Sudden cardiac death owing to arrhythmogenic right ventricular cardiomyopathy: Two case reports and systematic literature review

Arrhythmogenic Right Ventricular Cardiomyopathy Post-Mortem Assessment: A Systematic Review

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic disorder characterized by the progressive fibro-fatty replacement of the right ventricular myocardium, leading to myocardial atrophy. Although the structural changes usually affect the right ventricle, the pathology may also manifest with either isolated left ventricular myocardium or biventricular involvement. As ARVC shows an autosomal dominant pattern of inheritance with variable penetrance, the clinical presentation of the disease is highly heterogeneous, with different degrees of severity and patterns of myocardial involvement even in patients of the same familiar group with the same gene mutation: the pathology spectrum ranges from the absence of symptoms to sudden cardiac death (SCD) sustained by ventricular arrhythmias, which may, in some cases, be the first manifestation of an otherwise silent pathology. An evidence-based systematic review of the literature was conducted to evaluate the state of the art of the diagnostic techniques for the correct post-mortem identification of ARVC. The research was performed using the electronic databases PubMed and Scopus. A methodological approach to reach a correct post-mortem diagnosis of ARVC was described, analyzing the main post-mortem peculiar macroscopic, microscopic and radiological alterations. In addition, the importance of performing post-mortem genetic tests has been underlined, which may lead to the correct identification and characterization of the disease, especially in those ARVC forms where anatomopathological investigation does not show evident morphostructural damage. Furthermore, the usefulness of genetic testing is not exclusively limited to the correct diagnosis of the pathology, but is essential for promoting targeted screening programs to the deceased's family members. Nowadays, the post-mortem diagnosis of ARVC performed by forensic pathologist remains very challenging: therefore, the identification of a clear methodological approach may lead to both a reduction in under-diagnoses and to the improvement of knowledge on the disease.

Exploring the Potential of Proteome Analysis as a Promising Tool for Evaluation of Sudden Cardiac Death (SCD) in Forensic Settings: A Literature Review

Sudden cardiac death (SCD) represents a global emergency, with a high number of cases affecting all age groups every year. The prevention of these fatal events requires an accurate knowledge of etiology and pathogenesis, which can vary. Autopsy is an indispensable tool in cases of SCD for diagnostic purposes, as well as for judicial and preventive purposes for family members. Despite the completion of all routine post-mortem investigations, it is often complicated for the forensic pathologist to define the triggering cause of these events. The study of the proteome is proving to be extremely promising in the field of human cardiovascular disease. This paper aims to offer a literature review on the study of the proteome in post-mortem cadaveric biological samples obtained from SCD cases. The aim of this work is to outline the state of the art of the scientific advances that protein analysis can offer in the diagnosis of SCD and the limits that various studies have traced up to now. In conclusion, the work defines the future perspectives of this field in SCD, suggesting strategies to overcome the reported limits and improve the diagnostics of these events.

Diagnosis and management of arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic disorder of the myocardium that can lead to ventricular arrhythmia and sudden cardiac death. The condition has been identified as a significant cause of arrhythmic death among young people and athletes, therefore, early recognition of the disease by emergency clinicians is critical to prevent subsequent death. The diagnosis of ARVC can be very challenging and requires a systematic approach. This publication reviews the pathophysiology, classification, clinical presentations, and appropriate approach to diagnosis and management of ARVC.

Postmortem Genetic Testing in Sudden Unexpected Death: A Narrative Review

Sudden unexpected death (SUD) is one of the challenging situations encountered in forensic medicine. As a rule, a comprehensive forensic assessment is performed to identify the cause of death in such cases; however, the absence of findings suggestive of a cause, i.e., a negative autopsy, warrants further investigation such as a molecular autopsy. In this review, we aim to highlight the genetic causes of SUD, tools used in a molecular autopsy, and the role of screening in surviving relatives. As per several guidelines, the most preferred samples for DNA extraction are whole blood and fresh frozen tissues. Furthermore, Sanger sequencing and next-generation sequencing are the technologies that are used for genetic analysis; the latter overcomes the former's drawbacks in terms of cost-effectiveness, time consumption, and the ability to sequence the whole exome. SUD have diverse etiologies; we can generally classify them into cardiac and non-cardiac causes. Regarding cardiac causes, many conditions having an underlying genetic basis are included, such as channelopathies and cardiomyopathies. Regarding non-cardiac causes of SUD, the main etiologies are epilepsy and metabolic disorders. Nevertheless, it has been proposed that there is a genetic overlap between channelopathies, especially long QT syndromes and epilepsy. Additionally, fatty acid oxidation disorders are major metabolic conditions that are caused by certain genetic mutations that can lead to SUD in infancy. Since many SUD causes have an underlying genetic mutation, it is important to understand the genetic variations not only to recognize the cause of death but also to undertake further preventive measures for surviving relatives. In conclusion, a molecular autopsy has a major role in the forensic examination of cases of SUD.

Adipogenic Signaling Promotes Arrhythmia Substrates before Structural Abnormalities in TMEM43 ARVC

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic disorder of desmosomal and structural proteins that is characterized by fibro-fatty infiltrate in the ventricles and fatal arrhythmia that can occur early before significant structural abnormalities. Most ARVC mutations interfere with β-catenin-dependent transcription that enhances adipogenesis; however, the mechanistic pathway to arrhythmogenesis is not clear. We hypothesized that adipogenic conditions play an important role in the formation of arrhythmia substrates in ARVC. Cardiac myocyte monolayers co-cultured for 2-4 days with mesenchymal stem cells (MSC) were derived from human-induced pluripotent stem cells with the ARVC5 TMEM43 p.Ser358Leu mutation. The TMEM43 mutation in myocyte co-cultures alone had no significant effect on impulse conduction velocity (CV) or APD. In contrast, when co-cultures were exposed to pro-adipogenic factors for 2-4 days, CV and APD were significantly reduced compared to controls by 49% and 31%, respectively without evidence of adipogenesis. Additionally, these arrhythmia substrates coincided with a significant reduction in IGF-1 expression in MSCs and were mitigated by IGF-1 treatment. These findings suggest that the onset of enhanced adipogenic signaling may be a mechanism of early arrhythmogenesis, which could lead to personalized treatment for arrhythmias associated with TMEM43 and other ARVC mutations.

Left-dominant arrhythmogenic cardiomyopathy in a Fila Brasileiro dog

BACKGROUND

In human medicine, arrhythmogenic left ventricular cardiomyopathy was described as a primary disease of the heart characterized by fibroadipose replacement of the myocardium..

CASE DESCRIPTION

We report the case of a dog, with history of syncope and irregular cardiac rhythm. Electrocardiogram, echocardiography, and a 24-hour Holter monitoring showed, respectively, the presence of premature ventricular complexes with right bundle branch block morphology, an increase of the left ventricle end-diastolic diameter with preserved fractional shortening and ejection fraction, and a sinus arrhythmia as baseline rhythm with supraventricular tachycardia episodes and ventricular complexes with left bundle branch block morphology. After the death of the canine, a postmortem examination showed cardiomegaly. Fibroadipose replacement of the septum and both ventricles, with left ventricle myocardial fibrosis, suggestive of previous necrosis, was observed.

CONCLUSION

These findings are suggestive of left-dominant arrhythmogenic cardiomyopathy which, to the best of our knowledge, has not been described in veterinary medicine.

Arrhythmogenic Right Ventricular Cardiomyopathy in a Patient Experiencing Out-of-Hospital Ventricular Fibrillation Arrest Twice: Case Report and Review of the Literature

We present a case of a 62-year-old male who was admitted to the hospital with out-of-hospital ventricular fibrillation (VF) arrest. He had a VF arrest in 2011 and was admitted to another hospital. He had several investigations excluding cardiac magnetic resonance imaging, all of which were normal. He was playing tennis on both occasions when he experienced the VF arrest. His electrocardiogram on admission showed AF with partial right bundle branch block, inverted T waves in V1-V2, low voltage QRS complexes, ventricular ectopic in lead V1-V2, and prolonged QTc. His echocardiogram showed normal left ventricular function and a dilated right ventricle. Cardiac magnetic resonance imaging showed a dilated RV cavity size with impaired systolic function and dyskinetic region in the mid-ventricular free wall proximal to the insertion of the moderator band and late gadolinium enhancement in both right and left ventricles insertion points and mid-wall late gadolinium enhancement in the basal inferolateral wall suggestive of arrhythmogenic right ventricular cardiomyopathy. He had a single chamber VVI implantable cardioverter-defibrillator fitted for primary prevention and was discharged home. He had outpatient follow-up and showed good improvement and his implantable cardioverter-defibrillator checks were satisfactory and did not experience any shocks.

Cardiac Outpouchings: Definitions, Differential Diagnosis, and Therapeutic Approach

Background and Aims

Cardiac outpouchings encounter a series of distinct congenital or acquired entities (i.e. aneurysms, pseudoaneurysms, diverticula, and herniations), whose knowledge is still poorly widespread in clinical practice. This review aims to provide a comprehensive overview focusing on definition, differential diagnosis, and prognostic outcomes of cardiac outpouchings, as well as further insights on therapeutic options, in order to assist physicians in the most appropriate decision-making.

Methods

The material reviewed was obtained by the following search engines: MEDLINE (PubMed), EMBASE, Google Scholar, and Clinical Trials databases, from January 1966 until March 2021. We searched for the following keywords (in title and/or abstract): (“cardiac” OR “heart”) AND (“outpouching” OR “outpouch” OR “aneurysm” OR “pseudoaneurysm” OR “false aneurysm” OR “diverticulum” OR “herniation”). Review articles, original articles, case series, and case reports with literature review were included in our search. Data from patients with congenital or acquired cardiac outpouchings, from prenatal to geriatric age range, were investigated.

Results

Out of the 378 papers initially retrieved, 165 duplicates and 84 records in languages other than English were removed. Among the 129 remaining articles, 76 were included in our research material, on the basis of the following inclusion criteria: (a) papers pertaining to the research topic; (b) peer-reviewed articles; (c) using standardized diagnostic criteria; and (d) reporting raw prevalence data. Location, morphologic features, wall motion abnormalities, and tissue characterization were found to have a significant impact in recognition and differential diagnosis of cardiac outpouchings as well as to play a significant role in defining their natural history and prognostic outcomes.

Conclusions

Careful recognition of cardiac outpouchings remains a diagnostic challenge in clinical practice. Due to a broad cluster of distinctive and heterogeneous entities, their knowledge and timely recognition play a pivotal role in order to provide the most appropriate clinical management and therapeutic approach.

Anatomical-MRI Correlations in Adults and Children with Arrhythmogenic Right Ventricular Cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a rare disease in which the right ventricular myocardium is replaced by islands of fibro-adipose tissue. Therefore, ventricular re-entry circuits can occur, predisposing the patient to ventricular tachyarrhythmias, as well as dilation of the right ventricle that eventually leads to heart failure. Although it is a rare disease with low prevalence in Europe and the United States, many patients are addressed disproportionately for cardiac magnetic resonance imaging (MRI). The most severe consequence of this condition is sudden cardiac death at a young age due to untreated cardiac arrhythmias. The purpose of this paper is to revise the magnetic resonance characteristics of ARVC, including the segmental contraction abnormalities, fatty tissue replacement, decrease of the ejection fraction, and the global RV dilation. Herein, we also present several recent improvements of the 2010 Task Force criteria that are not included within the ARVC diagnosis guidelines. In our opinion, these features will be considered in a future Task Force Consensus.

Pathogenesis of arrhythmogenic cardiomyopathy: role of inflammation

Arrhythmogenic cardiomyopathy (AC) is an inherited disease characterized by progressive breakdown of heart muscle, myocardial tissue death, and fibrofatty replacement. In most cases of AC, the primary lesion occurs in one of the genes encoding desmosomal proteins, disruption of which increases membrane fragility at the intercalated disc. Disrupted, exposed desmosomal proteins also serve as epitopes that can trigger an autoimmune reaction. Damage to cell membranes and autoimmunity provoke myocardial inflammation, a key feature in early stages of the disease. In several preclinical models, targeting inflammation has been shown to blunt disease progression, but translation to the clinic has been sparse. Here we review current understanding of inflammatory pathways and how they interact with injured tissue and the immune system in AC. We further discuss the potential role of immunomodulatory therapies in AC.

[Anesthetic management in a patient with arrhythmogenic right ventricular cardiomyopathy and an implantable cardioverter defibrillator: a case report]

BACKGROUND AND OBJECTIVES

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic cardiomyopathy characterized by potentially lethal ventricular tachycardia. Here we describe a patient with ARVC and an Implantable Cardioverter Defibrillator (ICD) in whom maxillary sinus surgery was performed under general anesthesia.

CASE REPORT

The patient was a 59 year-old man who was scheduled to undergo maxillary sinus surgery under general anesthesia. He had been diagnosed as having ARVC 15 years earlier and had undergone implantation of an ICD in the same year. Electrocardiography showed an epsilon wave in leads II, aVR, and V1-V3. Cardiac function was within normal range on transthoracic echocardiography. The ICD was temporarily deactivated after the patient arrived in the operating room and an intravenous line was secured. An external defibrillator was kept on hand for immediate defibrillation if any electrocardiographic abnormality was detected. Remifentanil 0.3 μg/kg/min, fentanyl 0.1 mg, propofol 154 mg, and rocuronium 46 mg were administered for induction of anesthesia. Tracheal intubation was performed orally. Anesthesia was maintained oxygen 1.0 L.min^-1, air 2.0 L.min^-1, propofol 5.0-7.0 mg.kg^-1.h^-1, and remifentanil 0.1-0.25 μg.kg^-1.min^-1. The surgery was completed as scheduled and the ICD was reactivated. The patient was then extubated after administration of sugammadex 200 mg.

CONCLUSION

We report the successful management of anesthesia without lethal arrhythmia in a patient with ARVC and an ICD. An adequate amount of analgesia should be administered during general anesthesia to maintain adequate anesthetic depth and to avoid stress and pain.

Anesthetic management in a patient with arrhythmogenic right ventricular cardiomyopathy and an implantable cardioverter defibrillator: a case report

Background and objectives

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic cardiomyopathy characterized by potentially lethal ventricular tachycardia. Here we describe a patient with ARVC and an Implantable Cardioverter Defibrillator (ICD) in whom maxillary sinus surgery was performed under general anesthesia.

Case report

The patient was a 59 year-old man who was scheduled to undergo maxillary sinus surgery under general anesthesia. He had been diagnosed as having ARVC 15 years earlier and had undergone implantation of an ICD in the same year. Electrocardiography showed an epsilon wave in leads II, aVR, and V1–V3. Cardiac function was within normal range on transthoracic echocardiography. The ICD was temporarily deactivated after the patient arrived in the operating room and an intravenous line was secured. An external defibrillator was kept on hand for immediate defibrillation if any electrocardiographic abnormality was detected. Remifentanil 0.3 μg/kg/min, fentanyl 0.1 mg, propofol 154 mg, and rocuronium 46 mg were administered for induction of anesthesia. Tracheal intubation was performed orally. Anesthesia was maintained oxygen 1.0 L.min⁻¹, air 2.0 L.min⁻¹, propofol 5.0–7.0 mg.kg⁻¹.h⁻¹, and remifentanil 0.1–0.25 μg.kg⁻¹.min⁻¹. The surgery was completed as scheduled and the ICD was reactivated. The patient was then extubated after administration of sugammadex 200 mg.

Conclusion

We report the successful management of anesthesia without lethal arrhythmia in a patient with ARVC and an ICD. An adequate amount of analgesia should be administered during general anesthesia to maintain adequate anesthetic depth and to avoid stress and pain.

MicroRNA‑186‑5p is expressed highly in ethanol‑induced cardiomyocytes and regulates apoptosis via the target gene XIAP

Ethanol has a toxic effect on the heart, resulting in cardiomyocyte damage. Long-term high intake of ethanol leads to a non-ischemic dilated cardiomyopathy termed alcoholic cardiomyopathy (ACM). However, the pathogenesis of alcoholic cardiomyopathy remains unclear. The apoptosis of cardiomyocytes serves an important role in the pathogenesis of ACM. X-linked inhibitor of apoptosis protein (XIAP) is an important anti-apoptotic protein in human tissue cells. To the best of our knowledge, no studies have reported on its function in ethanol-induced cardiomyopathy. Previous works have screened the ACM-associated differentially expressed microRNAs (miRs), including miR-186-5p and miR-488-3p. TargetScan bioinformatics software was used to predict 949 target genes associated with miR-186-5p, and XIAP was demonstrated to be a target of miR-186-5p. The present study firstly analyzed the levels of apoptosis in ethanol-treated cardiomyocytes using flow cytometry. Alterations in the expression levels of miR-186-5p and XIAP were subsequently evaluated in ethanol-treated AC16 cardiomyocytes to assess the specific molecular mechanisms of ethanol-induced cardiomyocyte apoptosis. The levels of apoptosis in AC16 cardiomyocytes increased following ethanol treatment, and further increased with the rise in concentration and action time of ethanol. The expression levels of miR-186-5p were upregulated, and the expression levels of XIAP were downregulated in ethanol-treated cardiomyocytes. miR-186-5p may regulate ethanol-induced apoptosis in cardiomyocytes using XIAP as the direct target gene. This study provides a novel therapeutic target for the prevention and treatment of ACM.