Advances in the understanding of myocarditis

The potential emerging role of piRNA/PIWI complex in virus infection

P-element-induced wimpy testis-interacting RNAs (piRNAs), a class of small noncoding RNAs with about 24-32 nucleotides, often interact with PIWI proteins to form a piRNA/PIWI complex that could influence spermiogenesis, transposon silencing, epigenetic regulation, etc. PIWI proteins have a highly conserved function in a variety of species and are usually expressed in germ cells. However, increasing evidence has revealed the important role of the piRNA/PIWI complex in the occurrence and prognosis of various human diseases and suggests its potential application in the diagnosis and treatment of related diseases, becoming a prominent marker for these human diseases. Recent studies have confirmed that piRNA/PIWI complexes or piRNAs are abnormally expressed in some viral infections, effecting disease progression and viral replication. In this study, we reviewed the association between the piRNA/PIWI complex and several human disease-associated viruses, including human papillomavirus, human immunodeficiency virus, human rhinovirus, severe acute respiratory syndrome coronavirus 2, respiratory syncytial virus, and herpes simplex virus type 1.

European Association of Cardiovascular Imaging survey on cardiovascular multimodality imaging in acute myocarditis

AIMS

To assess the current role of cardiac imaging in the diagnosis, management, and follow-up of patients with acute myocarditis (AM) through a European Association of Cardiovascular Imaging survey.

METHODS AND RESULTS

A total of 412 volunteers from 74 countries responded to the survey. Most participants worked in tertiary centres (56%). All participants had access to echocardiography, while 79 and 75% had access to cardiac computed tomography angiography (CCTA) and cardiac magnetic resonance (CMR), respectively. Less than half (47%) had access to myocardial biopsy, and only 5% used this test routinely. CMR was performed within 7 days of presentation in 73% of cases. Non-ischaemic late gadolinium enhancement (LGE, 88%) and high-signal intensity in T2-weighted images (74%) were the most used diagnostic criteria for AM. CCTA was preferred to coronary angiography by 47% of participants to exclude coronary artery disease. Systematic prescription of beta-blockers and angiotensin-converting enzyme inhibitors was reported by 38 and 32% of participants. Around a quarter of participants declared considering LGE burden as a reason to treat. Most participants (90%) reported performing a follow-up echocardiogram, while 63% scheduled a follow-up CMR. The main reason for treatment discontinuation was improvement of left ventricular ejection fraction (89%), followed by LGE regression (60%). In two-thirds of participants, the decision to resume high-intensity sport was influenced by residual LGE.

CONCLUSION

This survey confirms the high utilization of cardiac imaging in AM but reveals major differences in how cardiac imaging is used and how the condition is managed between centres, underlining the need for recommendation statements in this topic.

Fulminant myocarditis induced by SARS-CoV-2 infection without severe lung involvement: insights into COVID-19 pathogenesis

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection often leads to pulmonary complications. Cardiovascular sequelae, including myocarditis and heart failure, have also been reported. Here, the study presents two fulminant myocarditis cases infected by SARS-CoV-2 exhibiting remarkable elevation of cardiac biomarkers without significant pulmonary injury, as determined by imaging examinations. Immunohistochemical staining reveals the viral antigen within cardiomyocytes, indicating that SARS-CoV-2 could directly infect the myocardium. The full viral genomes from respiratory, anal, and myocardial specimens are obtained via next-generation sequencing. Phylogenetic analyses of the whole genome and spike gene indicate that viruses in the myocardium/pericardial effusion and anal swabs are closely related and cluster together yet diverge from those in the respiratory samples. In addition, unique mutations are found in the anal/myocardial strains compared to the respiratory strains, suggesting tissue-specific virus mutation and adaptation. These findings indicate genetically distinct SARS-CoV-2 variants have infiltrated and disseminated within myocardial tissues, independent of pulmonary injury, and point to different infection routes between the myocardium and respiratory tract, with myocardial infections potentially arising from intestinal infection. These findings highlight the potential for systemic SARS-CoV-2 infection and the importance of a thorough multi-organ assessment in patients for a comprehensive understanding of the pathogenesis of COVID-19.

Infectious factors in myocarditis: a comprehensive review of common and rare pathogens

BACKGROUND

Myocarditis is a significant health threat today, with infectious agents being the most common cause. Accurate diagnosis of the etiology of infectious myocarditis is crucial for effective treatment.

MAIN BODY

Infectious myocarditis can be caused by viruses, prokaryotes, parasites, and fungi. Viral infections are typically the primary cause. However, some rare opportunistic pathogens can also damage heart muscle cells in patients with immunodeficiencies, neoplasms and those who have undergone heart surgery.

CONCLUSIONS

This article reviews research on common and rare pathogens of infectious myocarditis, emphasizing the complexity of its etiology, with the aim of helping clinicians make an accurate diagnosis of infectious myocarditis.

Loss of TRIM29 mitigates viral myocarditis by attenuating PERK-driven ER stress response in male mice

Viral myocarditis, an inflammatory disease of the myocardium, is a significant cause of sudden death in children and young adults. The current coronavirus disease 19 pandemic emphasizes the need to understand the pathogenesis mechanisms and potential treatment strategies for viral myocarditis. Here, we found that TRIM29 was highly induced by cardiotropic viruses and promoted protein kinase RNA-like endoplasmic reticulum kinase (PERK)-mediated endoplasmic reticulum (ER) stress, apoptosis, and reactive oxygen species (ROS) responses that promote viral replication in cardiomyocytes in vitro. TRIM29 deficiency protected mice from viral myocarditis by promoting cardiac antiviral functions and reducing PERK-mediated inflammation and immunosuppressive monocytic myeloid-derived suppressor cells (mMDSC) in vivo. Mechanistically, TRIM29 interacted with PERK to promote SUMOylation of PERK to maintain its stability, thereby promoting PERK-mediated signaling pathways. Finally, we demonstrated that the PERK inhibitor GSK2656157 mitigated viral myocarditis by disrupting the TRIM29-PERK connection, thereby bolstering cardiac function, enhancing cardiac antiviral responses, and curbing inflammation and immunosuppressive mMDSC in vivo. Our findings offer insight into how cardiotropic viruses exploit TRIM29-regulated PERK signaling pathways to instigate viral myocarditis, suggesting that targeting the TRIM29-PERK axis could mitigate disease severity.

Endomyocardial biopsy: safety and prognostic utility in paediatric and adult myocarditis in the European Society of Cardiology EURObservational Research Programme Cardiomyopathy and Myocarditis Long-Term Registry

BACKGROUND AND AIMS

Contemporary multicentre data on clinical and diagnostic spectrum and outcome in myocarditis are limited. Study aims were to describe baseline features, 1-year follow-up, and baseline predictors of outcome in clinically suspected or biopsy-proven myocarditis (2013 European Society of Cardiology criteria) in adult and paediatric patients from the EURObservational Research Programme Cardiomyopathy and Myocarditis Long-Term Registry.

METHODS

Five hundred eighty-one (68.0% male) patients, 493 adults, median age 38 (27-52) years, and 88 children, aged 8 (3-13) years, were divided into 3 groups: Group 1 (n = 233), clinically suspected myocarditis with abnormal cardiac magnetic resonance; Group 2 (n = 222), biopsy-proven myocarditis; and Group 3 (n = 126) clinically suspected myocarditis with normal or inconclusive or no cardiac magnetic resonance. Baseline features were analysed overall, in adults vs. children, and among groups. One-year outcome events included death/heart transplantation, ventricular assist device (VAD) or implantable cardioverter defibrillator (ICD) implantation, and hospitalization for cardiac causes.

RESULTS

Endomyocardial biopsy, mainly right ventricular, had a similarly low complication rate in children and adults (4.7% vs. 4.9%, P = NS), with no procedure-related death. A classical myocarditis pattern on cardiac magnetic resonance was found in 31.3% of children and in 57.9% of adults with biopsy-proven myocarditis (P < .001). At 1-year follow-up, 11/410 patients (2.7%) died, 7 (1.7%) received a heart transplant, 3 underwent VAD (0.7%), and 16 (3.9%) underwent ICD implantation. Independent predictors at diagnosis of death or heart transplantation or hospitalization or VAD implantation or ICD implantation at 1-year follow-up were lower left ventricular ejection fraction and the need for immunosuppressants for new myocarditis diagnosis refractory to non-aetiology-driven therapy.

CONCLUSIONS

Endomyocardial biopsy was safe, and cardiac magnetic resonance using Lake Louise criteria was less sensitive, particularly in children. Virus-negative lymphocytic myocarditis was predominant both in children and adults, and use of immunosuppressive treatments was low. Lower left ventricular ejection fraction and the need for immunosuppressants at diagnosis were independent predictors of unfavourable outcome events at 1 year.

High risk and low prevalence diseases: Myocarditis

INTRODUCTION

Myocarditis is a serious condition that carries with it a high rate of morbidity and mortality.

OBJECTIVE

This review highlights the pearls and pitfalls of myocarditis, including presentation, diagnosis, and management in the emergency department (ED) based on current evidence.

DISCUSSION

Myocarditis is an inflammatory syndrome of myocardium, most often resulting from a viral infection, that can cause life-threatening cardiovascular collapse. It has a highly variable presentation and no widely available specific diagnostic test, making it a challenging diagnosis. Emergency clinicians should obtain an electrocardiogram and perform bedside ultrasound to assess cardiac function. Treatment in the ED is largely supportive, focusing on resuscitation, cardiovascular support, cardiology specialist consultation, and appropriate disposition.

CONCLUSIONS

An understanding of myocarditis can assist emergency clinicians in diagnosing and managing this potentially deadly disease.

Cardiac magnetic resonance-based layer-specific strain in immune checkpoint inhibitor-associated myocarditis

AIMS

To assess the different imaging characteristics between corticosteroid-sensitive (CS) and corticosteroid-refractory (CR) immune checkpoint inhibitor-associated myocarditis (ICIaM) with cardiac magnetic resonance (CMR) and the potential CMR parameters in the early detection of CR ICIaM.

METHODS AND RESULTS

Thirty-five patients diagnosed with ICIaM and 30 age and gender-matched cancer patients without a history of ICI treatment were enrolled. CMR with contrast was performed within 2 days of clinical suspicion. Left ventricular ejection fraction (LVEF) and late gadolinium enhancement (LGE) were assessed by CMR. LV sub-endocardial (GLSendo) and sub-epicardial (GLSepi) global longitudinal strains were quantified by offline feature tracking analysis. CS and CR ICIaM were defined based on the trend of Troponin I and clinical course during corticosteroid treatment. All 35 patients presented with non-fulminant symptoms upon initial assessment. Twenty patients (57.14%) were sensitive, and 15 (42.86%) were refractory to corticosteroids. Compared with controls, 22 patients (62.86%) with ICIaM developed LGE. LVEF decreased in CR ICIaM compared with the CS group and controls. GLSendo (-14.61 ± 2.67 vs. -18.50 ± 2.53, P < 0.001) and GLSepi (-14.75 ± 2.53 vs. -16.68 ± 2.05, P < 0.001) significantly increased in patients with CR ICIaM compared with the CS ICIaM. In patients with CS ICIaM, although GLSepi (-16.68 ± 2.05 vs. -19.31 ± 1.80, P < 0.001) was impaired compared with the controls, GLSendo was preserved. There was no difference in CMR parameters between LGE-positive and negative groups. LVEF, GLSendo, and GLSepi were predictors of CR ICIaM. When LVEF, GLSendo, and GLSepi were included in multivariate analysis, only GLSendo remained an independent predictor of CR ICIaM (OR: 2.170, 95% CI: 1.189-3.962, P = 0.012). A GLSendo of ≥-17.10% (sensitivity, 86.7%; specificity, 80.0%; AUC, 0.860; P < 0.001) could predict CR ICIaM in the ICIaM cohort. Kaplan-Meier analysis showed that in patients with impaired GLSendo of ≥-17.10%, cardiovascular adverse events (CAEs) occurred much earlier than in patients with preserved GLSendo of <-17.10% (Log-rank test P = 0.017).

CONCLUSIONS

CR and CS ICIaM demonstrated different functional and morphological characteristics in different myocardial layers. An impaired GLSendo could be a helpful parameter in early identifying corticosteroid-refractory individuals in the ICIaM population.

Paradigm shift in myocarditis treatment

Although most cases of myocarditis are self-limiting with a gradual improvement in cardiac function, the involvement of myocarditis in sudden cardiac death among children and young adults remains substantial, with rates of 3-17 % and 8.6-12 %, respectively. Moreover, the risk of developing chronic dilated cardiomyopathy ranges from 21 % to 30 % in all cases confirmed by biopsy. Current therapeutic strategies for myocarditis and its complications range from standard supportive care for heart failure and arrhythmias to etiologically oriented, case-based therapeutic options. For example, immunosuppression is indicated only in certain forms of acute myocarditis with clinical or endomyocardial biopsy evidence of immune checkpoint inhibitor-induced myocarditis and autoimmune diseases, including giant cell myocarditis, eosinophilic myocarditis, vasculitis, or cardiac sarcoidosis. However, our views on myocarditis treatment have changed considerably over the past two decades, thanks to the emergence of regenerative cells/tissues as well as drug and gene delivery systems. Cell-based therapies are now growing in popularity in any field of medicine. Studies evaluating the therapeutic efficacy of different stem cells in the treatment of acute myocarditis and its chronic complications have shown that although the experimental characteristics varied from study to study, in general, these strategies reduced inflammation and myocardial fibrosis while preventing myocarditis-induced systolic dysfunction and adverse remodeling in animal models.

Ivabradine Alleviates Experimental Autoimmune Myocarditis-Mediated Myocardial Injury

Ivabradine (IVA) reduces heart rate by inhibiting hyperpolarization-activated cyclic nucleotide-gated channels (HCNs), which play a role in the promotion of pacemaker activity in cardiac sinoatrial node cells. HCNs are highly expressed in neural and myocardial tissues and are involved in the modulation of inflammatory neuropathic pain. However, whether IVA exerts any effect on myocardial inflammation in the pathogenesis of heart failure is unclear. We employed single-cell RNA sequencing (scRNA-seq) in porcine cardiac myosin-induced experimental autoimmune myocarditis rat model to determine the effects and mechanisms of IVA. Lewis rats (n = 32) were randomly divided into the normal, control, high-dose-IVA, and low-dose-IVA groups. Heart rate and blood pressure were measured on days 0 and 21, respectively. Echocardiography was performed on day 22, and inflammation of the myocardium was evaluated via histopathological examination. Western blot was employed to detect the expression of HCN1-4, MinK-related protein 1 (MiRP1), matrix metalloproteinase 2 (MMP-2), MMP-9, and transforming growth factor-β (TGF-β). Furthermore, enzyme-linked immunosorbent assay was performed to measure serum IL-1, IL-6, and TNF-α. The relative mRNA levels of collagen I, collagen III, and α-smooth muscle actin (α-SMA) were determined via qRT-PCR. We found that IVA reduced the total number of cells infiltrated into the myocardium, particularly in the subset of fibroblasts, endocardia, and monocytes. IVA administration ameliorated cardiac inflammation and reduced collagen production. Results of the echocardiography indicated that left ventricular internal diameter at end-systole LVIDs increased whereas left ventricular ejection fraction and left ventricular fractional shortening decreased in the control group. IVA improved cardiac performance. The expression of HCN4 and MiRP1 protein and the level of serum IL-1, IL-6, and TNF-α were decreased by IVA treatment. In conclusion, HCNs and the helper proteins were increased in the profile of myocardial inflammation. HCNs may be involved in the regulation of myocardial inflammation by inhibiting immune cell infiltration. Our findings can contribute to the development of IVA-based combination therapies for the future treatment of cardiac inflammation and heart failure.

Establishment and validation of a prediction model for myocarditis in Chinese children below 14 years old: a protocol for a retrospective cohort study

INTRODUCTION

Paediatric myocarditis, a rare inflammatory disease, often presents without clear early symptoms. Although cardiac troponin I levels can aid in diagnosing myocarditis, they are not definitive indicators. Troponin I levels frequently fluctuate within and outside the reference range, potentially causing misinterpretations by clinicians. Although a negative troponin I result is valuable for excluding myocarditis, its specificity is low. Moreover, the clinical diagnosis of paediatric myocarditis is exceptionally challenging, and accurate early-stage diagnosis and treatment pose difficulties. Currently, the Dallas criteria, involving cardiac biopsy, serves as the gold standard for myocarditis diagnosis. However, this method has several drawbacks and is unsuitable for children, resulting in its limited use.

METHODS AND ANALYSIS

In this study, we will employ multiple logistic regression analysis to develop a predictive model for early childhood myocarditis. This model will assess the patient's condition at onset and provide the probability of a myocarditis diagnosis. Model performance will be evaluated for accuracy and calibration, and the results will be presented through receiver operating characteristic (ROC) curves and calibration plots. Clinical decision curve analysis, in conjunction with ROC curve analysis, will be employed to determine the optimal cut-off value and calculate the net clinical benefit value for assessing clinical effectiveness. Finally, internal model validation will be conducted using bootstrapping.

ETHICS AND DISSEMINATION

Approval from the Clinical Research Ethics Committee of The Third Affiliated Hospital of Wenzhou Medical University has been obtained. The research findings will be disseminated through presentations at scientific conferences and publication in peer-reviewed journals.

Cardiovascular implications of inflammatory bowel disease: An updated review

Emerging data highlights the heightened risk of atherosclerotic cardiovascular diseases (ASCVD) in patients with chronic inflammatory disorders, particularly those afflicted with inflammatory bowel disease (IBD). This review delves into the epidemiological connections between IBD and ASCVD, elucidating potential underlying mechanisms. Furthermore, it discusses the impact of current IBD treatments on cardiovascular risk. Additionally, the cardiovascular adverse effects of novel small molecule drugs used in moderate-to-severe IBD are investigated, drawing parallels with observations in patients with rheumatoid arthritis. This article aims to comprehensively evaluate the existing evidence supporting these associations. To achieve this, we conducted a meticulous search of PubMed, spanning from inception to August 2023, using a carefully selected set of keywords. The search encompassed topics related to IBD, such as Crohn's disease and ulcerative colitis, as well as ASCVD, including coronary artery disease, cardiovascular disease, atrial fibrillation, heart failure, conduction abnormalities, heart blocks, and premature coronary artery disease. This review encompasses various types of literature, including retrospective and prospective cohort studies, clinical trials, meta-analyses, and relevant guidelines, with the objective of providing a comprehensive overview of this critical intersection of inflammatory bowel disease and cardiovascular health.

Inpatient Outcomes for Myocarditis-Related Heart Failure

Background  Heart failure (HF) is one of the leading causes of hospitalizations among adults, accounting for high rates of morbidity and mortality in the United States. Myocarditis is a less common etiology of HF, and its outcomes are less well understood. Methods  We used the Nationwide Readmissions Database from 2016 to 2019, extracting adult patients with a primary diagnosis of HF who were admitted between January and November of each year studied. We excluded patients with missing data on event time or length of stay. Inpatient outcomes were compared between cases of HF without myocarditis and myocarditis-associated HF (MAHF). Survey procedures were applied. Propensity scores as covariates were used in survey-weighted models to estimate the population average treatment effect on the treated using SAS 9.4. Results  We included 4,454,272 HF-related weighted admissions for which 4,605 patients (0.1%) had a concurrent diagnosis of myocarditis. Overall, patients with MAHF, compared with HF without myocarditis, were younger (mean age: 53 years vs. 72 years, p  < 0.001) with fewer women (45 vs. 48%), respectively. Patients with MAHF had more inpatient complications including cardiac arrest, cardiogenic shock, and use of mechanical circulatory support ( p  < 0.001) despite having fewer comorbidities such as diabetes, hypertension, and renal disease. Patients with MAHF had longer mean lengths of stay (9.2 vs. 5.5 days, p  < 0.001). In-hospital mortality during index admission was significantly higher in MAHF at 3.9% compared with 2.8% for HF without myocarditis ( p  < 0.001). Myocarditis was a key predictor of inpatient mortality adjusting for risk factors. Conclusion  Myocarditis-related HF is associated with increased inpatient mortality, resource utilization, and prolonged hospitalization.

Prospective Clinical Trials to Advance the Study of Immune Checkpoint Inhibitor Toxicity

Immune checkpoint inhibitors (ICIs) are a class of drug that produces durable and sustained anti-tumour responses in a wide variety of malignancies. The exponential rise in their use has been mirrored by a rise in immune-related adverse events (IrAEs). Knowledge of such toxicities, as well as effective management algorithms for these toxicities, is essential to optimize clinical efficacy and safety. Currently, the guidelines for management of the IrAEs are based largely on retrospective studies and case series. In this article, we review the current landscape of clinical trials investigating the management of IrAEs with an aim to develop standardised, randomised controlled trial-based management algorithms for ICI-related toxicities.

Roles of inflammasomes in viral myocarditis

Viral myocarditis (VMC), characterized by viral infection-induced inflammation, is a life-threatening disease associated with dilated cardiomyopathy or heart failure. Innate immunity plays a crucial role in the progression of inflammation, in which inflammasomes provide a platform for the secretion of cytokines and mediate pyroptosis. Inflammasomes are rising stars gaining increasing attention. The nucleotide oligomerization domain-, leucine-rich repeat-, and pyrin domain-containing protein 3 (NLRP3) inflammasome, the caspase recruitment domain-containing protein 8 (CARD8) inflammasome, and the caspase-11 inflammasome are three inflammasomes that were reported to affect the process and prognosis of VMC. These inflammasomes can be activated by a wide range of cellular events. Accumulating evidence has suggested that inflammasomes are involved in different stages of VMC, including the trigger and progression of myocardial injury and remodeling after infection. In this review, we summarized the pathways involving inflammasomes in VMC and discussed the potential therapies targeting inflammasomes and related pathways.

Myocardial Immune Cells: The Basis of Cardiac Immunology

The mammalian heart is characterized by the presence of striated myocytes, which allow continuous rhythmic contraction from early embryonic development until the last moments of life. However, the myocardium contains a significant contingent of leukocytes from every major class. This leukocyte pool includes both resident and nonresident immune cells. Over recent decades, it has become increasingly apparent that the heart is intimately sensitive to immune signaling and that myocardial leukocytes exhibit an array of critical functions, both in homeostasis and in the context of cardiac adaptation to injury. Here, we systematically review current knowledge of all major leukocyte classes in the heart, discussing their functions in health and disease. We also highlight the connection between the myocardium, immune cells, lymphoid organs, and both local and systemic immune responses.

Role of advanced cardiovascular imaging in chemotherapy-induced cardiotoxicity

The development of cardiotoxicity induced by cancer treatments has emerged as a significant clinical problem, both in the short run, as it may influence drug administration in chemotherapeutic protocols, and in the long run, because it may determine adverse cardiovascular outcomes in survivors of various malignant diseases. Therefore, early detection of anticancer drug-related cardiotoxicity is an important clinical target to improve prevention of adverse effects and patient care. Today, echocardiography is the first-line cardiac imaging techniques used for identifying cardiotoxicity. Cardiac dysfunction, clinical and subclinical, is generally diagnosed by the reduction of left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS). However, myocardial injury detected by echocardiography is preceded by other alterations, such as myocardial perfusion and mitochondrial and metabolic dysfunction, that can only be recognized by second-level imaging techniques, like cardiac magnetic resonance (CMR) and nuclear imaging, which, using targeted radiotracers, may help to provide information on the specific mechanisms of cardiotoxicity. In this review, we focus on the current and emerging role of CMR, as a critical diagnostic tool of cardiotoxicity in the very early phase, due to its availability and because it allows the contemporary detection of functional alterations, tissue alterations (mainly performed using T1, T2 mapping with the evaluation of extracellular volume-ECV) and perfusional alteration (evaluated with rest-stress perfusion) and, in the next future, even metabolic changes. Moreover, in the subsequent future, the use of Artificial Intelligence and big data on imaging parameters (CT, CMR) and oncoming molecular imaging datasets, including differences for gender and countries, may help predict cardiovascular toxicity at its earliest stages, avoiding its progression, with precise tailoring of patients' diagnostic and therapeutic pathways.

Corticosteroid in anti-inflammatory treatment of pediatric acute myocarditis: a systematic review and meta-analysis

BACKGROUND

To evaluate the efficacy of corticosteroids in anti-inflammatory treatment of pediatric acute myocarditis.

METHODS

We searched PubMed, Embase and Cochrane library and included studies before October 2022 for clinical trials, observational studies and retrospective studies which reported on children with acute myocarditis treated with corticosteroid anti-inflammatory therapy. The quality of the clinical trials was assessed by Jadad score as an exclusion criterion.

RESULTS

This systematic review included 6 studies involving 604 pediatric patients with acute myocarditis. Corticosteroid therapy was not associated with reduced risk of mortality due to acute myocarditis (P = 0.53; RR = 0.87; 95% CI = 0.58 to 1.33) compared to anti-failure treatment. There was a significant improvement in pediatric patients' left ventricular function measured by left ventricular ejection fraction in the group on corticosteroid anti-inflammatory treatment (P = 0.0009; MD = 11.93%; 95% CI = 4.87% to 18.99%). No conclusion can be drawn due to the high heterogeneity in meta-analyses of risk of getting to a clinical endpoint (death or heart transplantation) and changes in left ventricular end-diastolic diameter (LVEDD).

CONCLUSIONS

Corticosteroid anti-inflammatory therapy in pediatric acute myocarditis patients showed no significant improvement in reducing the risk of mortality, but showed significant improvement in LVEF.

COVID-19-Induced Myocarditis: Pathophysiological Roles of ACE2 and Toll-like Receptors

The clinical manifestations of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection responsible for coronavirus disease 2019 (COVID-19) commonly include dyspnoea and fatigue, and they primarily involve the lungs. However, extra-pulmonary organ dysfunctions, particularly affecting the cardiovascular system, have also been observed following COVID-19 infection. In this context, several cardiac complications have been reported, including hypertension, thromboembolism, arrythmia and heart failure, with myocardial injury and myocarditis being the most frequent. These secondary myocardial inflammatory responses appear to be associated with a poorer disease course and increased mortality in patients with severe COVID-19. In addition, numerous episodes of myocarditis have been reported as a complication of COVID-19 mRNA vaccinations, especially in young adult males. Changes in the cell surface expression of angiotensin-converting enzyme 2 (ACE2) and direct injury to cardiomyocytes resulting from exaggerated immune responses to COVID-19 are just some of the mechanisms that may explain the pathogenesis of COVID-19-induced myocarditis. Here, we review the pathophysiological mechanisms underlying myocarditis associated with COVID-19 infection, with a particular focus on the involvement of ACE2 and Toll-like receptors (TLRs).

Prognostic Significance of Cardiac Magnetic Resonance in Left Atrial and Biventricular Strain Analysis during the Follow-Up of Suspected Myocarditis

To assess the variation in left atrial (LA) and biventricular strain and its prognostic value in the course of suspected myocarditis, this retrospective study included 55 patients with clinically suspected myocarditis who underwent cardiac magnetic resonance (CMR) examinations at baseline and follow-up periods. Cine images were used for feature tracking analysis. Paired Student's t test, McNemar's test, and Cox proportional hazard regression were used for statistical analysis. The LA total emptying fraction was the only functional index that showed a statistically significant improvement. The initial LA peak's late negative strain rate (SRa) was the only parameter with a significant predictive power of major adverse cardiac events under univariable (hazard ratio [HR] 2.396, 95% confidence interval [CI] 1.044-5.498, p = 0.039) and multivariable Cox survival analysis when adjusted by LA strain parameters (HR 5.072, 95% CI 1.478-17.404, p = 0.010), LA strain and functional parameters (HR 7.197, 95% CI 1.679-30.846, p = 0.008), and LA and biventricular strain and functional parameters (HR 10.389, 95% CI 2.250-47.977, p = 0.003). Thus, our findings indicate that CMR strain is useful for monitoring LA and ventricular function in suspected myocarditis, that LA function may recover preceding ventricular function changes, and that LA strain may serve as an incremental tool to predict adverse outcomes.

Treating Pediatric Myocarditis with High Dose Steroids and Immunoglobulin

There is considerable variability in practice among pediatric centers for treatment of myocarditis. We report outcomes using high dose steroids in conjunction with IVIG. This is a single center retrospective study of children < 21 years of age diagnosed with myocarditis and treated with high dose steroids and IVIG from January 2004-April 2021. Diagnostic criteria for myocarditis included positive endomyocardial biopsy, cardiac magnetic resonance (CMR) imaging meeting Lake Louise criteria, or strictly defined clinical diagnosis. Forty patients met inclusion criteria. Median age at diagnosis was 11.6 years (0.7-14.6). Diagnosis was made clinically in 70% of cases (N = 28), by CMR in 12.5% (N = 5) and by biopsy in 17.5% (N = 7). Median ejection fraction (EF) at diagnosis was 35% (IQR 24-48). Median duration of IV steroids was 7 days (IQR 4-12) followed by an oral taper. Median cumulative dose of IV immunoglobulin (IVIG) was 2 g/kg. There were no serious secondary bacterial infections after steroid initiation. Ten patients (25%) required mechanical circulatory support. Overall transplant free survival was 92.5% with median follow-up of 1 year (IQR 0-6 years). Six patients required re-admission for cardiovascular reasons. By 3 months from diagnosis, 70% of patients regained normal left ventricular function. High dose steroids in conjunction with IVIG to treat acute myocarditis can be safe without significant infections or long-term side effects. Our cohort had excellent recovery of ventricular function and survival without transplant. Prospective comparison of a combination of high dose steroids with IVIG versus other therapies is needed.

QiShenYiQi pill for myocardial collagen metabolism and apoptosis in rats of autoimmune cardiomyopathy

CONTEXT

QiShenYiQi pill (QSYQ) is a traditional Chinese medicine with a myocardial protective effect.

OBJECTIVE

To explore the effect of QSYQ on myocardial collagen metabolism in rats with autoimmune cardiomyopathy and explore the underlying mechanism from the aspect of apoptosis.

MATERIALS AND METHODS

We established an autoimmune cardiomyopathy model using Lewis rats. The rats were then randomly divided into six groups (n = 8): control, model, 3-methyladenine (15 mg/kg, intraperitoneal injection), QSYQ low-dose (135 mg/kg, gavage), QSYQ medium dose (270 mg/kg, gavage), and QSYQ high-dose (540 mg/kg, gavage) for four weeks. Van Gieson staining was applied for myocardial pathological characteristics, TUNEL fluorescence for myocardial cell apoptosis, enzyme-linked immunosorbent assay (ELISA) for serum PICP, PIIINP, and CTX-I levels, and western blot analysis for type I/III myocardial collagen, Bcl-2, Bax, and caspase-3 proteins.

RESULTS

Results showed that QSYQ (135, 270, or 540 mg/kg) significantly reduced the expression of myocardial type I/III collagen, and concentrations of serum PICP, PIIINP, and CTX-I in rats. Moreover, QSYQ could alleviate myocardial fibrosis more effectively at a higher dose. QSYQ could also inhibit myocardial apoptosis via downregulating Bcl-2 expression, and upregulating Bax and caspase-3 expression levels.

DISCUSSION AND CONCLUSIONS

The QSYQ can improve myocardial collagen metabolism by inhibiting apoptosis, which provides a potential therapeutic approach for autoimmune cardiomyopathy.

Radiomics analysis of short tau inversion recovery images in cardiac magnetic resonance for the prediction of late gadolinium enhancement in patients with acute myocarditis

RATIONALE AND OBJECTIVES

Cardiac Magnetic Resonance (CMR) imaging is recommended as the reference diagnostic non-invasive modality for myocarditis but is often limited by patients' compliance. The purpose of this study is to evaluate the validity of Radiomics applied to Short Tau Inversion Recovery (STIR) sequences, in predicting the presence of LGE in patients with suspected acute myocarditis.

MATERIALS AND METHODS

171 STIR images on short-axis view were segmented with "MaZda" software ver 4.6, by placing a region of interest (ROI) on the left ventricle by two radiologists in consensus. Images were classified according to the presence of LGE in the equivalent short-axis T1-IR slice. A total of 337 ROI features were extracted for each image. Dataset was then split into two parts (train and test set) with 70:30 ratio.

RESULTS

Eleven classification models were trained. An Ensemble Machine Learning (EML) model was obtained by averaging the predictions of models with accuracy on test set >70%. The EML documented accuracy of 0.75, sensitivity of 0.8 and a specificity of 0.73 with a NPV of 0.81 and a PPV of 0.7, with AUC of 0.79 (95% CI: 0.66-0.92).

CONCLUSION

Radiomics and machine learning analysis could be a promising approach in reducing scan times without reducing diagnostic accuracy in predicting LGE in patients with acute myocarditis.

Micro-Players of Great Significance-Host microRNA Signature in Viral Infections in Humans and Animals

Over time, more and more is becoming known about micro-players of great significance. This is particularly the case for microRNAs (miRNAs; miR), which have been found to participate in the regulation of many physiological and pathological processes in both humans and animals. One such process is viral infection in humans and animals, in which the host miRNAs—alone or in conjunction with the virus—interact on two levels: viruses may regulate the host’s miRNAs to evade its immune system, while the host miRNAs can play anti- or pro-viral roles. The purpose of this comprehensive review is to present the key miRNAs involved in viral infections in humans and animals. We summarize the data in the available literature, indicating that the signature miRNAs in human viral infections mainly include 12 miRNAs (i.e., miR-155, miR-223, miR-146a, miR-122, miR-125b, miR-132, miR-34a, miR -21, miR-16, miR-181 family, let-7 family, and miR-10a), while 10 miRNAs are commonly found in animals (i.e., miR-155, miR-223, miR-146a, miR-145, miR-21, miR-15a/miR-16 cluster, miR-181 family, let-7 family, and miR-122) in this context. Knowledge of which miRNAs are involved in different viral infections and the biological functions that they play can help in understanding the pathogenesis of viral diseases, facilitating the future development of therapeutic agents for both humans and animals.

Engineered coxsackievirus B3 containing multiple organ-specific miRNA targets showed attenuated viral tropism and protective immunity

Coxsackievirus B3 (CVB3) can cause viral myocarditis, pancreatitis, and aseptic meningitis. This study aimed to construct an engineered CVB3 harboring three different tissue-specific miRNA targets (CVB3-miR3*T) to decrease the virulence of CVB3 in muscles, pancreas, and brain. CVB3-miR3*T and CVB3-miR-CON (containing three sequences not found in the human genome) were engineered and replicated in HELA cells. A viral plaque assay was used to determine the titers in HELA cells and TE671 cells (high miRNA-206 expression), MIN-6 cells (high miRNA-29a-3p expression), and mouse astrocytes (high miRNA-124-3p expression). We found that engineered CVB3 showed attenuated replication and reduced cytotoxicity, the variability of each type of cell was also increased in the CVB3-miR3*T group. Male BALB/c mice were infected to determine the LD50 and examine heart, pancreas, and brain titers and injury. Viral replication of the engineered viruses was restricted in infected mouse heart, pancreas, and brain, and viral plaques were about 100 fold lower compared with the control group. Mice immunized using CVB3-miR3*T, UV-inactivated CVB3-WT, and CVB3-miR-CON were infected with 100 × LD50 of CVB3-WT to determine neutralization. CVB3-miRT*3-preimmunized mice exhibited complete protection and remained alive after lethal virus infection, while only 5/15 were alive in the UV-inactivated mice, and all 15 mice were dead in the PBS-immunized group. The results demonstrate that miR-206-, miRNA-29a-3p-, and miRNA-124-3p-mediated CVB3 detargeting from the pancreas, heart, and brain might be a highly effective strategy for viral vaccine development.

Pathogenic Variants in Cardiomyopathy Disorder Genes Underlie Pediatric Myocarditis—Further Impact of Heterozygous Immune Disorder Gene Variants?

Myocarditis is an inflammatory disease of the heart. Pediatric myocarditis with the dilated cardiomyopathy (DCM) phenotype may be caused by likely pathogenic or pathogenic genetic variants [(L)P] in cardiomyopathy (CMP) genes. Systematic analysis of immune disorder gene defects has not been performed so far. We analyzed 12 patients with biopsy-proven myocarditis and the DCM phenotype together with their parents using whole-exome sequencing (WES). The WES data were filtered for rare pathogenic variants in CMP (n = 89) and immune disorder genes (n = 631). Twelve children with a median age of 2.9 (1.0–6.8) years had a mean left ventricular ejection fraction of 28% (22–32%) and myocarditis was confirmed by endomyocardial biopsy. Patients with primary immunodeficiency were excluded from the study. Four patients underwent implantation of a ventricular assist device and subsequent heart transplantation. Genetic analysis of the 12 families revealed an (L)P variant in the CMP gene in 8/12 index patients explaining DCM. Screening of recessive immune disorder genes identified a heterozygous (L)P variant in 3/12 index patients. This study supports the genetic impact of CMP genes for pediatric myocarditis with the DCM phenotype. Piloting the idea that additional immune-related genetic defects promote myocarditis suggests that the presence of heterozygous variants in these genes needs further investigation. Altered cilium function might play an additional role in inducing inflammation in the context of CMP.

A Case of Acute Pericarditis After COVID-19 Vaccination

A two-dose regimen of Pfizer-BioNTech COVID-19 vaccination confers 95% protection against COronaVIrus Disease 19 (COVID-19) and the safety profile is adequate. To the submission date, there were no reports in literature of acute pericarditis after BNT162b2 vaccination. However, pericarditis has been reported as a rare event associated with COVID-19 infection, which could be due to the pro-inflammatory effects of the spike protein. Recent evidence of post-vaccine myocarditis has been published. Herein we describe the case of a middle-aged healthy women who developed symptoms and signs of acute pericarditis 7-10 days after the second dose of Pfizer-BioNTech COVID-19 vaccination. Although a direct effect cannot be stated, it is important to report a potential adverse vaccine reaction effect that could be associated with the expression of SARS-CoV-2 spike protein induced from the mRNA of the vaccine.

Myocarditis following COVID-19 vaccination: incidence, mechanisms, and clinical considerations

INTRODUCTION

Vaccines have demonstrated protection against the morbidity and mortality of COVID-19, but concerns regarding the rare side effect of acute myocarditis have stymied immunization efforts. This review aims to describe the incidence and theorized mechanisms of COVID vaccine-associated myocarditis and review relevant principles for management of vaccine-associated myocarditis.

AREAS COVERED

Epidemiologic studies of myocarditis after COVID vaccination are reviewed, which show an incidence of approximately 20-30 per million patients. The vast majority of these cases are seen with mRNA vaccines especially in male patients under 30 years of age. Mechanisms are largely theoretical, but molecular mimicry and dysregulated innate immune reactions have been proposed. While studies suggest that this subtype of myocarditis is mild and self-limited, long-term evidence is lacking. Principles of myocarditis treatment and surveillance are outlined as they apply to COVID vaccine-associated myocarditis.

EXPERT OPINION

COVID vaccine-associated myocarditis is rare but well described in certain at-risk groups. Better understanding of its pathogenesis is key to mitigating this complication and advancing vaccination efforts. Risk-benefit analyses demonstrate that individual- and population-level benefits of vaccination exceed the risks of this rare and mild form of myocarditis.

Clinical characteristics and outcome of biopsy-proven myocarditis in children - Results of the German prospective multicentre registry "MYKKE"

BACKGROUND

Heart failure (HF) due to myocarditis might not respond in the same way to standard therapy as HF due to other aetiologies. The aim of this study was to investigate the value of endomyocardial biopsies (EMB) for clinical decision-making and its relation to the outcome of paediatric patients with myocarditis.

METHODS

Clinical and EMB data of children with myocarditis collected for the MYKKE-registry between 2013 and 2020 from 23 centres were analysed. EMB studies included histology, immunohistology, and molecular pathology. The occurrence of major adverse cardiac events (MACE) including mechanical circulatory support (MCS), heart transplantation, and/or death was defined as a combined endpoint.

RESULTS

Myocarditis was diagnosed in 209/260 patients: 64% healing/chronic lymphocytic myocarditis, 23% acute lymphocytic myocarditis (AM), 14% healed myocarditis, no giant cell myocarditis. The median age was 12.8 (1.4-15.9) years. Time from symptom-onset to EMB was 11.0 (4.0-29.0) days. Children with AM and high amounts of mononuclear cell infiltrates were significantly younger with signs of HF compared to those with healing/chronic or healed myocarditis. Myocardial viral DNA/RNA detection had no significant effect on outcome. The worst event-free survival was seen in patients with healing/chronic myocarditis (24%), followed by acute (31%) and healed myocarditis (58%, p = 0.294). A weaning rate of 64% from MCS was found in AM.

CONCLUSIONS

EMB provides important information on the type and stage of myocardial inflammation and supports further decision-making. Children with fulminant clinical presentation, high amounts of mononuclear cell infiltrates or healing/chronic inflammation and young age have the highest risk for MACE.

A Review of the Role of Imaging Modalities in the Evaluation of Viral Myocarditis with a Special Focus on COVID-19-Related Myocarditis

Viral myocarditis is inflammation of the myocardium secondary to viral infection. The clinical presentation of viral myocarditis is very heterogeneous and can range from nonspecific symptoms of malaise and fatigue in subclinical disease to a more florid presentation, such as acute cardiogenic shock and sudden cardiac death in severe cases. The accurate and prompt diagnosis of viral myocarditis is very challenging. Endomyocardial biopsy is considered to be the gold standard test to confirm viral myocarditis; however, it is an invasive procedure, and the sensitivity is low when myocardial involvement is focal. Cardiac imaging hence plays an essential role in the noninvasive evaluation of viral myocarditis. The current coronavirus disease 2019 (COVID-19) pandemic has generated considerable interest in the use of imaging in the early detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-related myocarditis. This article reviews the role of various cardiac imaging modalities used in the diagnosis and assessment of viral myocarditis, including COVID-19-related myocarditis.

BEX1 is a critical determinant of viral myocarditis

Viral infection of the heart is a common but underappreciated cause of heart failure. Viruses can cause direct cardiac damage by lysing infected cardiomyocytes. Inflammatory immune responses that limit viral replication can also indirectly cause damage during infection, making regulatory factors that fine-tune these responses particularly important. Identifying and understanding these factors that regulate cardiac immune responses during infection will be essential for developing targeted treatments for virus-associated heart failure. Our laboratory has discovered Brain Expressed X-linked protein 1 (BEX1) as a novel stress-regulated pro-inflammatory factor in the heart. Here we report that BEX1 plays a cardioprotective role in the heart during viral infection. Specifically, we adopted genetic gain- and loss-of-function strategies to modulate BEX1 expression in the heart in the context of coxsackievirus B3 (CVB3)-induced cardiomyopathy and found that BEX1 limits viral replication in cardiomyocytes. Interestingly, despite the greater viral load observed in mice lacking BEX1, inflammatory immune cell recruitment in the mouse heart was profoundly impaired in the absence of BEX1. Overall, the absence of BEX1 accelerated CVB3-driven heart failure and pathologic heart remodeling. This result suggests that limiting inflammatory cell recruitment has detrimental consequences for the heart during viral infections. Conversely, transgenic mice overexpressing BEX1 in cardiomyocytes revealed the efficacy of BEX1 for counteracting viral replication in the heart in vivo. We also found that BEX1 retains its antiviral role in isolated cells. Indeed, BEX1 was necessary and sufficient to counteract viral replication in both isolated primary cardiomyocytes and mouse embryonic fibroblasts suggesting a broader applicability of BEX1 as antiviral agent that extended to viruses other than CVB3, including Influenza A and Sendai virus. Mechanistically, BEX1 regulated interferon beta (IFN-β) expression in infected cells. Overall, our study suggests a multifaceted role of BEX1 in the cardiac antiviral immune response.

Soluble ST2 Receptor: Biomarker of Left Ventricular Impairment and Functional Status in Patients with Inflammatory Cardiomyopathy

INTRODUCTION

Inflammatory cardiomyopathy (ICM) frequently leads to myocardial fibrosis, resulting in permanent deterioration of the left ventricular function and an unfavorable outcome. Soluble suppression of tumorigenicity 2 receptor (sST2) is a novel marker of inflammation and fibrosis in cardiovascular tissues. sST2 was found to be helpful in predicting adverse outcomes in heart failure patients with reduced ejection fraction. The aim of this study was to determine the association of sST2 plasma levels with cardiac magnetic resonance (CMR) and echocardiography imaging features of left ventricular impairment in ICM patients, as well as to evaluate the applicability of sST2 as a prognosticator of the clinical status in patients suffering from ICM.

METHODS

We used plasma samples of 89 patients presenting to the Heart Center Leipzig with clinically suspected myocardial inflammation. According to immunohistochemical findings in endomyocardial biopsies (EMB) conducted in the context of patients' diagnostic work-up, inflammatory cardiomyopathy was diagnosed in 60 patients (ICM group), and dilated cardiomyopathy in 29 patients (DCM group). All patients underwent cardiac catheterization for exclusion of coronary artery disease and CMR imaging on 1.5 or 3 Tesla. sST2 plasma concentration was determined using ELISA.

RESULTS

Mean plasma concentration of sST2 in the whole patient cohort was 45.8 ± 26.4 ng/mL (IQR 27.5 ng/mL). In both study groups, patients within the highest quartile of sST2 plasma concentration had a significantly lower left ventricular ejection fraction (LV-EF) compared to patients within the lowest sST2 plasma concentration quartile (26 ± 11% vs. 40 ± 13%, p = 0.05 for ICM and 24 ± 13% vs. 51 ± 10%, p = 0.004 for DCM). sST2 predicted New York Heart Association (NYHA) class III/IV at 12 months follow-up more efficiently in ICM compared to DCM patients (AUC 0.85 vs. 0.61, p = 0.02) and was in these terms superior to NT-proBNP and cardiac troponin T. ICM patients with sST2 plasma concentration higher than 44 ng/mL at baseline had a significantly higher probability of being assigned to NYHA class III/IV at 12 months follow-up (hazard ratio 2.8, 95% confidence interval 1.01-7.6, log rank p = 0.05).

CONCLUSION

Plasma sST2 levels in ICM patients reflect the degree of LV functional impairment at hospital admission and predict functional NYHA class at mid-term follow-up. Hence, ST2 may be helpful in the evaluation of disease severity and in the prediction of the clinical status in ICM patients.

Acute perimyocarditis mimicking acute myocardial infarction in a 12-year-old boy with duchenne muscular dystrophy: a case report

Differential diagnosis of chest pain in the pediatric population is important but can be challenging. A 12-year-old boy with Duchenne muscular dystrophy presented with chest pain, cardiac enzyme elevation, and convex ST elevations in the inferior leads with reciprocal ST depression in the anterior leads on electrocardiogram. Echocardiography on admission revealed normal left ventricular function. Suspecting acute myocardial infarction, we performed invasive coronary angiography, which revealed normal coronary arteries. A follow-up electrocardiogram showed an acute pericarditis pattern with concave ST elevations in most leads and PR depression, and follow-up echocardiography revealed global left ventricular dysfunction, suggestive of acute perimyocarditis. Ibuprofen was administered for acute pericarditis, and a continuous milrinone infusion was commenced for myocardial dysfunction. The chest pain improved by the next day, and the ST segment elevations normalized on day 4. Echocardiography on day 9 revealed improved left ventricular function. The patient was discharged on day 11, and he is doing well without chest pain through 12 months of follow-up. The last electrocardiogram showed normal sinus rhythm without ST change. Differential diagnosis of acute myocardial infarction and acute perimyocarditis is important for proper treatment strategies and the different prognoses of these two conditions.

Detection of acute myocarditis using T1 and T2 mapping cardiovascular magnetic resonance: A systematic review and meta-analysis

OBJECTIVES

This study was aimed to systematically review the existing literature and explore more the diagnostic value of T1 and T2 mapping in acute myocarditis.

METHODS

Studies were searched from five electronic databases. Sensitivity, specificity, diagnostic odds ratio (DOR), and summary receiver operating characteristic curves (SROC) were calculated to present diagnostic performance. A meta-regression and subgroup analysis was performed based on validation (endomyocardial biopsy [EMB] vs. clinical criteria).

RESULTS

A total of 10 studies were included, with 400 myocarditis patients and 266 controls. Native T1, T2, and extracellular volume (ECV) values were significantly increased in the myocarditis group. Pooled sensitivities for T1, T2 mapping, and ECV were 0.84 (0.78-0.88), 0.77 (0.69-0.83), and 0.69 (0.50-0.83), respectively. Pooled specificities were 0.86 (0.69-0.95), 0.83 (0.73-0.89), and 0.77 (0.63-0.87), respectively. The DORs were 32 (12-87), 16 (8-30), and 7 (4-14), respectively. The areas under the curve (AUC) of SROC were 0.87 (0.84-0.90), 0.86 (0.82-0.89), and 0.80 (0.76-0.83), respectively. In the meta-regression and subgroup analysis, significantly lower specificities of T1 and T2 mapping were observed in EMB studies (p < 0.01).

CONCLUSION

The currently available evidence shows that T1 and T2 mapping including ECV alone offer comparably good diagnostic performance for the detection of acute myocarditis. The reason for the observed mismatch with EMB findings should be further investigated.

Acute Myocarditis in Children: An Overview of Treatment and Recent Patents

BACKGROUND

Pediatric myocarditis is rare but challenging. This overview summarized the current knowledge and recent patents on childhood myocarditis.

METHODS

Clinical queries and keywords of "myocarditis" and "childhood" were used as search engine.

RESULTS

Viral infections are the most common causes of acute myocarditis. Affected children often have a prodrome of fever, malaise, and myalgia. Clinical manifestations of acute myocarditis in children can be nonspecific. Some children may present with easy fatigability, poor appetite, vomiting, abdominal pain, exercise intolerance, respiratory distress/tachypnea, dyspnea at rest, orthopnea, chronic cough with wheezing, chest pain, unexplained tachycardia, hypotension, syncope, and hepatomegaly. Supraventricular arrhythmias, ventricular arrhythmias, and heart block may be present. A subset of patients have fulminant myocarditis and present with cardiovascular collapse, which may progress to severe cardiogenic shock, and even death. A high index of suspicion is crucial to its diagnosis and timely management. Cardiac magnetic resonance imaging is important in aiding clinical diagnosis while, endomyocardial biopsy remains the gold standard. The treatment consists of supportive therapy, ranging from supplemental oxygen and fluid restriction to mechanical circulatory support. Angiotensinconverting enzyme inhibitors, angio-tensin II receptor blockers, β-blockers, and aldosterone antagonists might be used for the treatment of heart failure while, immunosuppression treatments remain controversial. There are a few recent patents targeting prevention or treatment of viral myocarditis, including an immunogenic composition comprising a PCV-2 antigen, glutathione-S-transferase P1, neuregulins, NF-[kappa] B inhibitor, a pharmaceutical composition which contains 2-amino-2- (2- (4-octyl phenyl) - ethyl) propane 1,3-diol, a composition containing pycnojenol, Chinese herbal concoctions, and a Korean oral rapamycin. Evidence of their efficacy is still lacking.

CONCLUSION

This article reviews the current literature regarding etiology, clinical manifestations, diagnosis, and management of acute myocarditis in children.

Acute myocarditis: aetiology, diagnosis and management

Acute myocarditis is a serious, likely underdiagnosed condition affecting people of all ages and for which the number of UK hospital admissions is rising. A primary diagnosis of myocarditis accounted for 0.04% (36.5 per 100,000) of all hospital admissions in England between 1998 and 2017, although this is likely to be an underestimate of the true burden of myocarditis. The aetiology is broad, including infective and inflammatory conditions as well as exposure to toxic agents. Clinical features are varied and overlap with other acute cardiac conditions making diagnosis a challenge. Cardiovascular magnetic resonance imaging currently serves as the gold standard non-invasive diagnostic modality. If an underlying aetiological process is identified, then therapy may be directed at the cause; however, for most, treatment is supportive and aimed at managing any complications such as heart failure or arrhythmias. There is emerging evidence for immunosuppressive therapy in certain cases. Prognosis is generally good with recovery in most; however, up to 30% with biopsy-proven myocarditis progress to develop a dilated cardiomyopathy and its potential associated complications. All-cause mortality in the UK for patients presenting to hospital with acute myocarditis is approximately 4%.

Diagnosis and Management of Myocarditis: An Evidence-Based Review for the Emergency Medicine Clinician

BACKGROUND

Myocarditis is a potentially fatal condition that can be misdiagnosed in the emergency department (ED) setting.

OBJECTIVE

The purpose of this narrative review article is to provide a summary of the background, pathophysiology, diagnosis, and management of myocarditis, with a focus on emergency clinicians.

DISCUSSION

Myocarditis occurs when inflammation of the heart musculature causes cardiac dysfunction. Symptoms may range from mild to severe and are often preceded by a viral prodrome. Laboratory assessment and an electrocardiogram can be helpful for the diagnosis, but echocardiography is the ideal test in the ED setting. Some patients may also require advanced imaging, though this will often occur during hospitalization or follow-up. Treatment is primarily focused on respiratory and hemodynamic support. Initial hemodynamic management includes vasopressors and inotropes, whereas more severe cases may require an intra-aortic balloon pump, extracorporeal membrane oxygenation, or a ventricular assist device. Nonsteroidal anti-inflammatory drugs should be avoided while intravenous immunoglobulin is controversial.

CONCLUSION

Myocarditis is a serious condition with the potential for significant morbidity and mortality. It is important for clinicians to be aware of the current evidence regarding the diagnosis, management, and disposition of these patients.

COVID-19 multisystemic inflammatory syndrome in adults: a not to be missed diagnosis

We report COVID-19 multisystemic inflammatory syndrome in an adult patient with an atypical presentation (mild abdominal pain) and a negative (repeated) reverse transcriptase-PCR, in the absence of lung involvement on lung ultrasound. In this case, focused cardiac ultrasound revealed signs of myopericarditis and enabled us to focus on the problem that was putting our patient in a perilous situation, with a quick, non-time-consuming and easy-to-access technique. Serology test was performed and SARS-CoV-2 infection was confirmed more than a week after admission to the coronary unit. As the patient had a general good appearance, the potential implications of missing this diagnosis could have been fatal.

Malaria and the Heart: JACC State-of-the-Art Review

As one of the tropical diseases, malaria is endemic in developing countries. Severe malaria, mainly caused by the Plasmodium falciparum parasite, can result in life-threatening complications. Traditionally, cardiac involvement has not been included as a frequent cause of morbidity and mortality. This could be due to under-reporting or underdiagnosing. Specific cardiovascular (CV) complications include electrocardiogram abnormalities, myocarditis, pericarditis, pericardial effusion, ischemic disease, and heart failure. According to the data analyzed, CV manifestations can lead to severe consequences. Possible theories related to the pathophysiological mechanisms related to CV compromise include an imbalanced pro-inflammatory cytokine response and/or erythrocyte sequestration by increased cytoadherence to endothelium. Although there is a paucity of data regarding cardiac manifestations of malaria, an algorithm for appropriate use of diagnostic tools to assess cardiac involvement has been developed in this paper. Furthermore, it is important to note that typical antimalarial treatment regimens can have fatal cardiac side-effects.

Effects of statins on myocarditis: A review of underlying molecular mechanisms

Myocarditis refers to the clinical and histological characteristics of a diverse range of inflammatory cellular pathophysiological conditions which result in cardiac dysfunction. Myocarditis is a major cause of mortality in individuals less than 40 years of age and accounts for approximately 20% of cardiovascular disease (CVD) events. Myocarditis contributes to dilated cardiomyopathy in 30% of patients and can progress to cardiac arrest, which has a poor prognosis of <40% survival over 10 years. Myocarditis has also been documented after infection with SARS-CoV-2. The most commonly used lipid-lowering therapies, HMG-CoA reductase inhibitors (statins), decrease CVD-related morbidity and mortality. In addition to their lipid-lowering effects, increasing evidence supports the existence of several additional beneficial, 'pleiotropic' effects of statins. Recently, several studies have indicated that statins may attenuate myocarditis. Statins modify the lipid oxidation, inflammation, immunomodulation, and endothelial activity of the pathophysiology and have been recommended as adjuvant treatment. In this review, we focus on the mechanisms of action of statins and their effects on myocarditis, SARS-CoV-2 and CVD.

Vagus nerve plays a pivotal role in CD4+ T cell differentiation during CVB3-induced murine acute myocarditis

Abnormalities in CD4⁺ T cell (Th cell) differentiation play an important role in the pathogenesis of viral myocarditis (VMC). Our previous studies demonstrated that activation of the cholinergic anti-inflammatory pathway (CAP) alleviated the inflammatory response. In addition, we observed that right cervical vagotomy aggravates VMC by inhibiting CAP. However, the vagus nerve’s effect on differentiation of CD4⁺ T cells has not been studied in VMC mice to date. In this study, we investigated the effects of cervical vagotomy and the α7nAChR agonist pnu282987 on CD4⁺ T cell differentiation in a murine myocarditis model (BALB/c) infected with coxsackievirus B3 (CVB3). Splenic CD4⁺ T cells from CVB3-induced mice obtained and cultured to investigate the potential mechanism of CD4⁺ T cell differentiation. Each Th cell subset was analyzed by flow cytometry. Our results showed that right cervical vagotomy increased proportions of Th1 and Th17 cells and decreased proportions of Th2 and Treg cells in the spleen. Vagotomy-induced upregulation of T-bet, Ror-γ, IFN-γ, and IL-17 expression while downregulating the expression of Gata3, Foxp3, and IL-4 in the heart. In addition, we observed upregulated levels of proinflammatory cytokines, aggravated myocardial lesions and cellular infiltration, and worsened cardiac function in VMC mice. Pnu282987 administration reversed these outcomes. Furthermore, vagotomy inhibited JAK2-STAT3 activation and enhanced NF-κB activation in splenic CD4⁺ T cells. The CD4⁺ T cell differentiation was related to JAK2-STAT3 and NF-κB signal pathways. In conclusion, vagus nerve modulates the inflammatory response by regulating CD4⁺ T cell differentiation in response to VMC.

MicroRNA-30a Modulates Type I Interferon Responses to Facilitate Coxsackievirus B3 Replication Via Targeting Tripartite Motif Protein 25

Viral myocarditis is caused by a viral infection and characterized by the inflammation of the myocardium. Coxsackievirus B3 (CVB3) infection is one of the most common among the infections caused by this virus. The host's early innate immune response to CVB3 infection particularly depends on the functions of type I interferons (IFNs). In this study, we report that a host microRNA, miR-30a, was upregulated by CVB3 to facilitate its replication. We demonstrated that miR-30a was a potent negative regulator of IFN-I signaling by targeting tripartite motif protein 25 (TRIM25). In addition, we found that TRIM25 overexpression significantly suppressed CVB3 replication, whereas TRIM25 knockdown increased viral titer and VP1 protein expression. MiR-30a inhibits the expression of TRIM25 and TRIM25-mediated retinoic acid-inducible gene (RIG)-I ubiquitination to suppress IFN-β activation and production, thereby resulting in the enhancement of CVB3 replication. These results indicate the proviral role of miR-30a in modulating CVB3 infection for the first time. This not only provides a new strategy followed by CVB3 in order to modulate IFN-I-mediated antiviral immune responses by engaging host miR-30a but also improves our understanding of its pathogenesis.

Cardiogenic Shock Induced by Anterior Pituitary Hypofunction and Thyrotoxicosis

Cardiogenic shock occurs when the heart is unable to pump enough blood for the needs of the body. Hypopituitarism is a condition in which the pituitary gland does not produce enough of one or more hormones, and it rarely occurs with thyrotoxicosis. We report a rare case of cardiogenic shock induced by anterior pituitary hypofunction and thyrotoxicosis. A 47-year-old woman was admitted twice to the hospital due to generalized worsening muscle pain for 13 days, and accompanied by a transient loss of consciousness. Cardiogenic shock developed during hospitalization, which improved with active resuscitative measures. Laboratory tests showed thyrotoxicosis. Pituitary magnetic resonance imaging (MRI) and relevant hormone tests confirmed anterior pituitary hypofunction. The patient was given hormone replacement therapy, which stabilized her condition. We believe cardiogenic shock may be a serious complication of hypopituitarism. We recommend establishing an expert system (ES) to facilitate the early diagnosis and treatment of cardiogenic shock, improve the professional skills of primary care physicians, and optimize treatment plans.

Effect of Acute Immunosuppression on Left Ventricular Recovery and Mortality in Fulminant Viral Myocarditis: A Case Series and Review of Literature

Background

Fulminant viral myocarditis (FVM) is a rare cause of cardiogenic shock associated with high morbidity and mortality rates. An inappropriately activated immune system results in severe myocardial inflammation. Acute immunosuppressive therapy for FVM therefore gained in popularity and was described in numerous retrospective studies.

Methods

We conducted an extensive review of the literature and compared it with our single-centre retrospective review of all cases of FVM from 2009-2019 to evaluate the possible effect of acute immunosuppression with intravenous immunoglobulins and/or high dose corticosteroids in patients with FVM.

Results

We report on 17 patients with a mean age of 46 ± 15 years with a mean left ventricular ejection fraction (LVEF) of 15 ± 9% at admission. Fourteen (82%) of our patients had acute LVEF recovery to ≥ 45% after a mean time from immunosuppression of 74 ± 49 hours (3.1 days). Extracorporeal membrane oxygenation (ECMO) was required in 35% (6/17) of our patients for an average support of 126 ± 37 hours. Overall mortality was 12% (2/17). No patient needed a long-term left ventricular assist device or heart transplant. All surviving patients achieved complete long-term LVEF recovery.

Conclusions

Our cohort of 17 severely ill patients received acute immunosuppressive therapy and showed a rapid LVEF recovery, short duration of ECMO support, and low mortality rate. Our suggested scheme of investigation and treatment is presented. These results bring more cases of successfully treated FVM with immunosuppression and ECMO to the literature, which might stimulate further prospective trials or a registry.

Weighted gene co-expression network analysis identified underlying hub genes and mechanisms in the occurrence and development of viral myocarditis

Background

Myocarditis is an inflammatory myocardial disease, which may lead to heart failure and sudden death. Despite extensive research into the pathogenesis of myocarditis, effective treatments for this condition remain elusive. This study aimed to explore the potential pathogenesis and hub genes for viral myocarditis.

Methods

A weighted gene co-expression network analysis (WGCNA) was performed based on the gene expression profiles derived from mouse models at different stages of viral myocarditis (GSE35182). Functional annotation was executed within the key modules. Potential hub genes were predicted based on the intramodular connectivity (IC). Finally, potential microRNAs that regulate gene expression were predicted by miRNet analysis.

Results

Three gene co-expression modules showed the strongest correlation with the acute or chronic disease stage. A significant positive correlation was detected between the acute disease stage and the turquoise module, the genes of which were mainly enriched in antiviral response and immune-inflammatory activation. Furthermore, a significant positive correlation and a negative correlation were identified between the chronic disease stage and the brown and yellow modules, respectively. These modules were mainly associated with the cytoskeleton, phosphorylation, cellular catabolic process, and autophagy. Subsequently, we predicted the underlying hub genes and microRNAs in the three modules.

Conclusions

This study revealed the main biological processes in different stages of viral myocarditis and predicted hub genes in both the acute and chronic disease stages. Our results may be helpful for developing new therapeutic targets for viral myocarditis in future research.

Myocarditis: imaging up to date

Myocarditis is an inflammatory disease of the heart muscle, diagnosed by histological, immunological, and immunohistochemical criteria. Endomyocardial biopsy represents the diagnostic gold standard for its diagnosis but is infrequently used. Due to its noninvasive ability to detect the presence of myocardial edema, hyperemia and necrosis/fibrosis, Cardiac MR imaging is routinely used in the clinical practice for the diagnosis of acute myocarditis. Recently pixel-wise mapping of T1 and T2 relaxation time have been introduced into the clinical Cardiac MR protocol increasing its accuracy. Our paper will review the role of MR imaging in the diagnosis of acute myocarditis.

Long non-coding RNA MEG3 inhibits M2 macrophage polarization by activating TRAF6 via microRNA-223 down-regulation in viral myocarditis

Viral myocarditis (VMC) commonly triggers heart failure, for which no specific treatments are available. This study aims to explore the specific role of long non‐coding RNA (lncRNA) maternally expressed 3 (MEG3) in VMC. A VMC mouse model was induced by Coxsackievirus B3 (CVB3). Then, MEG3 and TNF receptor‐associated factor 6 (TRAF6) were silenced and microRNA‐223 (miR‐223) was over‐expressed in the VMC mice, followed by determination of ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS). Dual‐luciferase reporter assay was introduced to test the interaction among MEG3, TRAF6 and miR‐223. Macrophages were isolated from cardiac tissues and bone marrow, and polarization of M1 or M2 macrophages was induced. Then, the expressions of components of NLRP3 inflammatory body (NLRP3, ASC, Caspase‐1), M1 markers (CD86, iNOS and TNF‐α) and M2 markers (CD206, Arginase‐1 and Fizz‐1) were measured following MEG3 silencing. In the VMC mouse model, MEG3 and TRAF6 levels were obviously increased, while miR‐223 expression was significantly reduced. Down‐regulation of MEG3 resulted in the inhibition of TRAF6 by promoting miR‐223. TRAF6 was negatively correlated with miR‐223, but positively correlated with MEG3 expression. Down‐regulations of MEG3 or TRAF6 or up‐regulation of miR‐223 was observed to increase mouse weight, survival rate, LVEF and LVFS, while inhibiting myocarditis and inflammation via the NF‐κB pathway inactivation in VMC mice. Down‐regulation of MEG3 decreased M1 macrophage polarization and elevated M2 macrophage polarization by up‐regulating miR‐223. Collectively, down‐regulation of MEG3 leads to the inhibition of inflammation and induces M2 macrophage polarization via miR‐223/TRAF6/NF‐κB axis, thus alleviating VMC.

Cardiac Involvement in a Patient With Coronavirus Disease 2019 (COVID-19)

Importance

Virus infection has been widely described as one of the most common causes of myocarditis. However, less is known about the cardiac involvement as a complication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

Objective

To describe the presentation of acute myocardial inflammation in a patient with coronavirus disease 2019 (COVID-19) who recovered from the influenzalike syndrome and developed fatigue and signs and symptoms of heart failure a week after upper respiratory tract symptoms.

Design, Setting, and Participant

This case report describes an otherwise healthy 53-year-old woman who tested positive for COVID-19 and was admitted to the cardiac care unit in March 2020 for acute myopericarditis with systolic dysfunction, confirmed on cardiac magnetic resonance imaging, the week after onset of fever and dry cough due to COVID-19. The patient did not show any respiratory involvement during the clinical course.

Exposure

Cardiac involvement with COVID-19.

Main Outcomes and Measures

Detection of cardiac involvement with an increase in levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) and high-sensitivity troponin T, echocardiography changes, and diffuse biventricular myocardial edema and late gadolinium enhancement on cardiac magnetic resonance imaging.

Results

An otherwise healthy 53-year-old white woman presented to the emergency department with severe fatigue. She described fever and dry cough the week before. She was afebrile but hypotensive; electrocardiography showed diffuse ST elevation, and elevated high-sensitivity troponin T and NT-proBNP levels were detected. Findings on chest radiography were normal. There was no evidence of obstructive coronary disease on coronary angiography. Based on the COVID-19 outbreak, a nasopharyngeal swab was performed, with a positive result for SARS-CoV-2 on real-time reverse transcriptase-polymerase chain reaction assay. Cardiac magnetic resonance imaging showed increased wall thickness with diffuse biventricular hypokinesis, especially in the apical segments, and severe left ventricular dysfunction (left ventricular ejection fraction of 35%). Short tau inversion recovery and T2-mapping sequences showed marked biventricular myocardial interstitial edema, and there was also diffuse late gadolinium enhancement involving the entire biventricular wall. There was a circumferential pericardial effusion that was most notable around the right cardiac chambers. These findings were all consistent with acute myopericarditis. She was treated with dobutamine, antiviral drugs (lopinavir/ritonavir), steroids, chloroquine, and medical treatment for heart failure, with progressive clinical and instrumental stabilization.

Conclusions and Relevance

This case highlights cardiac involvement as a complication associated with COVID-19, even without symptoms and signs of interstitial pneumonia.