Immunosuppressive therapy in acute myocarditis: an 18 year systematic review

Endosomal Toll-Like Receptors intermediate negative impacts of viral diseases, autoimmune diseases, and inflammatory immune responses on the cardiovascular system

INTRODUCTION

Cardiovascular disease (CVD) is the leading cause of morbidity globally, with chronic inflammation as a key modifiable risk factor. Toll-like receptors (TLRs), pivotal components of the innate immune system, including TLR-3, -7, -8, and -9 within endosomes, trigger intracellular cascades, leading to inflammatory cytokine production by various cell types, contributing to systemic inflammation and atherosclerosis. Recent research highlights the role of endosomal TLRs in recognizing self-derived nucleic acids during sterile inflammation, implicated in autoimmune conditions like myocarditis.

AREAS COVERED

This review explores the impact of endosomal TLRs on viral infections, autoimmunity, and inflammatory responses, shedding light on their intricate involvement in cardiovascular health and disease by examining literature on TLR-mediated mechanisms and their roles in CVD pathophysiology.

EXPERT OPINION

Removal of endosomal TLRs mitigates myocardial damage and immune reactions, applicable in myocardial injury. Targeting TLRs with agonists enhances innate immunity against fatal viruses, lowering viral loads and mortality. Prophylactic TLR agonist administration upregulates TLRs, protecting against fatal viruses and improving survival. TLRs play a complex role in CVDs like atherosclerosis and myocarditis, with therapeutic potential in modulating TLR reactions for cardiovascular health.

The Molecular Role of Immune Cells in Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) is a rare and severe condition characterized by chamber dilation and impaired contraction of the left ventricle. It constitutes a fundamental etiology for profound heart failure and abrupt cardiac demise, rendering it a prominent clinical indication for heart transplantation (HTx) among both adult and pediatric populations. DCM arises from various etiologies, including genetic variants, epigenetic disorders, infectious insults, autoimmune diseases, and cardiac conduction abnormalities. The maintenance of cardiac function involves two distinct types of immune cells: resident immune cells and recruited immune cells. Resident immune cells play a crucial role in establishing a harmonious microenvironment within the cardiac tissue. Nevertheless, in response to injury, cardiomyocytes initiate a cytokine cascade that attracts peripheral immune cells, thus perturbing this intricate equilibrium and actively participating in the initiation and pathological remodeling of dilated cardiomyopathy (DCM), particularly during the progression of myocardial fibrosis. Additionally, immune cells assume a pivotal role in orchestrating the inflammatory processes, which are intimately linked to the prognosis of DCM. Consequently, understanding the molecular role of various immune cells and their regulation mechanisms would provide an emerging era for managing DCM. In this review, we provide a summary of the most recent advancements in our understanding of the molecular mechanisms of immune cells in DCM. Additionally, we evaluate the effectiveness and limitations of immunotherapy approaches for the treatment of DCM, with the aim of optimizing future immunotherapeutic strategies for this condition.

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.

Update on COVID-19 Myocarditis

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) gained worldwide attention at the end of 2019 when it was identified to cause severe respiratory distress syndrome. While it primarily affects the respiratory system, we now have evidence that it affects multiple organ systems in the human body. Cardiac manifestations may include myocarditis, life threatening arrhythmias, acute coronary syndrome, systolic heart failure, and cardiogenic shock. Myocarditis is increasingly recognized as a complication of Coronavirus-19 (COVID-19) and may result from direct viral injury or from exaggerated host immune response. The diagnosis is established similar to other etiologies, and is based on detailed history, clinical exam, laboratory findings and non-invasive imaging studies. When available, cardiac MRI is the preferred imaging modality. Endomyocardial biopsy may be performed if the diagnosis remains uncertain. Current management is mainly supportive with the potential addition of interventions recommended for severe COVID-19 disease, such as remdesivir, steroids, and convalescent plasma. In the setting of cardiogenic shock and refractory, life-threatening arrhythmias that persist despite medical therapy, advanced mechanical circulatory support devices should be considered. Ultimately, early recognition and aggressive intervention are key factors in reducing morbidity and mortality. Our management strategy is expected to evolve further as we learn more about COVID-19 disease and the associated cardiac complications.

Acute Myocarditis in Children: a 10-year Nationwide Study (2007-2016) based on the Health Insurance Review and Assessment Service Database in Korea

BACKGROUND AND OBJECTIVES

We performed a nationwide study to assess the incidence, treatment patterns, and outcomes of acute myocarditis in Korean children.

METHODS

The nationwide incidence, treatment patterns, and outcomes of acute myocarditis in Korean children were assessed using data between 2007 and 2016 from the Health Insurance Review and Assessment database.

RESULTS

We investigated 1,627 children during the study period. The overall incidence of acute myocarditis was 1.4 per 100,000 children in 2007 and 2.1 per 100,000 children in 2016, which indicates a significant increase in the trend over time. A bimodal age distribution was observed with a larger peak in infancy and a smaller peak in the mid-teenage years. No sex difference was observed in the incidence rate of acute myocarditis in children aged ≤5 years (373 boys vs. 366 girls); however, the incidence rate of acute myocarditis in adolescents aged ≥13 years showed significant male preponderance (482 boys vs. 152 girls). Acute fulminant myocarditis occurred in 371 children (22.8%) who needed extracorporeal membrane oxygenation and/or mechanical ventilator support. Of the 371 children with acute fulminant myocarditis, 258 (69.5%) survived. The survival rate of children with acute fulminant myocarditis remained nearly identical over the 10-year study period.

CONCLUSIONS

This was the first nationwide epidemiological study to investigate acute myocarditis in Korean children. In our view, this study would help clinicians in decision-making and planning for optimal management of acute myocarditis in children.

The forkhead transcription factor Foxo3 negatively regulates natural killer cell function and viral clearance in myocarditis

Aims

Foxo3 is a transcription factor involved in cell metabolism, survival, and inflammatory disease. However, mechanistic insight in Foxo3 effects is still limited. Here, we investigated the role of Foxo3 on natural killer (NK) cell responses and its effects in viral myocarditis.

Methods and results

Effects of Foxo3 on viral load and immune responses were investigated in a model of coxsackie virus B3 myocarditis in wild-type (WT) and Foxo3 deficient mice. Reduced immune cell infiltration, viral titres, and pro-inflammatory cytokines in cardiac tissue were observed in Foxo3-/- mice 7 days post-infection (p.i.). Viral titres were also attenuated in hearts of Foxo3-/- mice at Day 3 while interferon-γ (IFNγ) and NKp46 expression were up-regulated suggesting early viral control by enhanced NK cell activity. CD69 expression of NK cells, frequencies of CD11b+CD27+ effector NK cells and cytotoxicity of Foxo3-/- mice was enhanced compared to WT littermates. Moreover, microRNA-155 expression, essential in NK cell activation, was elevated in Foxo3-/- NK cells while its inhibition led to diminished IFNγ production. Healthy humans carrying the longevity-associated FOXO3 single nucleotide polymorphism (SNP) rs12212067 exhibited reduced IFNγ and cytotoxic degranulation of NK cells. Viral inflammatory cardiomyopathy (viral CMI) patients with this SNP showed a poorer outcome due to less efficient virus control.

Conclusion

Our results implicate Foxo3 in regulating NK cell function and suggest Foxo3 playing an important role in the antiviral innate immunity. Thus, enhanced FOXO3 activity such as in the polymorphism rs12212067 may be protective in chronic inflammation such as cancer and cardiovascular disease but disadvantageous to control acute viral infection.

Role of intravenous immunoglobulin therapy in the survival rate of pediatric patients with acute myocarditis: A systematic review and meta-analysis

The treatment of pediatric myocarditis is controversial, and the benefits of intravenous immunoglobulin (IVIG) are inconclusive due to limited data. We searched studies from PubMed, MEDLINE, Embase, and Cochrane Library databases since establishment until October 1st, 2018. Thirteen studies met the inclusion criteria. We included a total of 812 patients with IVIG treatment and 592 patients without IVIG treatment. The meta-analysis showed that the survival rate in the IVIG group was higher than that in the non-IVIG group (odds ratio = 2.133, 95% confidence interval (CI): 1.32-3.43, p = 0.002). There was moderate statistical heterogeneity among the included studies (I² = 35%, p = 0.102). However, after adjustment using Duval and Tweedie's trim and fill method, the point estimate of the overall effect size was 1.40 (95% CI 0.83, 2.35), which became insignificant. Moreover, the meta-regression revealed that age (coefficient = -0.191, 95% CI (-0.398, 0.015), p = 0.069) and gender (coefficient = 0.347, 95% CI (-7.586, 8.279), p = 0.93) were not significantly related to the survival rate. This meta-analysis showed that IVIG treatment was not associated with better survival. The use of IVIG therapy in acute myocarditis in children cannot be routinely recommended based on current evidence. Further prospective and randomized controlled studies are needed to elucidate the effects of IVIG treatment.

The Diagnostic and Clinical Approach to Pediatric Myocarditis: A Review of the Current Literature

Myocarditis is an inflammatory disease of the myocardium with a broad spectrum of clinical presentations, ranging from mild symptoms to severe heart failure. The course of patients with myocarditis is heterogeneous, varying from partial or full clinical recovery in a few days to advanced low cardiac output syndrome requiring mechanical circulatory support or heart transplantation. Myocarditis is a very heterogeneous disease, especially in the pediatric age group as worldwide disease myocarditis has been defined by the World Health Organization/International Society and Federation of Cardiology as an inflammatory disease of the heart muscle diagnosed by established histological, immunologic, and immunohistological criteria. Pediatric myocarditis remains challenging from the perspectives of diagnosis and management. Multiple etiologies exist, and the majority of cases appear to be related to viral illnesses. Enteroviruses are believed to be the most common cause, although cases related to adenovirus may be more frequent than suspected. The clinical presentation is extremely varied, ranging from asymptomatic to sudden unexpected death. A high index of suspicion is crucial. There is emerging evidence to support investigations such as serum N-terminal B-type natriuretic peptide levels, as well as cardiac magnetic resonance imaging as adjuncts to the clinical diagnosis. In the future, these may reduce the necessity for invasive methods, such as endomyocardial biopsy, which remain the gold standard. Management generally includes supportive care, consisting of cardiac failure medical management, with the potential for mechanical support and cardiac transplantation. Treatments aimed at immunosuppression remain controversial. The paediatrics literature is extremely limited with no conclusive evidence to support or refute these strategies. All these summarised in this article and the listed current literature showed that there is no consensus regarding aetiology, clinical presentation, diagnosis, and management of myocarditis in pediatric patients.

In-hospital and post-discharge outcomes of pediatric acute myocarditis underwent after high-dose steroid or intravenous immunoglobulin therapy

Background

High-dose steroids and intravenous immunoglobulin (IVIG) are controversial treatments for pediatric patients with acute myocarditis. This study aimed to investigate their efficacies in the Taiwanese pediatric population.

Methods

This study evaluated 5563 acute myocarditis patients from the Taiwan’s National Health Insurance Research Database and identified 1542 pediatric patients hospitalized for acute myocarditis between January 1, 2001 and December 31, 2011. The exclusion criteria were age of > 11 years, associated cardiovascular comorbidities, autoimmune disease, malignancy before the index hospitalization, extracorporeal membrane oxygenation, intra-aortic balloon pumping, and dual therapy using IVIG and high-dose steroids.

Results

After 2:1 propensity score matching, we identified 208 subjects without steroid therapy and 104 subjects who received high-dose steroids. The mean age in that cohort was 2.6 ± 2.9 years, and high-dose steroid therapy had no significant effects on major in-hospital complications and post-discharge outcomes. After 2:1 propensity score matching, we identified 178 subjects without IVIG therapy and 89 subjects who received IVIG. The mean age in that cohort was 2.0 ± 2.1 years, and IVIG had no significant effects on the major outcomes.

Conclusions

The present study revealed that high-dose steroid or IVIG therapy had no significant effects on major in-hospital complications, late heart failure hospitalization, and long-term mortality.

The Diagnostic and Clinical Approach to Pediatric Myocarditis: A Review of the Current Literature

Myocarditis is an inflammatory disease of the myocardium with a broad spectrum of clinical presentations, ranging from mild symptoms to severe heart failure. The course of patients with myocarditis is heterogeneous, varying from partial or full clinical recovery in a few days to advanced low cardiac output syndrome requiring mechanical circulatory support or heart transplantation. Myocarditis is a very heterogeneous disease, especially in the pediatric age group as worldwide disease myocarditis has been defined by the World Health Organization/International Society and Federation of Cardiology as an inflammatory disease of the heart muscle diagnosed by established histological, immunologic, and immunohistological criteria. Pediatric myocarditis remains challenging from the perspectives of diagnosis and management. Multiple etiologies exist, and the majority of cases appear to be related to viral illnesses. Enteroviruses are believed to be the most common cause, although cases related to adenovirus may be more frequent than suspected. The clinical presentation is extremely varied, ranging from asymptomatic to sudden unexpected death. A high index of suspicion is crucial. There is emerging evidence to support investigations such as serum N-terminal B-type natriuretic peptide levels, as well as cardiac magnetic resonance imaging as adjuncts to the clinical diagnosis. In the future, these may reduce the necessity for invasive methods, such as endomyocardial biopsy, which remain the gold standard. Management generally includes supportive care, consisting of cardiac failure medical management, with the potential for mechanical support and cardiac transplantation. Treatments aimed at immunosuppression remain controversial. The paediatrics literature is extremely limited with no conclusive evidence to support or refute these strategies. All these summarised in this article and the listed current literature showed that there is no consensus regarding aetiology, clinical presentation, diagnosis, and management of myocarditis in pediatric patients.

Aptamers: novelty tools for cancer biology

Although the term ‘cancer’ was still over two thousand years away of being coined, the first known cases of the disease date back to about 3000BC, in ancient Egypt. Five thousand years later, still lacking a cure, it has become one of the leading causes of death, killing over half a dozen million people yearly. So far, monoclonal antibodies are the most successful immune-therapy tools when it comes to fighting cancer. The number of clinical trials that use them has been increasing steadily during the past few years, especially since the Food and Drug Administration greenlit the use of the first immune-checkpoint blockade antibodies. However, albeit successful, this approach does come with the cost of auto-inflammatory toxicity. Taking this into account, the development of new therapeutic reagents with low toxicity becomes evident, particularly ones acting in tandem with the tools currently at our disposal. Ever since its discovery in the early nineties, aptamer technology has been used for a wide range of diagnostic and therapeutic applications. With similar properties to those of monoclonal antibodies, such as high-specificity of recognition and high-affinity binding, and the advantages of being developed using in vitro selection procedures, aptamers quickly became convenient building blocks for the generation of multifunctional constructs. In this review, we discuss the steps involved in the in vitro selection process that leads to functional aptamers - known as Systematic Evolution of Ligands by Exponential Enrichment - as well as the most recent applications of this technology in diagnostic and treatment of oncological illnesses. Moreover, we also suggest ways to improve such use.

The neuropeptide cortistatin attenuates experimental autoimmune myocarditis via inhibition of cardiomyogenic T cell-driven inflammatory responses

BACKGROUND AND PURPOSE

Myocarditis is an inflammatory and autoimmune cardiovascular disease that causes dilated myocardiopathy and is responsible for high morbidity and mortality worldwide. Cortistatin is a neuropeptide produced by neurons and cells of the immune and vascular systems. Besides its action in locomotor activity and sleep, cortistatin inhibits inflammation in different experimental models of autoimmune diseases. However, its role in inflammatory cardiovascular disorders is unexplored. Here, we investigated the therapeutic effects of cortistatin in a well-established preclinical model of experimental autoimmune myocarditis (EAM).

EXPERIMENTAL APPROACH

We induced EAM by immunization with a fragment of cardiac myosin in susceptible Balb/c mice. Cortistatin was administered i.p. starting 7, 11 or 15 days after EAM induction. At day 21, we evaluated heart hypertrophy, myocardial injury, cardiac inflammatory infiltration and levels of serum and cardiac inflammatory cytokines, cortistatin and autoantibodies. We determined proliferation and cytokine production by heart draining lymph node cells in response to cardiac myosin restimulation.

KEY RESULTS

Systemic injection of cortistatin during the effector phase of the disease significantly reduced its prevalence and signs of heart hypertrophy and injury (decreased the levels of brain natriuretic peptide) and impaired myocardial inflammatory cell infiltration. This effect was accompanied by a reduction in self-antigen-specific T-cell responses in lymph nodes and in the levels of cardiomyogenic antibodies and inflammatory cytokines in serum and myocardium. Finally, we found a positive correlation between cardiac and systemic cortistatin levels and EAM severity.

CONCLUSIONS AND IMPLICATIONS

Cortistatin emerges as a new candidate to treat inflammatory dilated cardiomyopathy.

Myocarditis in Paediatric Patients: Unveiling the Progression to Dilated Cardiomyopathy and Heart Failure

Myocarditis is a challenging and potentially life-threatening disease associated with high morbidity in some paediatric patients, due to its ability to present as an acute and fulminant disease and to ultimately progress to dilated cardiomyopathy. It has been described as an inflammatory disease of the myocardium caused by diverse aetiologies. Viral infection is the most frequent cause of myocarditis in developed countries, but bacterial and protozoal infections or drug hypersensitivity may also be causative agents. The prompt diagnosis in paediatric patients is difficult, as the spectrum of clinical manifestation can range from no myocardial dysfunction to sudden cardiac death. Recent studies on myocarditis pathogenesis have revealed a triphasic nature of this disease, which influences the diagnostic and therapeutic strategies to adopt in each patient. Endomyocardial biopsy remains the gold standard for diagnosing myocarditis, and several non-invasive diagnostic tools can be used to support the diagnosis. Intravenous immunoglobulin has become part of routine practice in the treatment of myocarditis in paediatric patients at many centres, but its true effect on the cardiac function has been the target of many studies. The aim of this review is to approach the recently discovered facets of paediatric myocarditis regarding its progression to dilated cardiomyopathy.

Experts' recommendations for the management of cardiogenic shock in children

Cardiogenic shock which corresponds to an acute state of circulatory failure due to impairment of myocardial contractility is a very rare disease in children, even more than in adults. To date, no international recommendations regarding its management in critically ill children are available. An experts’ recommendations in adult population have recently been made (Levy et al. Ann Intensive Care 5(1):52, 2015; Levy et al. Ann Intensive Care 5(1):26, 2015). We present herein recommendations for the management of cardiogenic shock in children, developed with the grading of recommendations’ assessment, development, and evaluation system by an expert group of the Groupe Francophone de Réanimation et Urgences Pédiatriques (French Group for Pediatric Intensive Care and Emergencies). The recommendations cover four major fields of application such as: recognition of early signs of shock and the patient pathway, management principles and therapeutic goals, monitoring hemodynamic and biological variables, and circulatory support (indications, techniques, organization, and transfer criteria). Major principle care for children with cardiogenic shock is primarily based on clinical and echocardiographic assessment. There are few drugs reported as effective in childhood in the medical literature. The use of circulatory support should be facilitated in terms of organization and reflected in the centers that support these children. Children with cardiogenic shock are vulnerable and should be followed regularly by intensivist cardiologists and pediatricians. The experts emphasize the multidisciplinary nature of management of children with cardiogenic shock and the importance of effective communication between emergency medical assistance teams (SAMU), mobile pediatric emergency units (SMUR), pediatric emergency departments, pediatric cardiology and cardiac surgery departments, and pediatric intensive care units.

Acute myocarditis mimicking ST-elevation myocardial infarction: A case report and review of the literature

The present study describes the case of a young man aged 22 who had acute retrosternal pain, elevated cardiac markers and electrocardiographic ST-T changes, which led to an original misdiagnosis of acute myocardial infarction. The patient underwent immediate coronary angiography, which revealed normal coronary arteries. Finally, the diagnosis of viral myocarditis was made on consideration of his fever, scattered red dots on his arms and legs and other auxiliary examination results obtained in the following days, which were supportive of the diagnosis. The patient improved on antiviral and myocardial protection therapy and was discharged 2 weeks later. Viral myocarditis is a common disease with a variable natural history. It remains challenging for doctors to differentiate between acute myocarditis and myocardial infarction, particularly in the early stages. A diagnosis of myocarditis should be made on the basis of synthetic evaluation of the evidence, including medical history, clinical presentation and results of the available auxiliary tests, in order to provide guidelines for treatment.

[Invasive neonatal enterovirus infection involving severe myocarditis and meningitis: report of a case]

L'infection néonatale invasive à entérovirus (EV) reste rare mais souvent fatale et devrait être prise dans le diagnostic différentiel chez les enfants septiques. Nous rapportons le cas d'un nouveau-né hospitalisé pour un sepsis grave à EV avec une méningite et une myocardite sévère d'évolution favorable après une corticothérapie. Nous présentons une discussion basée sur une revue de la littérature pour aider le clinicien à reconnaitre les facteurs de gravité et à apprécier les nouvelles stratégies diagnostiques telle la PCR (Polymerase Chain Reaction) et l'imagerie par résonance magnétique (IRM) cardiaque. Nous passons également en revue les nouvelles approches thérapeutiques telles les biothérapies, les antiviraux spécifiques et l'Oxygénation par Membrane Extra-Corporelle (ECMO).

Corticosteroids for viral myocarditis

BACKGROUND

Myocarditis is defined as inflammation of the myocardium accompanied by myocellular necrosis. Experimental evidence suggests that autoimmune mechanisms follow viral infection, resulting in inflammation and necrosis in the myocardium. However, the use of corticosteroids as immunosuppressives for this condition remains controversial.

OBJECTIVES

The existing review was updated. The primary objective of this review is to assess the beneficial and harmful effects of treating acute or chronic viral myocarditis with corticosteroids. The secondary objective is to determine the best dose regimen.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 7 of 12, 2012) on The Cochrane Library, MEDLINE OVID (1946 to July Week 2, 2012), EMBASE OVID (1980 to Week 29, 2012), BIOSIS Previews (1969 to 20 July 2012), ISI Web of Science (1970 to 20th July, 2012), and LILACS (from its inception to 25 July, 2012) , Chinese Biomed Database, CNKI and WANFANG Databases (from their inception to 31 December 2012). We applied no language restrictions.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of corticosteroids for viral myocarditis compared with no intervention, placebo, supportive therapy, antiviral agents therapy or conventional therapy, including trials of corticosteroids plus other treatment versus other treatment alone, irrespective of blinding, publication status, or language.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data independently. Results were presented as risk ratios (RRs) and mean differences (MDs), both with 95% confidence intervals (CIs).

MAIN RESULTS

Eight RCTs (with 719 participants) were included in this update. The trials were small in size and methodological quality was poor. Viral detection was performed in 38% of participants, among whom 56% had positive results. Mortality between corticosteroids and control groups was non-significant (RR, 0.93, 95% CI 0.70 to 1.24). At 1 to 3 months follow-up, left ventricular ejection fraction (LVEF) was higher in the corticosteroids group compared to the control group (MD 7.36%, 95% CI 4.94 to 9.79), but there was substantial heterogeneity. Benefits were observed in LVEF in two trials with 200 children given corticosteroids (MD 9.00%, 95% CI 7.48 to 10.52). New York Heart Association (NYHA) class and left ventricular end-stage systole diameter (LVESD) were not affected. Creatine phosphokinase (CPK) (MD -104.00 U/L, 95% CI -115.18 to -92.82), Isoenzyme of creatine phosphate MB (CKMB) (MD 10.35 U/L, 95% CI 8.92 to 11.78), were reduced in the corticosteroids group compared to the control group, although the evidence is limited to small participant numbers. There were insufficient data on adverse events.

AUTHORS' CONCLUSIONS

For people diagnosed with viral myocarditis and low LVEF, corticosteroids do not reduce mortality. They may improve cardiac function but the trials were of low quality and small size so this finding must be regarded as uncertain. High-quality, large-scale RCTs should be careful designed to determine the role of corticosteroid treatment for viral myocarditis. Adverse events should also be carefully evaluated.

Mononuclear cell secretome protects from experimental autoimmune myocarditis

AIMS

Supernatants of serum-free cultured mononuclear cells (MNC) contain a mix of immunomodulating factors (secretome), which have been shown to attenuate detrimental inflammatory responses following myocardial ischaemia. Inflammatory dilated cardiomyopathy (iDCM) is a common cause of heart failure in young patients. Experimental autoimmune myocarditis (EAM) is a CD4+ T cell-dependent model, which mirrors important pathogenic aspects of iDCM. The aim of this study was to determine the influence of MNC secretome on myocardial inflammation in the EAM model.

METHODS AND RESULTS

BALB/c mice were immunized twice with an alpha myosin heavy chain peptide together with Complete Freund adjuvant. Supernatants from mouse mononuclear cells were collected, dialysed, and injected i.p. at Day 0, Day 7, or Day 14, respectively. Myocarditis severity, T cell responses, and autoantibody formation were assessed at Day 21. The impact of MNC secretome on CD4+ T cell function and viability was evaluated using in vitro proliferation and cell viability assays. A single high-dose application of MNC secretome, injected at Day 14 after the first immunization, effectively attenuated myocardial inflammation. Mechanistically, MNC secretome induced caspase-8-dependent apoptosis in autoreactive CD4+ T cells.

CONCLUSION

MNC secretome abrogated myocardial inflammation in a CD4+ T cell-dependent animal model of autoimmune myocarditis. This anti-inflammatory effect of MNC secretome suggests a novel and simple potential treatment concept for inflammatory heart diseases.

Demographics, trends, and outcomes in pediatric acute myocarditis in the United States, 2006 to 2011

BACKGROUND

There is a lack of clear diagnostic and management guidelines for acute myocarditis in the pediatric population. We used a multi-institutional database to characterize demographics, practice variability, and outcomes in this population.

METHODS AND RESULTS

Patients with acute myocarditis (n=514) were identified from April 2006 to March 2011 using the Pediatric Health Information System database, and regional variations in management and outcomes were analyzed. Ninety-seven patients (18.9%) received extracorporeal membrane oxygenation, 22 (4.3%) received ventricular assist device, 21 (4.1%) received heart transplantation, and 37 (7.2%) died. Of the 104 patients who received extracorporeal membrane oxygenation or ventricular assist device, 17 (16.3%) had heart transplantation, 25 (24%) died, and 62 (59.6%) showed recovery of myocardial function. There was a decrease in the use of endomyocardial biopsy (P=0.03) and an increase in the use of magnetic resonance imaging (P<0.01) over the study period. Although the use of medications and procedures varied between different regions, the occurrence of death or heart transplantation showed no significant regional associations. The use of extracorporeal membrane oxygenation (odds ratio, 5.8; 95% confidence interval, 2.9-11.4; P<0.01), ventricular assist device (odds ratio, 8.2; 95% confidence interval, 2.7-24.9; P<0.01), and vasoactive medications (odds ratio, 5.7; 95% confidence interval, 1.2-26.1; P=0.03) was independently associated with death/transplantation.

CONCLUSIONS

There is significant temporal and regional variation in the diagnostic modalities and management used for pediatric myocarditis, which continues to have high morbidity and mortality. Extracorporeal membrane oxygenation, ventricular assist device, and vasoactive medications are independently associated with increased mortality/transplantation.

Early predictors of survival to and after heart transplantation in children with dilated cardiomyopathy

BACKGROUND

The importance of clinical presentation and pretransplantation course on outcome in children with dilated cardiomyopathy listed for heart transplantation is not well defined.

METHODS AND RESULTS

The impact of age, duration of illness, sex, race, ventricular geometry, and diagnosis of myocarditis on outcome in 261 children with dilated cardiomyopathy enrolled in the Pediatric Cardiomyopathy Registry and Pediatric Heart Transplant Study was studied. End points included listing as United Network for Organ Sharing status 1, death while waiting, and death after transplantation. The median age at the time of diagnosis was 3.4 years, and the mean time from diagnosis to listing was 0.62±1.3 years. Risk factors associated with death while waiting were ventilator use and older age at listing in patients not mechanically ventilated (P=0.0006 and P=0.03, respectively). Shorter duration of illness (P=0.04) was associated with listing as United Network for Organ Sharing status 1. Death after transplantation was associated with myocarditis at presentation (P=0.009), nonwhite race (P<0.0001), and a lower left ventricular end-diastolic dimension z score at presentation (P=0.04). In the myocarditis group, 17% (4 of 23) died of acute rejection after transplantation.

CONCLUSIONS

Mechanical ventilator use and older age at listing predicted death while waiting, whereas nonwhite race, smaller left ventricular dimension, and myocarditis were associated with death after transplantation. Although 97% of children with clinically or biopsy-diagnosed myocarditis at presentation survived to transplantation, they had significantly higher posttransplantation mortality compared with children without myocarditis, raising the possibility that preexisting viral infection or inflammation adversely affects graft survival.

Myocarditis

Myocarditis is an underdiagnosed cause of acute heart failure, sudden death, and chronic dilated cardiomyopathy. In developed countries, viral infections commonly cause myocarditis; however, in the developing world, rheumatic carditis, Trypanosoma cruzi, and bacterial infections such as diphtheria still contribute to the global burden of the disease. The short-term prognosis of acute myocarditis is usually good, but varies widely by cause. Those patients who initially recover might develop recurrent dilated cardiomyopathy and heart failure, sometimes years later. Because myocarditis presents with non-specific symptoms including chest pain, dyspnoea, and palpitations, it often mimics more common disorders such as coronary artery disease. In some patients, cardiac MRI and endomyocardial biopsy can help identify myocarditis, predict risk of cardiovascular events, and guide treatment. Finding effective therapies has been challenging because the pathogenesis of chronic dilated cardiomyopathy after viral myocarditis is complex and determined by host and viral genetics as well as environmental factors. Findings from recent clinical trials suggest that some patients with chronic inflammatory cardiomyopathy have a progressive clinical course despite standard medical care and might improve with a short course of immunosuppression.

The evolving approach to paediatric myocarditis: a review of the current literature

Paediatric myocarditis remains challenging from the perspectives of diagnosis and management. Multiple aetiologies exist and the majority of cases appear to be related to viral illnesses. Enteroviruses are believed to be the most common cause, although cases related to adenovirus may be more frequent than suspected. The clinical presentation is extremely varied, ranging from asymptomatic to sudden unexpected death. A high index of suspicion is crucial. There is emerging evidence to support investigations such as serum N-terminal B-type natriuretic peptide levels, as well as cardiac magnetic resonance imaging as adjuncts to the clinical diagnosis. In the future, these may reduce the necessity for invasive methods, such as endomyocardial biopsy, which remain the gold standard. Management generally includes supportive care, consisting of cardiac failure medical management, with the potential for mechanical support and cardiac transplantation. Treatments aimed at immunosuppression remain controversial. The paediatric literature is extremely limited with no conclusive evidence to support or refute these strategies. This article summarises the current literature regarding aetiology, clinical presentation, diagnosis, and management of myocarditis in paediatric patients.

Acute myocarditis in children

Myocarditis is an uncommon but significant disease in children. Diagnosis requires a high index of suspicion and understanding of the clinical presentation of this disease. The understanding of the mechanisms of disease-host immune response and host response has improved, but is not completely known. Therapy remains mainly supportive, while the use of immunotherapy in children is still controversial. The majority of children will improve; however, a substantial portion of children will die or develop persistent dilated cardiomyopathy leading to necessary heart transplantation.

Management and outcomes in pediatric patients presenting with acute fulminant myocarditis

OBJECTIVE

To investigate factors associated with mechanical circulatory support and survival in patients with acute fulminant myocarditis (AFM).

STUDY DESIGN

Retrospective cohort of AFM patients admitted to the cardiac intensive care unit during 1996-2008. AFM was defined as distinct onset of symptoms ≤14 days before admission, rapid-onset cardiogenic shock, and normal left ventricular size. Demographic and physiological variables were compared between patients treated with extracorporeal membrane oxygenation (ECMO) and those who were not and between survivors and nonsurvivors.

RESULTS

Twenty patients (median age 12.7 years) met inclusion criteria. Seventeen patients (85%) survived to hospital discharge. One underwent heart transplantation. Ten (50%) patients required ECMO, and 7 (70%) of these survived. On admission, patients requiring ECMO had elevated lactate (9 vs 1 mmol/L), creatinine (0.8 vs 0.6 mg/dL), and aspartate aminotransferase (256 vs 35 IU/L) (all P < .05) and a trend towards increased incidence of dysrhythmias (80% vs 30%, P = .07). During hospitalization, non-survivors had higher peak lactate (10 vs 3 mmol/L), creatinine (1.5 vs 0.8 mg/dL), and aspartate aminotransferase (3007 vs 156 IU/L) (all P < .05) compared with survivors.

CONCLUSIONS

Patients with AFM with end organ dysfunction or arrhythmias on admission may require mechanical circulatory support. The transplant-free survival rate in this critically ill cohort was excellent (80%).

Myocarditis and pericarditis in children

Myocarditis and pericarditis are rare but important causes of pediatric chest pain. The diagnostic criteria, clinical course, causes, and treatment of myocarditis is reviewed. There is particular attention to the relationship of myocarditis with dilated cardiomyopathy. Supportive therapy remains the standard of care for pump dysfunction. The identification and treatment of pericarditis with associated large pericardial effusion can be lifesaving. This article reviews the important clinical features that might lead the clinician to diagnose either myocarditis or pericarditis and thus separate the few patients with either of these conditions from the legions of children with noncardiac chest pain.

Ventricular Remodeling and Survival Are More Favorable for Myocarditis Than For Idiopathic Dilated Cardiomyopathy in Childhood

Background—

Myocarditis is a cause of a new-onset dilated cardiomyopathy phenotype in children, with small studies reporting high rates of recovery of left ventricular (LV) function.

Methods and Results—

The presenting characteristics and outcomes of children with myocarditis diagnosed clinically and with biopsy confirmation (n=119) or with probable myocarditis diagnosed clinically or by biopsy alone (n=253) were compared with children with idiopathic dilated cardiomyopathy (n=1123). Characteristics at presentation were assessed as possible predictors of outcomes. The distributions of time to death, transplantation, and echocardiographic normalization in the biopsy-confirmed myocarditis and probable myocarditis groups did not differ ( P ≥0.5), but both groups differed significantly from the idiopathic dilated cardiomyopathy group (all P ≤0.003). In children with myocarditis, lower LV fractional shortening z -score at presentation predicted greater mortality (hazard ratio, 0.85; 95% confidence interval, 0.73 to 0.98; P =0.03) and greater LV posterior wall thickness predicted transplantation (hazard ratio, 1.17; 95% confidence interval, 1.02 to 1.35; P =0.03). In those with decreased LV fractional shortening at presentation, independent predictors of echocardiographic normalization were presentation with an LV end-diastolic dimension z -score >2 (hazard ratio, 0.36; 95% confidence interval, 0.22 to 0.58; P <0.001) and greater septal wall thickness (hazard ratio, 1.16; 95% confidence interval, 1.01 to 1.34; P =0.04).

Conclusions—

Children with biopsy-confirmed or probable myocarditis had similar proportions of death, transplantation, and echocardiographic normalization 3 years after presentation and better outcomes than those of children with idiopathic dilated cardiomyopathy. In children with myocarditis who had impaired LV ejection at presentation, rates of echocardiographic normalization were greater in those without LV dilation and in those with greater septal wall thickness at presentation.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT00005391.

Acute viral myocarditis: role of immunosuppression: a prospective randomised study

OBJECTIVE

To conduct a prospective randomised study to show the efficacy of immune suppression with prednisolone, administered at the 3-month duration of acute myocarditis.

METHODS

The diagnosis of acute viral myocarditis was made based on echocardiography and serum viral antibodies. The inclusion criterion was acute myocarditis of 3 months duration. In all, 68 of 173 children were available for randomisation into a prednisolone-treated group of 44 and a control group of 24 children. The follow-up period in the prednisolone-treated group was 15.1 plus or minus 9.2 months and 13.6 plus or minus 10.6 months for the control group.

RESULTS

Compared with controls, 1 month after randomisation significantly more children in the prednisolone-treated group increased their ejection fraction to more than 40% (p = 0.029). Discrete analysis of change in the ejection fraction from the one at randomisation to one after 1 month of randomisation of greater than 10% and less than 10% or no change between groups showed a significantly greater number with improvement in the prednisolone-treated group (p = 0.019). At the end of the follow-up visits, a significantly larger number of children in the prednisolone-treated group had an ejection fraction of more than 60% compared with the control group (p = 0.049).

CONCLUSION

It is concluded that immune suppression with prednisolone, administered at 3 months of the onset of acute myocarditis, is effective in significantly bringing about improvement and cure in persistent left ventricular failure.

Update on myocarditis in children

PURPOSE OF REVIEW

Myocarditis is an uncommon pediatric illness, and it is frequently missed by medical personnel. It often masquerades as more common pediatric illnesses such as respiratory distress or gastrointestinal disease. Given that myocarditis accounts for 12% of sudden cardiac death among adolescents and young adults, the suspicion of this illness in the differential diagnosis of children presenting with nonspecific symptomatology and disease progression can be lifesaving.

RECENT FINDINGS

Historically, the diagnosis of myocarditis required endomyocardial biopsy. More recently ancillary diagnostic modalities have been used to help make the diagnosis less invasively. The use of laboratory testing, echocardiography, and cardiac MRI can now make the diagnosis in the absence of invasive biopsy and can help improve the diagnostic yield when biopsy is performed. Additionally, with an improved understanding of the pathophysiology of this disease, research has focused on novel therapeutic interventions such as immunoglobulin therapy and immunosuppressive therapy in the care of the patient with myocarditis.

SUMMARY

Myocarditis is a challenging diagnosis to make. With advent of newer diagnostic modalities and an improved understanding of the disease and its progression, there is a genuine hope that outcomes of pediatric myocarditis will be improved. The first step, however, is for medical providers to consider this entity in the differential diagnosis of patients with concerning presentation or illness history.

Heart failure in children: clinical aspect and management

Heart failure (HF) is a complex syndrome, with several definitions, the commonest being "an abnormality of cardiac function whereby heart in unable to pump at a rate commensurate with the requirement of the metabolizing tissues, or does so only at elevated filling pressures". In case of children, this requirement includes growth and development. Unlike as seen in adults, HF in children is commonly due to structural heart disease and reversible conditions. Thus the treatment for HF is commonly required for short term only. The overall outcome with HF is better in children than in adults. While the general principles on management are similar to those in adults, the evidence for the use of drugs in children is less convincing. It requires a judicious balance of extrapolation from adult medicine, keeping in mind that children are not small adults.

Greater symptom duration predicts response to immunomodulatory therapy in dilated cardiomyopathy

BACKGROUND

Persistent inflammation contributes to cardiac dysfunction in chronic dilated cardiomyopathy (DCM). Trials of immunomodulatory therapy for DCM have been limited by small sample size and yielded conflicting results. We hypothesized that clinical response to immunomodulation would be dependent on symptom duration. Pooled immunomodulatory trial data was used to test this hypothesis.

METHODS

Data from 130 subjects in 3 randomized, placebo-controlled trials of immunomodulatory therapy in DCM were combined and prospectively analyzed to evaluate change in left ventricular ejection fraction (LV-EF) at 6 and 12 months after randomization by Wilcoxon Rank-Sum test. Logistic regression analysis evaluated correlations between age, gender, symptom duration and change in LV-EF.

RESULTS

Patients >or=6 months of symptoms before immunomodulatory therapy had a greater increase in LV-EF at 6 and 12 months than those receiving placebo (14.4% vs. 4.4%, p<0.001 and 19.5% vs. 5.6%, p<0.001, respectively). Patients with <6 months of symptoms had a similar increase in LV-EF compared to subjects treated with placebo (14.3% vs. 13.3%, p=0.84 and 14.8% vs. 15.2%, p=0.74, respectively). Older age and male gender were not associated with LV-EF change.

CONCLUSION

Immunomodulatory therapy is associated with improved LV-EF in DCM patients with >or=6 or more months of symptom duration.

Molecular biology and pathogenesis of viral myocarditis

Myocarditis is a cardiac disease associated with inflammation and injury of the myocardium. Several viruses have been associated with myocarditis in humans. However, coxsackievirus B3 is still considered the dominant etiological agent. The observed pathology in viral myocarditis is a result of cooperation or teamwork between viral processes and host immune responses at various stages of disease. Both innate and adaptive immune responses are crucial determinants of the severity of myocardial damage, and contribute to the development of chronic myocarditis and dilated cardiomyopathy following acute viral myocarditis. Advances in genomics and proteomics, and in the use of informatics and biostatistics, are allowing unbiased initial evaluations that can be the basis for testable hypotheses about virus pathogenesis and new therapies.

Histology of the explanted hearts of children transplanted for dilated cardiomyopathy

There is little information as to the histology of the explanted hearts of children transplanted for presumed dilated cardiomyopathy. We therefore aimed to describe the histology of these explants. Thirty-six children [mean age 7.4 years (range 0.1-17)] transplanted for dilated cardiomyopathy were identified. Based on histological examination of the explanted hearts patients were classified into three groups: severe inflammation, mild to moderate inflammation, and minimal or no inflammation. Cell death/damage and fibrosis were also scored. Duration of symptoms and degree of support at transplant were ascertained from the case notes. Two patients had severe confluent inflammation, nine mild or moderate focal inflammation, and 25 minimal or no inflammation. The degree of inflammation and fibrosis did not correlate with the interval between presentation and transplant (p = 0.37 and p = 0.78). Patients requiring inotropes or ventricular assist had a shorter time interval between presentation and transplant (p = 0.017) although these levels of support were not associated with the degree of inflammation or fibrosis (p = 0.90 and 0.5). We conclude that the explanted hearts of one-third of children transplanted for presumed cardiomyopathy have some degree of inflammation. Histological findings are not associated with symptom duration or support required.

Sex differences in coxsackievirus B3-induced myocarditis: IL-12Rbeta1 signaling and IFN-gamma increase inflammation in males independent from STAT4

Cardiovascular disease is the number one killer of men and women in North America. Male BALB/c mice infected with coxsackievirus B3 (CVB3) develop more severe inflammatory heart disease compared to female mice, similar to the increased heart disease that occurs in men. We show here that increased inflammation in male mice is not due to increased viral replication in the heart, but associated with increased proinflammatory cytokines IL-1beta, IL-18 and IFN-gamma. We have previously reported that IL-12Rbeta1 signaling increases CVB3-induced myocarditis and IL-1beta/IL-18 levels in males, while IL-12(p35)/STAT4-induced IFN-gamma does not alter the severity of acute disease. However, whether differences exist between males and females in these two cytokine signaling pathways is unknown. In this study, we examined sex differences in 1) IL-12Rbeta1 signaling or 2) STAT4/IFN-gamma pathways following CVB3 infection in BALB/c mice. We found that male and female mice deficient in IL-12Rbeta1 had decreased inflammation and viral replication in the heart, indicating that IL-12Rbeta1 signaling increases myocarditis in both sexes. In contrast, STAT4 deficiency did not alter the sex difference in myocarditis, with males maintaining increased inflammation over females. IFN-gamma deficient males, however, had decreased myocarditis and viral replication compared to females. Thus, IFN-gamma increases inflammation in males independent from STAT4. These results demonstrate that sex differences greatly influence viral replication and the severity of acute CVB3-induced myocarditis.

Evaluating cardiovascular presentations: what does an electrocardiogram have to offer?

The general pediatrician remains the key to the timely recognition and treatment of cardiovascular disorders, particularly those that present acutely and may require immediate attention. In the evaluation of these cardiovascular urgencies, ancillary studies such as the electrocardiogram continue to be important, readily available tools that can aide in the diagnostic process. It is thus incumbent on the general practitioner to foster the skill necessary to employ such tools reliably, particularly in the setting of urgent evaluations. At the same time, recognition of the limitations of such testing will help both in the acute setting and in the understanding of their application in population settings.

Therapy for pediatric myocarditis

Pediatric myocarditis is most often associated with the acute or subacute onset of congestive heart failure in a previously healthy child. Myocarditis presenting with acute, severe symptomatology, termed fulminant myocarditis, has a high rate of recovery. Aggressive supportive care is indicated in fulminant myocarditis, including mechanical circulatory support. For subacute heart failure, supportive care remains the mainstay of therapy for myocarditis. A number of uncontrolled pediatric studies using both immunosuppressive therapy and/or immunomodulating therapy with intravenous gamma globulin have suggested these therapies are safe and useful in treating pediatric myocarditis. However, translating these results into recommended, routine therapy for pediatric myocarditis is complicated by the high rate of spontaneous improvement of myocarditis with supportive care, and the lack of demonstrable benefit for immunosuppressive and immunomodulating therapies in blinded, randomized, placebo-controlled trials in adult myocarditis. Heart transplantation remains the final therapeutic option for children with myocarditis and intractable severe heart failure.