm resection.

Discussion

The patient presented with IALVC with apical fibrofatty displacement and underwent surgical management, highlighting the importance of multimodal imaging, gene analysis, and histopathological findings for timely diagnosis, and emphasizing the benefits of life-saving therapy, including ICD implantation, radiofrequency ablation, and ventricular aneurysm resection. These findings contribute to a deeper understanding of the clinical presentation and outcome of IALVC.

Proposed diagnostic criteria for arrhythmogenic cardiomyopathy: European Task Force consensus report

Arrhythmogenic cardiomyopathy (ACM) is a heart muscle disease characterized by prominent "non-ischemic" myocardial scarring predisposing to ventricular electrical instability. Diagnostic criteria for the original phenotype, arrhythmogenic right ventricular cardiomyopathy (ARVC), were first proposed in 1994 and revised in 2010 by an international Task Force (TF). A 2019 International Expert report appraised these previous criteria, finding good accuracy for diagnosis of ARVC but a lack of sensitivity for identification of the expanding phenotypic disease spectrum, which includes left-sided variants, i.e., biventricular (ABVC) and arrhythmogenic left ventricular cardiomyopathy (ALVC). The ARVC phenotype together with these left-sided variants are now more appropriately named ACM. The lack of diagnostic criteria for the left ventricular (LV) phenotype has resulted in clinical under-recognition of ACM patients over the 4 decades since the disease discovery. In 2020, the "Padua criteria" were proposed for both right- and left-sided ACM phenotypes. The presently proposed criteria represent a refinement of the 2020 Padua criteria and have been developed by an expert European TF to improve the diagnosis of ACM with upgraded and internationally recognized criteria. The growing recognition of the diagnostic role of CMR has led to the incorporation of myocardial tissue characterization findings for detection of myocardial scar using the late‑gadolinium enhancement (LGE) technique to more fully characterize right, biventricular and left disease variants, whether genetic or acquired (phenocopies), and to exclude other "non-scarring" myocardial disease. The "ring-like' pattern of myocardial LGE/scar is now a recognized diagnostic hallmark of ALVC. Additional diagnostic criteria regarding LV depolarization and repolarization ECG abnormalities and ventricular arrhythmias of LV origin are also provided. These proposed upgrading of diagnostic criteria represents a working framework to improve management of ACM patients.

Arrhythmogenic Cardiomyopathy: Definition, Classification and Arrhythmic Risk Stratification

Arrhythmogenic cardiomyopathy (ACM) is a heart disease characterized by a fibrotic replacement of myocardial tissue and a consequent predisposition to ventricular arrhythmic events, especially in the young. Post-mortem studies and the subsequent diffusion of cardiac MRI have shown that left ventricular involvement in arrhythmogenic cardiomyopathy is common and often develops early. Regarding the arrhythmic risk stratification, the current scores underestimate the arrhythmic risk of patients with arrhythmogenic cardiomyopathy with left involvement. Indeed, the data on arrhythmic risk stratification in this group of patients are contradictory and not exhaustive, with the consequence of not correctly identifying patients at a high arrhythmic risk who deserve protection from arrhythmic death. We propose a literature review on arrhythmic risk stratification in patients with ACM and left involvement to identify the main features associated with an increased arrhythmic risk in this group of patients.

Cardiac magnetic resonance assessment of athletic myocardial fibrosis; Benign bystander or malignant marker?

The benefits of exercise are irrefutable with a well-established dose-dependent relationship between exercise intensity and reduction in cardiovascular disease. Differentiating the physiological adaptation to exercise, termed the "athlete's heart" from cardiomyopathies, has been advanced by the advent of more sophisticated imaging modalities such as cardiac magnetic resonance imaging (CMR). Myocardial fibrosis on CMR is a mutual finding amongst seemingly healthy endurance athletes and individuals with cardiomyopathy. As a substrate for arrhythmias, fibrosis is traditionally associated with increased cardiovascular risk. In this article, we discuss the aetiologies, distribution and potential implications of myocardial fibrosis in athletes.

Cardiac MRI and Clinical Outcomes in TMEM43 Arrhythmogenic Cardiomyopathy

Arrhythmogenic cardiomyopathy is an inherited cardiomyopathy that can involve both ventricles. Several genes have been identified as pathogenic in arrhythmogenic cardiomyopathy, including TMEM43. However, there are limited data on cardiac MRI findings in patients with TMEM43 variants to date. In this case series, cardiac MRI findings and clinical outcomes are described in 14 patients with TMEM43 variants, including eight (57%) with the pathogenic p.Ser358Leu variant (six female patients; mean age, 33 years ± 15 [SD]) and six (43%) with a TMEM43 variant of unknown significance (three female patients; mean age, 38 years ± 11). MRI findings demonstrated left ventricular systolic dysfunction in eight (57%) patients and right ventricular dysfunction in four (29%) patients. Among the nine patients with late gadolinium enhancement imaging, left ventricular late gadolinium enhancement was present in seven (78%; all subepicardial) patients. In summary, TMEM43 variants are associated with high prevalence of subepicardial late gadolinium enhancement and left ventricular dysfunction. Keywords: Arrhythmogenic Cardiomyopathy, Arrhythmogenic Right Ventricular Cardiomyopathy, TMEM43, Cardiac MRI, Genetic Variants Supplemental material is available for this article.

Utilities and Limitations of Cardiac Magnetic Resonance Imaging in Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) is one of the most common types of non-ischemic cardiomyopathy. DCM is characterized by left ventricle (LV) dilatation and systolic dysfunction without coronary artery disease or abnormal loading conditions. DCM is not a single disease entity and has a complex historical background of revisions and updates to its definition because of its diverse etiology and clinical manifestations. In cases of LV dilatation and dysfunction, conditions with phenotypic overlap should be excluded before establishing a DCM diagnosis. The differential diagnoses of DCM include ischemic cardiomyopathy, valvular heart disease, burned-out hypertrophic cardiomyopathy, arrhythmogenic cardiomyopathy, and non-compaction. Cardiac magnetic resonance (CMR) imaging is helpful for evaluating DCM because it provides precise measurements of cardiac size, function, mass, and tissue characterization. Comprehensive analyses using various sequences, including cine imaging, late gadolinium enhancement imaging, and T1 and T2 mapping, may help establish differential diagnoses, etiological work-up, disease stratification, prognostic determination, and follow-up procedures in patients with DCM phenotypes. This article aimed to review the utilities and limitations of CMR in the diagnosis and assessment of DCM.

Arrhythmogenic left ventricular cardiomyopathy caused by a novel likely pathogenic DSP mutation, p.K1165Rfs*8, in a family with sudden cardiac death

OBJECTIVE

We conducted an investigation into the clinical and molecular characteristics of Arrhythmogenic left ventricular cardiomyopathy (ALVC) caused by a novel likely pathogenic mutation in an Iranian pedigree with sudden cardiac death (SCD).

BACKGROUND

ALVC is a genetically inherited myocardial disease characterized by the substitution of fibro-fatty tissue in the left ventricular myocardium, predominantly inherited in an autosomal dominant pattern and is commonly associated with genes involved in encoding desmosomal proteins, specifically Desmoplakin (DSP).

METHODS

The patient and available family members underwent a comprehensive clinical assessment, including Cardiac magnetic resonance (CMR) imaging, along with Whole-exome sequencing (WES). The identified variant was confirmed and segregated by Polymerase chain reaction (PCR) and Sanger sequencing in the family members.

RESULTS

A novel likely pathogenic heterozygous variant, DSP (NM_004415.4), c.3492_3498del, p.K1165Rfs*8 was discovered in the proband. This variant is likely to be the primary reason for ALVC in this specific family. This variant was confirmed by Sanger sequencing and segregated in other affected members of the family.

CONCLUSION

We identified a novel likely pathogenic variant in the DSP gene, which has been identified as the cause of ALVC in an Iranian family. Our investigation underscores the importance of genetic testing, specifically WES, for individuals suspected of ALVC and have a family history of SCD.

Recognizing a "Hot Phase" of An Arrhythmogenic Left Ventricular Cardiomyopathy: A Case Report

A 35-year-old male, with a medical history of acute myocarditis, presented with palpitations. Further investigation revealed non-sustained ventricular tachycardia and a slightly reduced left ventricular systolic function. Cardiac magnetic resonance showed extended late gadolinium enhancement of the left ventricle and fat infiltration. Genetic testing was positive for a pathogenic desmoplakin mutation, fulfilling the criteria of arrhythmogenic left ventricular cardiomyopathy. In conclusion, the authors described a case of a mimicked acute myocarditis at a young age in a patient with an arrhythmogenic left ventricular cardiomyopathy. Therefore, the genetic study is essential for both diagnosis and management.

Arrhythmogenic Cardiomyopathy: Evolving Diagnostic Criteria and Insight from Cardiac Magnetic Resonance Imaging

Arrhythmogenic cardiomyopathy (ACM) is an umbrella term encompassing a wide variety of overlapping hereditary and nonhereditary disorders that can result in malignant ventricular arrhythmias and sudden cardiac death. Cardiac MRI plays a critical role in accurate diagnosis of various ACM entities and is increasingly showing promise in risk stratification that can further guide management particularly in decisions regarding use of implantable cardioverter defibrillator. Genotyping plays an important role in cascade testing but challenges remain due to incomplete penetrance and wide phenotypic variability of ACM as well as the presence of gene-elusive cases.

Isolated JUP plakoglobin gene mutation with left ventricular fibrosis in familial arrhythmogenic right ventricular cardiomyopathy

INTRODUCTION

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a rare inherited disorder usually affecting the right ventricle (RV), characterized by fibro-fatty tissue replacement of the healthy ventricular myocardium. It often predisposes young patients to ventricular tachycardia, heart failure, and/or sudden cardiac death. However, recent studies have suggested predominantly left ventricle (LV) involvement with variable and/or atypical manifestations. Cardiac magnetic resonance (CMR) imaging has emerged as the noninvasive gold standard for the diagnosis of ARVC.

CASE SUMMARY

A 21-year-old athletic male with a family history of unknown ventricular arrhythmias, presented with near syncope, chest pain, and exertional palpitations. He had an initial work-up that was grossly unremarkable including an electrocardiogram (ECG), echocardiogram and a CMR study. Six months later, he presented again with recurrent symptoms of presyncope during exercise and his ECG demonstrated new findings of a terminal activation delay in his precordial leads. He had markedly elevated cardiac biomarkers, (troponin I > 100 ng/dl, normal value < 0.04 ng/dl) and demonstrated ventricular tachycardia with a right bundle branch morphology. An endomyocardial biopsy did not reveal any pathology. A follow-up CMR demonstrated the new development and prominent left ventricular epicardial scar in the lateral wall. The patient underwent familial genetic testing, which confirmed the presence of an isolated junction plakoglobin (JUP) gene mutation and showed multiple genes consistent with ARVC in his mother. Thus, he manifested a partial transmission of only one abnormal gene for ARVC and exhibited a markedly different expression in his disease without evidence of typical right-sided heart pathology. A third CMR study was performed, which showed partial improvement in myocardial fibrosis after exercise cessation.

CONCLUSION

We present a case of a young athletic male with a newly diagnosed isolated JUP gene mutation and a genetically diagnosed family history of ARVC. During his course, he demonstrated the progression of new, atypical, left ventricular fibrosis. This case demonstrates a complex interplay between genetic penetrance, phenotypical heterogeneity, and lifestyle factors such as exercise in disease progression and provides insight into the natural course of an isolated JUP mutation. Although rare, clinicians should have a high threshold for the clinical suspicion of ARVC or variants of this disorder even in the absence of classic right-sided pathologies.

Left-dominant arrhythmogenic cardiomyopathy due to desmoplakin mutation: a case report

The case of a 49-year-old man with acute onset of heart failure is presented. The initial work-up showed a dilated cardiomyopathy with severely reduced left ventricular ejection fraction. In the differential diagnostic process, hypertensive, ischaemic, and valvular aetiologies were discarded. Subsequently, a cardiac magnetic resonance revealed global hypokinesis and inferior and anterior subepicardial fibrosis. Once differential diagnoses of subepicardial fibrosis (myocarditis, sarcoidosis, and Chagas disease) were discarded, a genetic panel was performed, resulting in a heterozygous mutation of desmoplakin (DSP) gene c.6697_6698del. A left-dominant DSP arrhythmogenic cardiomyopathy mutation was diagnosed. Structural myocardial abnormalities and ventricular arrhythmias characterize arrhythmogenic cardiomyopathy. Up to 50% of cases are associated with mutations in DSP genes (JUP, DSP, and PKP2). DSP is the fundamental component of the desmosome structure and provides structural support through intercellular adhesion. Therefore, when frequent differential diagnoses are discarded, genetic studies for dilated cardiomyopathy and DSP mutation should be considered.

Biventricular arrhythmogenic cardiomyopathy diagnosed in a young patient: A case report with literature review

Arrhythmogenic cardiomyopathy is a genetic heart muscle disease that typically affects the right ventricle. However, 2 other phenotypes affecting the left ventricle were recently discovered. Here, we report the case of an 18-year-old patient with biventricular arrhythmogenic cardiomyopathy, highlighting the challenges encountered in establishing this diagnosis. Diagnostic criteria for the left-sided phenotypic variants of arrhythmogenic cardiomyopathy were only introduced in 2020 by an international expert consensus document, known as the "Padua criteria," they are divided in 6 categories with an emphasis on morpho-functional ventricular abnormalities and structural myocardial tissue alterations to diagnose biventricular arrhythmogenic cardiomyopathy.

Arrhythmogenic Left Ventricular Cardiomyopathy: A Successful Case of Extracorporeal Cardiopulmonary Resuscitation

A 24-year-old man suffered a witnessed cardiac arrest after a padel game. Basic life support was immediately provided. The pre-hospital emergency services team continued the resuscitation efforts, and the patient was accepted for extracorporeal cardiopulmonary resuscitation. The return of spontaneous circulation was achieved in 45 minutes. The initial assessment revealed a ST-segment elevation in leads V4-V6 and a dilated left ventricle with severe systolic dysfunction. Coronary angiography was normal. An improvement in left ventricular systolic function was observed and extracorporeal cardiac support was discontinued after 48 hours. Cardiovascular magnetic resonance imaging demonstrated hypokinesia and subepicardial fatty infiltration of the left ventricle lateral wall. Genetic testing detected a variant of uncertain significance in the ANK2 gene. The diagnosis of arrhythmogenic left ventricular myocardiopathy did not fulfill all the current diagnostic criteria, but it is a very likely diagnosis. An implantable cardioverter-defibrillator was placed. The patient was discharged without physical or cognitive impairment.

Cardiac Emergency in the Athlete

Cardiac-related deaths are the leading nontraumatic cause of death in the young athlete. Although there are multiple causes for cardiac arrest in athletes, sideline evaluation and management does not vary. Recognition, immediate high-quality chest compressions, and time to defibrillation are the greatest factors affecting survival. This article reviews the approach to the collapsed athlete, causes for select cardiac emergencies in athletes, preparedness for cardiac emergencies, and return to play considerations and recommendations.

The pivotal role of ECG in cardiomyopathies

Cardiomyopathies are a heterogeneous group of pathologies characterized by structural and functional alterations of the heart. Recent technological advances in cardiovascular imaging offer an opportunity for deep phenotypic and etiological definition. Electrocardiogram (ECG) is the first-line diagnostic tool in the evaluation of both asymptomatic and symptomatic individuals. Some electrocardiographic signs are pathognomonic or fall within validated diagnostic criteria of individual cardiomyopathy such as the inverted T waves in right precordial leads (V1-V3) or beyond in individuals with complete pubertal development in the absence of complete right bundle branch block for the diagnosis of arrhythmogenic cardiomyopathy of the right ventricle (ARVC) or the presence of low voltages typically seen in more than 60% of patients with amyloidosis. Most other electrocardiographic findings such as the presence of depolarization changes including QRS fragmentation, the presence of epsilon wave, the presence of reduced or increased voltages as well as alterations in the repolarization phase including the negative T waves in the lateral leads, or the profound inversion of the T waves or downsloping of the ST tract are more non-specific signs which can however raise the clinical suspicion of cardiomyopathy in order to initiate a diagnostic procedure especially using imaging techniques for diagnostic confirmation. Such electrocardiographic alterations not only have a counterpart in imaging investigations such as evidence of late gadolinium enhancement on magnetic resonance imaging, but may also have an important prognostic value once a definite diagnosis has been made. In addition, the presence of electrical stimulus conduction disturbances or advanced atrioventricular blocks that can be seen especially in conditions such as cardiac amyloidosis or sarcoidosis, or the presence of left bundle branch block or posterior fascicular block in dilated or arrhythmogenic left ventricular cardiomyopathies are recognized as a possible expression of advanced pathology. Similarly, the presence of ventricular arrhythmias with typical patterns such as non-sustained or sustained ventricular tachycardia of LBBB morphology in ARVC or non-sustained or sustained ventricular tachycardia with an RBBB morphology (excluding the "fascicular pattern") in arrhythmogenic left ventricle cardiomyopathy could have a significant impact on the course of each disease. It is therefore clear that a learned and careful interpretation of ECG features can raise suspicion of the presence of a cardiomyopathy, identify diagnostic "red flags" useful for orienting the diagnosis toward specific forms, and provide useful tools for risk stratification. The purpose of this review is to emphasize the important role of the ECG in the diagnostic workup, describing the main ECG findings of different cardiomyopathies.

Arrhythmogenic Cardiomyopathy and Athletes - A Dangerous Relationship

Arrhythmogenic cardiomyopathy (ACM) is a disease characterized by a progressive replacement of myocardium by fibro-adipose material, predisposing to ventricular arrhythmias (VA) and sudden cardiac death (SCD). Its prevalence is estimated at 1:2000 to 1:5000, with a higher incidence in males, and clinical onset is usually between the 2nd and 4th decade of life. The prevalence of ACM in SCD victims is relatively high, making it one of the most common etiologies in young patients with SCD, especially if they are athletes. Cardiac events occur more frequently in individuals with ACM who participate in competitive sports and/or high-intensity training. In effect, exercise activity can worsen RV function in cases of hereditary ACM. Estimating the incidence of SCD caused by ACM in athletes remains challenging, being reported frequency ranging from 3-20%. Here, we review the potential implications of exercising on the clinical course of the classical genetic form of ACM, as well as the diagnostic tools, risk stratification, and the different therapeutic tools available for managing ACM.

Scarring/arrhythmogenic cardiomyopathy

The designation of 'arrhythmogenic cardiomyopathy' reflects the evolving concept of a heart muscle disease affecting not only the right ventricle (ARVC) but also the left ventricle (LV), with phenotypic variants characterized by a biventricular (BIV) or predominant LV involvement (ALVC). Herein, we use the term 'scarring/arrhythmogenic cardiomyopathy (S/ACM)' to emphasize that the disease phenotype is distinctively characterized by loss of ventricular myocardium due to myocyte death with subsequent fibrous or fibro-fatty scar tissue replacement. The myocardial scarring predisposes to potentially lethal ventricular arrhythmias and underlies the impairment of systolic ventricular function. S/ACM is an 'umbrella term' which includes a variety of conditions, either genetic or acquired (mostly post-inflammatory), sharing the typical 'scarring' phenotypic features of the disease. Differential diagnoses include 'non-scarring' heart diseases leading to either RV dilatation from left-to-right shunt or LV dilatation/dysfunction from a dilated cardiomyopathy. The development of 2020 upgraded criteria ('Padua criteria') for diagnosis of S/ACM reflected the evolving clinical experience with the expanding spectrum of S/ACM phenotypes and the advances in cardiac magnetic resonance (CMR) imaging. The Padua criteria aimed to improve the diagnosis of S/ACM by incorporation of CMR myocardial tissue characterization findings. Risk stratification of S/ACM patients is mostly based on arrhythmic burden and ventricular dysfunction severity, although other ECG or imaging parameters may have a role. Medical therapy is crucial for treatment of ventricular arrhythmias and heart failure. Implantable cardioverter defibrillator (ICD) is the only proven life-saving treatment, despite its significant morbidity because of device-related complications and inappropriate shocks. Selection of patients who can benefit the most from ICD therapy is one of the most challenging issues in clinical practice.

Pragmatic electrocardiogram tracings in non-ischaemic dilated cardiomyopathy: diagnostic and prognostic role

Dilated cardiomyopathy (DCM) is a primitive heart muscle disease characterized by a great heterogeneous aetiology and prognostic outcome. Dilated cardiomyopathy is an umbrella term encompassing different aetiologies that might require specific treatments. It principally affects young and male adults, with high-risk arrhythmic competitive risk. Unfortunately, the prevention of major ventricular arrhythmic events remains a clinical challenge. In the era of advanced multimodality imaging and widely available genetic testing, electrocardiogram (ECG) continues to represent a reliable diagnostic tool, for specific work up of every single patient. However, approaching DCM patients, only a cardiomyopathy-oriented reading makes the role of ECG central in the management of DCM, both for diagnosis, prognosis, and therapeutic management. In this paper, we present four ECGs of four different DCM patients, in order to guide a cardiomyopathy-oriented ECG reading, emphasizing its impact in an early, cost-effective, and personalized diagnostic and prognostic work up in this specific setting.

Desmoplakin Cardiomyopathy: Comprehensive Review of an Increasingly Recognized Entity

Desmoplakin (DSP) is a desmosomal protein that plays an essential role for cell-to-cell adhesion within the cardiomyocytes. The first association between DSP genetic variants and the presence of a myocardial disease referred to patients with Carvajal syndrome. Since then, several reports have linked the DSP gene to familial forms of arrhythmogenic (ACM) and dilated cardiomyopathies. Left-dominant ACM is the most common phenotype in individuals carrying DSP variants. More recently, a new entity—“Desmoplakin cardiomyopathy”—was described as a distinct form of cardiomyopathy characterized by frequent left ventricular involvement with extensive fibrosis, high arrhythmic risk, and episodes of acute myocardial injury. The purpose of this review was to summarize the available evidence on DSP cardiomyopathy and to identify existing gaps in knowledge that need clarification from upcoming research.

Genetically determined cardiomyopathies at autopsy: the pivotal role of the pathologist in establishing the diagnosis and guiding family screening

Cardiomyopathies (CMP) comprise a heterogenous group of diseases affecting primarily the myocardium, either genetic and/or acquired in origin. While many classification systems have been proposed in the clinical setting, there is no internationally agreed pathological consensus concerning the diagnostic approach to inherited CMP at autopsy. A document on autopsy diagnosis of CMP is needed because the complexity of the pathologic backgrounds requires proper insight and expertise. In cases presenting with cardiac hypertrophy and/or dilatation/scarring with normal coronary arteries, a suspicion of inherited CMP must be considered, and a histological examination is essential. Establishing the actual cause of the disease may require a number of tissue-based and/or fluid-based investigations, be it histological, ultrastructural, or molecular. A history of illicit drug use must be looked for. Sudden death is frequently the first manifestation of disease in case of CMP, especially in the young. Also, during routine clinical or forensic autopsies, a suspicion of CMP may arise based on clinical data or pathological findings at autopsy. It is thus a challenge to make a diagnosis of a CMP at autopsy. The pathology report should provide the relevant data and a cardiac diagnosis which can help the family in furthering investigations, including genetic testing in case of genetic forms of CMP. With the explosion in molecular testing and the concept of the molecular autopsy, the pathologist should use strict criteria in the diagnosis of CMP, and helpful for clinical geneticists and cardiologists who advise the family as to the possibility of a genetic disease.

Opportunities and drawbacks of the subcutaneous defibrillator across different clinical settings

INTRODUCTION

The subcutaneous implantable cardioverter-defibrillator (S-ICD) is an established therapy for the prevention of sudden cardiac death (SCD) and an alternative to a transvenous implantable cardioverter-defibrillator system in selected patients. Beyond randomized clinical trials, many observational studies have described the clinical performance of S-ICD across different subgroups of patients.

AREAS COVERED

Our review aimed to describe the opportunities and drawbacks of the S-ICD, focusing on their use in special populations and across different clinical settings.

EXPERT OPINION

The choice to implant S-ICD should be based on the patient's tailored approach, which takes into account the adequate S-ICD screening at rest or during stress, the infective risk, the ventricular arrhythmia susceptibility, the progressive nature of the underlying disease, the work or sports activity, and the risk of lead-related complications.

Role of cardiac magnetic resonance in the differential diagnosis between arrhythmogenic cardiomyopathy with left ventricular involvement and previous infectious myocarditis

AIMS

Arrhythmogenic cardiomyopathy with left ventricular involvement (ACM-LV), particularly in case of isolated left ventricular involvement (i.e. left dominant arrhythmogenic cardiomyopathy, LDAC) and previous infectious myocarditis (pIM) may have overlapping clinical and cardiac magnetic resonance (CMR) features. To date, there are no validated CMR criteria for the differential diagnosis between these conditions. The present study aimed to identify CMR characteristics to distinguish ACM-LV from pIM.

METHODS AND RESULTS

This observational, retrospective, single-centre study included 30 pIM patients and 30 ACM-LV patients. In ACM-LV patients CMR was performed at diagnosis; in patients with pIM, CMR was performed six months after acute infection. CMR analysis included quantitative assessment of left ventricle (LV) volumes, systolic function and wall thicknesses, qualitative and quantitative assessment of late gadolinium enhancement (LGE) sequences. Compared with pIM, ACM-LV patients showed slightly larger LV volumes, more frequent regional wall motion anomalies and reduced wall thicknesses. ACM-LV patients had higher amounts of LV LGE and extension. Notably, the LDAC subgroup had the highest amount of LV LGE. LV LGE amount > 15 g and a LV LGE percentage > 30% of LV mass discriminated ACM-LV from pIM with a 100% specificity. LGE segmental distribution was superimposable among the groups, except for septal segments that were more frequently involved in ACM-LV and LDAC patients.

CONCLUSIONS

A great extension of LV LGE (a cut-off of LGE >15 g and a percentage above 30% of LV LGE in relation to total myocardial mass) discriminates ACM-LV from pIM with extremely high specificity.

Multimodality Imaging in Arrhythmogenic Left Ventricular Cardiomyopathy

The term arrhythmogenic cardiomyopathy (ACM) describes a large spectrum of myocardial diseases characterized by progressive fibrotic or fibrofatty replacement, which gives the substrate for the occurrence of ventricular tachyarrhythmias and the development of ventricular dysfunction. This condition may exclusively affect the left ventricle, leading to the introduction of the term arrhythmogenic left ventricular cardiomyopathy (ALVC). The clinical features of ALVC are progressive fibrotic replacement with the absence or mild dilation of the LV and the occurrence of ventricular arrhythmias within the left ventricle. In 2019, the diagnostic criteria for the diagnosis of ALVC, based on family history and clinical, electrocardiographic, and imaging features, have been proposed. However, since the significant clinical and imaging overlap with other cardiac diseases, genetic testing with the demonstration of a pathogenic variant in an ACM-related gene is required for diagnostic confirmation. In ALVC, the multimodality imaging approach comprises different imaging techniques, such as echocardiography, cardiac magnetic resonance, and cardiac nuclear imaging. It provides essential information for the diagnosis, differential diagnosis, sudden cardiac death risk stratification, and management purposes. This review aims to elucidate the current role of the different multimodality imaging techniques in patients with ALVC.

Clinical Features, Genetic Findings, and Risk Stratification in Arrhythmogenic Right Ventricular Cardiomyopathy: Data From a Brazilian Cohort

BACKGROUND

Arrhythmogenic right ventricular cardiomyopathy (ARVC), a rare inherited disease, causes ventricular tachycardia, sudden cardiac death, and heart failure (HF). We investigated ARVC clinical features, genetic findings, natural history, and the occurrence of life-threatening arrhythmic events (LTAEs), HF death, or heart transplantation (HF-death/HTx) to identify risk factors.

METHODS

The clinical course of 111 consecutive patients with definite ARVC, predictors of LTAE, HF-death/HTx, and combined events were analyzed in the entire cohort and in a subgroup of 40 patients without sustained ventricular arrhythmia before diagnosis.

RESULTS

The 5-year cumulative probability of LTAE was 30% and HF-death/HTx was 10%. Predictors of HF-death/HTx were reduced right ventricle ejection fraction (HR: 0.93; P=0.010), HF symptoms (HR: 4.37; P=0.010), epsilon wave (HR: 4.99; P=0.015), and number of leads with low QRS voltage (HR: 1.28; P=0.001). Each additional lead with low QRS voltage increased the risk of HF-death/HTx by 28%. Predictors of LTAE were prior syncope (HR: 1.81; P=0.040), number of leads with T wave inversion (HR: 1.17; P=0.039), low QRS voltage (HR: 1.12; P=0.021), younger age (HR: 0.97; P=0.006), and prior ventricular arrhythmia/ventricular fibrillation (HR: 2.45; P=0.012). Each additional lead with low QRS voltage increased the risk of LTAE by 17%. In patients without ventricular arrhythmia before clinical diagnosis of ARVC, the number of leads with low QRS voltage (HR: 1.68; P=0.023) was independently associated with HF-death/HTx.

CONCLUSIONS

Our study demonstrated the characteristics of a specific cohort with a high prevalence of arrhythmic burden at presentation, male predominance, younger age and HF severe outcomes. Our main results suggest that the presence and extension of low QRS voltage can be a risk predictor for HF-death/HTx in ARVC patients, regardless of the arrhythmic risk. This study can contribute to the global ARVC risk stratification, adding new insights to the international current scientific knowledge.

DSP-Related Cardiomyopathy as a Distinct Clinical Entity? Emerging Evidence from an Italian Cohort

Variants in desmoplakin gene (DSP MIM *125647) have been usually associated with Arrhythmogenic Cardiomyopathy (ACM), or Dilated Cardiomyopathy (DCM) inherited in an autosomal dominant manner. A cohort of 18 probands, characterized as heterozygotes for DSP variants by a target Next Generation Sequencing (NGS) cardiomyopathy panel, was analyzed. Cardiological, genetic data, and imaging features were retrospectively collected. A total of 16 DSP heterozygous pathogenic or likely pathogenic variants were identified, 75% (n = 12) truncating variants, n = 2 missense variants, n = 1 splicing variant, and n = 1 duplication variant. The mean age at diagnosis was 40.61 years (IQR 31-47.25), 61% of patients being asymptomatic (n = 11, New York Heart Association (NYHA) class I) and 39% mildly symptomatic (n = 7, NYHA class II). Notably, 39% of patients (n = 7) presented with a clinical history of presumed myocarditis episodes, characterized by chest pain, myocardial enzyme release, 12-lead electrocardiogram abnormalities with normal coronary arteries, which were recurrent in 57% of cases (n = 4). About half of the patients (55%, n = 10) presented with a varied degree of left ventricular enlargement (LVE), four showing biventricular involvement. Eleven patients (61%) underwent implantable cardioverter defibrillator (ICD) implantation, with a mean age of 46.81 years (IQR 36.00-64.00). Cardiac magnetic resonance imaging (CMRI) identified in all 18 patients a delayed enhancement (DE) area consistent with left ventricular (LV) myocardial fibrosis, with a larger localization and extent in patients presenting with recurrent episodes of myocardial injury. These clinical and genetic data confirm that DSP-related cardiomyopathy may represent a distinct clinical entity characterized by a high arrhythmic burden, variable degrees of LVE, Late Gadolinium Enhancement (LGE) with subepicardial distribution and episodes of myocarditis-like picture.

Varied Presentation of Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy (ARVD/C): A Case Series

Arrhythmogenic right ventricular dysplasia (ARVD) is a genetically predisposed form of cardiomyopathy that mainly affects young individuals resulting in fatal ventricular arrhythmias leading to sudden cardiac death. ARVD has 50% of cases that involve both the right ventricle (RV) and left ventricle (LV), but only a small number of cases involve an isolated left ventricle. In this case series, five patients (four males and one female) with a diagnosis of ARVD presented to our center with varied clinical presentations across a wide range of age groups. The MRI of all five cases showed dilated right atrium (RA)/RV with right ventricular free wall dyskinesia. Two-dimensional (2D) MRI showed aneurysmal outpouching with diffuse free wall enhancement. Automated implantable cardioverter defibrillator (AICD) was implanted uneventfully in all five patients, and the patients were discharged with oral medications such as low-dose diuretics, beta-blockers, spironolactone, angiotensin-converting enzymes (ACE) inhibitors, amiodarone, and anxiolytics. Until now, the patients were doing well on follow-up visits. The therapeutic management of patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) has evolved over the years and continues to be an important challenge. To further improve risk stratification and treatment of patients, more information is needed on natural history, long-term prognosis, and risk assessment. Special attention should be focused on the identification of patients who would benefit from implantable cardioverter-defibrillator (ICD) implantation in comparison to pharmacological and other nonpharmacological approaches.

Pregnancy in Women with Arrhythmogenic Left Ventricular Cardiomyopathy

BACKGROUND

In the last few years, a phenotypic variant of arrhythmogenic cardiomyopathy (ACM) labeled arrhythmogenic left ventricular cardiomyopathy (ALVC) has been defined and researched. This type of cardiomyopathy is characterized by a predominant left ventricular (LV) involvement with no or minor right ventricular (RV) abnormalities. Data on the specific risk and management of pregnancy in women affected by ALVC are, thus far, not available. We have sought to characterize pregnancy course and outcomes in women affected by ALVC through the evaluation of a series of childbearing patients.

METHODS

A series of consecutive female ALVC patients were analyzed in a cross-sectional, retrospective study. Study protocol included 12-lead ECG assessments, 24-h Holter ECG evaluations, 2D-echocardiogram tests, cardiac magnetic resonance assessments, and genetic analysis. Furthermore, the long-term disease course of childbearing patients was compared with a group of nulliparous ALVC women.

RESULTS

A total of 35 patients (mean age 45 ± 9 years, 51% probands) were analyzed. Sixteen women (46%) reported a pregnancy, for a total of 27 singleton viable pregnancies (mean age at first childbirth 30 ± 9 years). Before pregnancy, all patients were in the NYHA class I and none of the patients reported a previous heart failure (HF) episode. No significant differences were found between childbearing and nulliparous women regarding ECG features, LV dimensions, function, and extent of late enhancement. Overall, 7 patients (20%, 4 belonging to the childbearing group) experienced a sustained ventricular tachycardia and 2 (6%)-one for each group-showed heart failure (HF) episodes. The analysis of arrhythmia-free survival patients did not show significant differences between childbearing and nulliparous women.

CONCLUSIONS

In a cohort of ALVC patients without previous episodes of HF, pregnancy was well tolerated, with no significant influence on disease progression and degree of electrical instability. Further studies on a larger cohort of women with different degrees of disease extent and genetic background are needed in order to achieve a more comprehensive knowledge regarding the outcome of pregnancy in ALVC patients.

Non Coding RNAs as Regulators of Wnt/β-Catenin and Hippo Pathways in Arrhythmogenic Cardiomyopathy

Arrhythmogenic cardiomyopathy (ACM) is an inherited cardiomyopathy histologically characterized by the replacement of myocardium by fibrofatty infiltration, cardiomyocyte loss, and inflammation. ACM has been defined as a desmosomal disease because most of the mutations causing the disease are located in genes encoding desmosomal proteins. Interestingly, the instable structures of these intercellular junctions in this disease are closely related to a perturbed Wnt/β-catenin pathway. Imbalance in the Wnt/β-catenin signaling and also in the crosslinked Hippo pathway leads to the transcription of proadipogenic and profibrotic genes. Aiming to shed light on the mechanisms by which Wnt/β-catenin and Hippo pathways modulate the progression of the pathological ACM phenotype, the study of non-coding RNAs (ncRNAs) has emerged as a potential source of actionable targets. ncRNAs comprise a wide range of RNA species (short, large, linear, circular) which are able to finely tune gene expression and determine the final phenotype. Some share recognition sites, thus referred to as competing endogenous RNAs (ceRNAs), and ensure a coordinating action. Recent cancer research studies regarding the key role of ceRNAs in Wnt/β-catenin and Hippo pathways modulation pave the way to better understanding the molecular mechanisms underlying ACM.

Arrhythmogenic Cardiomyopathy: A Review of a Rare Case of Biventricular Phenotype

Arrhythmogenic cardiomyopathy is a rare hereditary structural heart disease, with various phenotypes, which mostly affects the right ventricle of the heart, resulting in fibrofatty replacement of the heart muscles and a proclivity to create spontaneous malignant cardiac arrhythmias that may lead to sudden death. Most previous reports were noted on young people. We report a case of its biventricular phenotype in a 61-year-old heavy truck driver who has a current medical history of diabetes mellitus and smoking and was incidentally diagnosed based on the Padua criteria after presenting to the hospital with complaints of lightheadedness and syncope. He eventually had an implantable cardioverter defibrillator, hence preventing death. We were able to correctly diagnose the case and prevent sudden cardiac death by instituting the necessary management.

Myocarditis-like Episodes in Patients with Arrhythmogenic Cardiomyopathy: A Systematic Review on the So-Called Hot-Phase of the Disease

Arrhythmogenic cardiomyopathy (ACM) is a genetically determined myocardial disease, characterized by myocytes necrosis with fibrofatty substitution and ventricular arrhythmias that can even lead to sudden cardiac death. The presence of inflammatory cell infiltrates in endomyocardial biopsies or in autoptic specimens of ACM patients has been reported, suggesting a possible role of inflammation in the pathophysiology of the disease. Furthermore, chest pain episodes accompanied by electrocardiographic changes and troponin release have been observed and defined as the “hot-phase” phenomenon. The aim of this critical systematic review was to assess the clinical features of ACM patients presenting with “hot-phase” episodes. According to PRISMA guidelines, a search was run in the PubMed, Scopus and Web of Science electronic databases using the following keywords: “arrhythmogenic cardiomyopathy”; “myocarditis” or “arrhythmogenic cardiomyopathy”; “troponin” or “arrhythmogenic cardiomyopathy”; and “hot-phase”. A total of 1433 titles were retrieved, of which 65 studies were potentially relevant to the topic. Through the application of inclusion and exclusion criteria, 9 papers reporting 103 ACM patients who had experienced hot-phase episodes were selected for this review. Age at time of episodes was available in 76% of cases, with the mean age reported being 26 years ± 14 years (min 2–max 71 years). Overall, 86% of patients showed left ventricular epicardial LGE. At the time of hot-phase episodes, 49% received a diagnosis of ACM (Arrhythmogenic left ventricular cardiomyopathy in the majority of cases), 19% of dilated cardiomyopathy and 26% of acute myocarditis. At the genetic study, Desmoplakin (DSP) was the more represented disease-gene (69%), followed by Plakophillin-2 (9%) and Desmoglein-2 (6%). In conclusion, ACM patients showing hot-phase episodes are usually young, and DSP is the most common disease gene, accounting for 69% of cases. Currently, the role of “hot-phase” episodes in disease progression and arrhythmic risk stratification remains to be clarified.

Catheter Ablation in Arrhythmic Cardiac Diseases: Endocardial and Epicardial Ablation

Arrhythmogenic cardiomyopathy (ACM) is a group of arrhythmogenic disorders of the myocardium that are not caused by ischemic, hypertensive, or valvular heart disease. The clinical manifestations of ACMs may overlap those of dilated cardiomyopathy, complicating the differential diagnosis. In several ACMs, ventricular tachycardia (VT) has been observed at an early stage, regardless of the severity of the disease. Therefore, preventing recurrences of VT can be a clinical challenge. There is a wide range of efficacy and side effects associated with the use of antiarrhythmic drugs (AADs) in the treatment of VT. In addition to AADs, patients with ACM and ventricular tachyarrhythmias may benefit from catheter ablation, especially if they are drug-refractory. The differences in pathogenesis between the various types of ACMs can lead to heterogeneous distributions of arrhythmogenic substrates, non-uniform ablation strategies, and distinct ablation outcomes. Ablation has been documented to be effective in eliminating ventricular tachyarrhythmias in arrhythmogenic right ventricular dysplasia (ARVC), sarcoidosis, Chagas cardiomyopathy, and Brugada syndrome (BrS). As an entity that is rare in nature, ablation for ventricular tachycardia in certain forms of ACM may only be reported through case reports, such as amyloidosis and left ventricular noncompaction. Several types of ACMs, including ARVC, sarcoidosis, Chagas cardiomyopathy, BrS, and left ventricular noncompaction, may exhibit diseased substrates within or adjacent to the epicardium that may be accountable for ventricular arrhythmogenesis. As a result, combining endocardial and epicardial ablation is of clinical importance for successful ablation. The purpose of this article is to provide a comprehensive overview of the substrate characteristics, ablation strategies, and ablation outcomes of various types of ACMs using endocardial and epicardial approaches.

Combining 3-Dimensional Electroanatomic Mapping and Cardiac Magnetic Resonance

We present the case of a 17-year-old asymptomatic boy with a diagnosis of arrhythmogenic cardiomyopathy. Merging of cardiac magnetic resonance imaging and three-dimensional electroanatomic mapping provided striking visualization of the association between structural and electrical alterations and guided the decision to implant an implantable cardioverter defibrillator. (Level of Difficulty: Intermediate.)

Arrhythmogenic right ventricular cardiomyopathy in a Japanese patient with a homozygous founder variant of DSG2 in the East Asian population

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a hereditary cardiomyopathy that results in fatal arrhythmias and heart failure. Herein, we report a Japanese patient with ARVC whose parents were blood relatives. Genetic testing identified a homozygous rare variant, c.1592T > G (p.Phe531Cys), of DSG2 that is presumed to be a founder variant among East Asians. Genetic counseling sessions with precise risk assessment and appropriate follow-up programs were provided to the patient and family members.

Genetic Background and Clinical Features in Arrhythmogenic Left Ventricular Cardiomyopathy: A Systematic Review

In recent years a phenotypic variant of Arrhythmogenic cardiomyopathy has been described, characterized by predominant left ventricular (LV) involvement with no or minor right ventricular abnormalities, referred to as Arrhythmogenic left ventricular cardiomyopathy (ALVC). Different disease-genes have been identified in this form, such as Desmoplakin (DSP), Filamin C (FLNC), Phospholamban (PLN) and Desmin (DES). The main purpose of this critical systematic review was to assess the level of knowledge on genetic background and clinical features of ALVC. A search (updated to April 2022) was run in the PubMed, Scopus, and Web of Science electronic databases. The search terms used were “arrhythmogenic left ventricular cardiomyopathy” OR “arrhythmogenic cardiomyopathy” and “gene” OR “arrhythmogenic dysplasia” and “gene”. The most represented disease-gene turned out to be DSP, accounting for half of published cases, followed by FLNC. Overall, ECG abnormalities were reported in 58% of patients. Major ventricular arrhythmias were recorded in 26% of cases; an ICD was implanted in 29% of patients. A total of 6% of patients showed heart failure symptoms, and 15% had myocarditis-like episodes. DSP is confirmed to be the most represented disease-gene in ALVC patients. An analysis of reported clinical features of ALVC patients show an important degree of electrical instability, which frequently required an ICD implant. Moreover, myocarditis-like episodes are common.

Arrhythmogenic Cardiomyopathy: Diagnosis, Evolution, Risk Stratification and Pediatric Population-Where Are We?

Arrhythmogenic cardiomyopathy (ACM) is a cardiomyopathy characterized by the occurrence of a high risk of life-threatening ventricular arrhythmias and sudden cardiac death even at presentation. Diagnosis, evolution and outcomes in adults have been extensively reported, but little data in pediatric population are available. Risk stratification in this particular setting is still a matter of debate and new risk factors are needed in a model of an ever more "individualized medicine".

Understanding the molecular basis of cardiomyopathy

Inherited cardiomyopathies are a major cause of mortality and morbidity worldwide and can be caused by mutations in a wide range of proteins located in different cellular compartments. The present review is based on Dr. Ju Chen's 2021 Robert M. Berne Distinguished Lectureship of the American Physiological Society Cardiovascular Section, in which he provided an overview of the current knowledge on the cardiomyopathy-associated proteins that have been studied in his laboratory. The review provides a general summary of the proteins in different compartments of cardiomyocytes associated with cardiomyopathies, with specific focus on the proteins that have been studied in Dr. Chen's laboratory.

Multimodality Cardiac Imaging in Cardiomyopathies: From Diagnosis to Prognosis

Cardiomyopathies are a group of structural and/or functional myocardial disorders which encompasses hypertrophic, dilated, arrhythmogenic, restrictive, and other cardiomyopathies. Multimodality cardiac imaging techniques are the cornerstone of cardiomyopathy diagnosis; transthoracic echocardiography should be the first-line imaging modality due to its availability, and diagnosis should be confirmed by cardiovascular magnetic resonance, which will provide more accurate morphologic and functional information, as well as extensive tissue characterization. Multimodality cardiac imaging techniques are also essential in assessing the prognosis of patients with cardiomyopathies; left ventricular ejection fraction and late gadolinium enhancement are two of the main variables used for risk stratification, and they are incorporated into clinical practice guidelines. Finally, periodic testing with cardiac imaging techniques should also be performed due to the evolving and progressive natural history of most cardiomyopathies.

Cardiomyocyte Dysfunction in Inherited Cardiomyopathies

Inherited cardiomyopathies form a heterogenous group of disorders that affect the structure and function of the heart. Defects in the genes encoding sarcomeric proteins are associated with various perturbations that induce contractile dysfunction and promote disease development. In this review we aimed to outline the functional consequences of the major inherited cardiomyopathies in terms of myocardial contraction and kinetics, and to highlight the structural and functional alterations in some sarcomeric variants that have been demonstrated to be involved in the pathogenesis of the inherited cardiomyopathies. A particular focus was made on mutation-induced alterations in cardiomyocyte mechanics. Since no disease-specific treatments for familial cardiomyopathies exist, several novel agents have been developed to modulate sarcomere contractility. Understanding the molecular basis of the disease opens new avenues for the development of new therapies. Furthermore, the earlier the awareness of the genetic defect, the better the clinical prognostication would be for patients and the better the prevention of development of the disease.