Pediatric Myocarditis: What Have We Learnt So Far?

Epidemiology and prognosis of pediatric acute myocarditis: a 5-year retrospective study in Shiraz, South of Iran running title: pediatric acute myocarditis in Iran

BACKGROUND

Early diagnosis, appropriate management, and vigilant follow-up can lead to the recovery and improved quality of life in many pediatric myocarditis cases. Due to the rarity of this condition, a comprehensive understanding of its epidemiology and outcomes is essential.

AIM

This study aims to provide a thorough epidemiological analysis of pediatric clinically suspected myocarditis and introduce a potential prognostic tool for identifying high-risk patients.

METHOD

A retrospective cross-sectional study was conducted on patients admitted to Namazi Hospital with clinically suspected myocarditis. Demographic, clinical, laboratory, imaging data, and vasoactive inotrope scores were collected from the beginning of hospitalization and throughout the patients' stay. Critical hospital events such as cardioversion, intensive care unit (ICU) care, and mechanical ventilation were documented.

RESULTS

A total of 117 children, including 103 (88%) males, were included in the final evaluation. Patients who required intubation had significantly higher inotrope scores (p-value < 0.0001). Moreover, statistically significant differences were observed in the outcomes of patients presenting with hepatomegaly and decreased left ventricular ejection fraction (P = 0.022).

CONCLUSION

The identification of hepatomegaly and reduced ejection fraction as potential prognostic indicators represents a significant contribution to the field. These findings may assist clinicians in recognizing high-risk patients who require more aggressive treatment and closer monitoring. Patients with elevated inotrope scores are more likely to necessitate mechanical ventilation and cardioversion.

Diagnostic efficacy of soluble ST2 in pediatric fulminant myocarditis

Background and aims

Early identification of fulminant myocarditis (FM) is the key to reducing mortality, but there is still a lack of effective biomarkers for diagnosis. The aim of this study was to investigate the value of soluble ST2 (sST2) in identifying FM in children.

Methods

This was a single-center clinical observational study. We consecutively enrolled 144 children younger than 14 years of age diagnosed with viral myocarditis between January 2018 and November 2023, of whom 63 were diagnosed with FM.

Results

The sST2 level in the FM group was significantly higher than that in the non-FM group [104.40 (68.80, 150.10) vs. 38.30 (19.85, 55.05), p < 0.001]. ROC curves showed that the optimal cut-off values of sST2, TNI, NT-proBNP and CRP for FM were 63.8 ng/ml, 13.3 ng/ml, 3182 pg/ml and 26.5 mg/L, respectively. The sensitivity and specificity of sST2 were 84.13% and 88.9%, indicating the highest early diagnosis efficiency. Multifactorial correction showed that sST2 ≥ 63.8 ng/ml and NT-proBNP ≥ 3182 pg/ml were independent diagnostic predictors of FM (OR = 22.374, 95% CI: 8.140 ∼ 61.499, P < 0.001), and (OR = 3.208, 95% CI: 1.163 ∼ 8.846, P = 0.024).

Conclusions

With high sensitivity and specificity, sST2 may serve as a strong predictor of pediatric FM.

Cardiac Markers in Pediatric Laboratory Medicine: Critical Review

Currently, there are no validated guidelines or recommendations for how to interpret cardiac biomarkers in the pediatric population. The most commonly used cardiac biomarkers are cardiac troponins and natriuretic peptides, but the clinical value of common cardiac biomarkers in pediatric laboratory medicine is restricted due to age- and sex-specific interpretations, and there are no standardized cut-off values. The results from the studies on reference values, as well as results from clinical studies, are difficult to compare with identical studies due to the heterogeneity of subject characteristics (gestational and chronological age, sex, pubertal status, menstrual cycle, exercise), assay characteristics (type of assay, generation of assay, analytical platform used), and experimental protocol characteristics (prospective or retrospective studies, reference population selection, patient population selection, inclusion and exclusion criteria, number of subjects). Future studies need to establish evidence-based cut-offs for specific indications to optimize utilization and standardize the interpretation of common cardiac biomarkers in neonates, children, and adolescents. The aim of this article was to summarize the current analytical and clinical limitations of cardiac troponins and natriuretic peptides in the pediatric population, as informed by the existing published literature.

How to behave with paediatric myocarditis: imaging methods and clinical considerations

Paediatric myocarditis is a challenging and heterogeneous condition, with varied clinical presentations ranging from mild symptoms to life-threatening complications such as heart failure, arrhythmias, and sudden cardiac death. Effective management hinges on early diagnosis, appropriate treatment, and ongoing monitoring, which can be significantly enhanced through multimodal imaging techniques. This review emphasizes the crucial role of advanced imaging in the diagnosis, prognostication, and management of paediatric myocarditis. While traditional echocardiography remains the first-line imaging tool, it is often insufficient in detecting subtle myocardial changes and it does not allow the identification of myocardial inflammation and fibrosis, particularly in cases with preserved left ventricular function. Recent advancements, including speckle-tracking echocardiography, provide enhanced sensitivity for detecting early signs of myocardial dysfunction, even in the absence of overt abnormalities. Cardiovascular magnetic resonance (CMR) has emerged as a cornerstone in the non-invasive evaluation of myocarditis, offering unparalleled tissue characterization. Indeed, CMR provides critical insights into myocardial oedema, necrosis, and fibrosis, which are essential for confirming the diagnosis, stratifying prognosis, and guiding therapy. Parametric mapping techniques allow for highly accurate detection of myocardial fibrosis (native T1 mapping) and inflammation (T2 mapping), even in the absence of gadolinium contrast, making it particularly valuable in paediatric patients. In conclusion, multimodality imaging, integrating echocardiography and CMR, allows for a comprehensive understanding of disease severity, guiding treatment decisions and optimizing long-term outcomes. This review underscores the importance of a tailored, imaging-driven approach to managing paediatric myocarditis, ensuring the best possible care for this special population.

Neonatal Enterovirus-Associated Myocarditis in Dizygotic Twins: Myocardial Longitudinal Strain Pattern Analysis

Enteroviruses (EVs) are the most common causes of viral myocarditis in neonates. Neonatal enterovirus myocarditis manifestations range from nonspecific febrile illness to congestive heart failure and cardiogenic shock with high risk of in-hospital mortality and long-term cardiac sequelae. Early recognition is essential to undertake appropriate therapy and predict outcomes. Echocardiography and echo-derived left ventricular strain measures seem promising for these purposes. We herein report two cases of neonatal enterovirus-associated myocarditis in dichorionic diamniotic twins, with different presentation, clinical course, and intensity of treatments.

Role of CCRL2 in the Pathogenesis of Experimental Autoimmune Myocarditis via P21-Activated Kinase 1/NOD-Like Receptor Protein 3 Pathway

Myocarditis, a severe inflammatory disease, is becoming a worldwide public health concern. This study aims to elucidate the effect of Chemokine (C C motif) receptor-like 2 (CCRL2) in experimental autoimmune myocarditis (EAM) occurrence and its potential regulatory mechanisms.EAM was simulated in a mouse model injected with α-myosin-heavy chain. The changes on EAM were assessed through histological staining of heart tissues, including measuring cardiac troponin I (cTnI), proinflammatory cytokines, transferase-mediated dUTP nick end labeling (TUNEL) assay, and cardiac function. Then, the heart tissues from the EAM mouse model and control groups were analyzed through transcriptome sequencing to identify the differential expressed genes (DEGs) and hub genes related to pyroptosis. Downregulation of CCRL2 further verified the function of CCRL2 on EAM and p21-activated kinase 1/NOD-like receptor protein 3 (PAK/NLRP3) signaling pathways in vivo.The EAM model was constructed successfully, with the heart weight/body weight ratio, serum level of cTnI, and concentrations of proinflammatory cytokines elevation. Moreover, cell apoptosis was also significantly increased. Transcriptome sequencing revealed 696 and 120 upregulated and downregulated DEGs, respectively. After functional enrichment, CCRL2 was selected as a potential target. Then, we verified that CCRL2 knockdown improved cardiac function, alleviated EAM occurrence, and reduced PAK/NLRP3 protein expression.CCRL2 may act as a novel potential treatment target in EAM by regulating the PAK1/NLRP3 pathway.

Role of Biomarkers in the Management of Immune-Checkpoint Inhibitor-Related Myocarditis

PURPOSE OF REVIEW

Immune checkpoint inhibitor (ICI)-related myocarditis poses a major clinical challenge given its non-specific presentation, rapid progression, and high mortality rate. Here, we review the role of blood-based biomarkers in the clinical management of patients with ICI-related myocarditis.

RECENT FINDINGS

Myocardial injury, its unique pattern, and the co-occurrence with myositis are defining features of ICI-related myocarditis. Non-cardiac biomarkers, specifically creatinine phosphokinase, precedes the symptomatic presentation and is highly sensitive for diagnosing ICI-related myocarditis, making them useful screening biomarkers. Combined elevations in cardiac troponins and non-cardiac biomarkers improve the confidence of an ICI myocarditis diagnosis. High troponin and creatinine phosphokinase levels are strongly associated with severe outcomes. We propose biomarker-based algorithms for the monitoring and diagnosis of ICI-related myocarditis. Biomarkers, such as cardiac troponins and creatine phosphokinase, can be used in combination in the monitoring, diagnosis, and prognostication of patients with ICI-related myocarditis.

Non-invasive pediatric cardiac imaging-current status and further perspectives

BACKGROUND

Non-invasive cardiac imaging has a growing role in diagnosis, differential diagnosis, therapy planning, and follow-up in children and adolescents with congenital and acquired cardiac diseases. This review is based on a systematic analysis of international peer-reviewed articles and additionally presents own clinical experiences. It provides an overview of technical advances, emerging clinical applications, and the aspect of artificial intelligence.

MAIN BODY

The main imaging modalities are echocardiography, CT, and MRI. For echocardiography, strain imaging allows a novel non-invasive assessment of tissue integrity, 3D imaging rapid holistic overviews of anatomy. Fast cardiac CT imaging new techniques-especially for coronary assessment as the main clinical indication-have significantly improved spatial and temporal resolution in adjunct with a major reduction in ionizing dose. For cardiac MRI, assessment of tissue integrity even without contrast agent application by mapping sequences is a major technical breakthrough. Fetal cardiac MRI is an emerging technology, which allows structural and functional assessment of fetal hearts including even 4D flow analyses. Last but not least, artificial intelligence will play an important role for improvements of data acquisition and interpretation in the near future.

CONCLUSION

Non-invasive cardiac imaging plays an integral part in the workup of children with heart disease. In recent years, its main application congenital heart disease has been widened for acquired cardiac diseases.

How to interpret cardiac biomarkers in children?

Cardiac biomarkers are used as first-line diagnostic tools in suspected myocardial injury and heart failure in adult patients. Their use in paediatric patients has been limited by variability caused by age, gender and the presence of an underlying congenital cardiac condition. There are established reference ranges for both NT-proBNP and troponin in healthy children, but these cannot be applied to all paediatric patients because of limited large studies focusing on children with congenital heart disease and/or cardiomyopathy.This article will focus on the pathophysiology of myocardial injury and heart failure in children and the subsequent cardiac biomarker correlation. It will explain how to interpret the biomarker assay levels obtained for both troponin and NT-proBNP and highlights the importance of a clear clinical question prior to requesting a cardiac biomarker assay level.Clinical cases outline scenarios that may prompt consideration of biomarker analysis in children and aims to equip the reader with an understanding of how to interpret the results.

Heart Disease and Arboviruses: A Systematic Review and Meta-Analysis

Dengue fever, chikungunya, and zika are highly prevalent arboviruses transmitted by hematophagous arthropods, with a widely neglected impact in developing countries. These diseases cause acute illness in diverse populations, as well as potential cardiovascular complications. A systematic review was carried out to investigate the burden of cardiac involvement related to these arboviruses. Multiple databases were searched for articles that investigated the association of cardiovascular diseases with arboviruses, published up to March 2022. Relevant articles were selected and rated by two independent reviewers. Proportion meta-analysis was applied to assess the frequency-weighted mean of the cardiovascular findings. A total of 42 articles were selected (n = 76,678 individuals), with 17 manuscripts on dengue and 6 manuscripts on chikungunya undergoing meta-analysis. The global pooled incidence of cardiac events in dengue fever using a meta-analysis was 27.21% (95% CI 20.21–34.83; I² = 94%). The higher incidence of dengue-related myocarditis was found in the population younger than 20 years old (33.85%; 95% CI 0.00–89.20; I² = 99%). Considering the studies on chikungunya (n = 372), the global pooled incidence of cardiac involvement using a meta-analysis was 32.81% (95% CI 09.58–61.49, I² = 96%). Two Zika studies were included that examined cases of infection by vertical transmission in Brazil, finding everything from structural changes to changes in heart rate variability that increase the risk of sudden death. In conclusion, cardiac involvement in arboviruses is not uncommon, especially in dengue fever.