Diagnosis and Treatment of Myocarditis in Children in the Current Era

Myocarditis in children 2024, new themes and continued questions

PURPOSE OF REVIEW

While pediatric myocarditis incidence has increased since the coronavirus disease 2019 (COVID-19) pandemic, there remain questions regarding diagnosis, risk stratification, and optimal therapy. This review highlights recent publications and continued unanswered questions related to myocarditis in children.

RECENT FINDINGS

Emergence from the COVID-19 era has allowed more accurate description of the incidence and prognosis of myocarditis adjacent to COVID-19 infection and vaccine administration as well that of multi-system inflammatory disease in children (MIS-C). As cardiac magnetic resonance technology has shown increased availability and evidence in pediatric myocarditis, it is important to understand conclusions from adult imaging studies and define the use of this imaging biomarker in children. Precision medicine has begun to allow real-time molecular evaluations to help diagnose and risk-stratify cardiovascular diseases, with emerging evidence of these modalities in myocarditis.

SUMMARY

Recent information regarding COVID-19 associated myocarditis, cardiac magnetic resonance, and molecular biomarkers may help clinicians caring for children with myocarditis and identify needs for future investigations.

Cardiac evaluation of patients with juvenile dermatomyositis

BACKGROUND

The present study aims to evaluate possible cardiac involvement in juvenile dermatomyositis (JDM) patients by conventional methods and cardiac magnetic resonance imaging (MRI) along with a systematic review of the literature on cardiac features in JDM.

METHODS

The study group consisted of JDM patients who underwent cardiac MRI. We conducted a systematic review of the published literature involving JDM patients with cardiac involvement.

RESULTS

In the present study, although baseline cardiologic evaluations including electrocardiography and echocardiography were within normal limits, we showed late gadolinium enhancement on cardiac MRI in 3 of 11 JDM patients. In the literature review, we identified 25 articles related to cardiac involvement in JDM. However, none of them, except one case report, included cardiac MRI of JDM patients.

CONCLUSION

Cardiac abnormalities have been reported among the less frequent findings in patients with JDM. Cardiovascular complications during the long-term disease course are a leading cause of morbidity and mortality in these patients. Early detection of cardiac involvement by cardiac MRI in patients with JDM and aggressive treatment of them may improve the clinical course of these patients.

IMPACT

The myocardium in patients with JDM may be involved by inflammation. Myocardial involvement may be evaluated by using contrast-enhanced cardiac MRI. This is the first study evaluating cardiac involvement by cardiac MRI in JDM patients. MRI may show early cardiac involvement in patients whose baseline cardiologic evaluations are within normal limits. Early detection of cardiac involvement by cardiac MRI may improve the long-term prognosis of patients with JDM.

Pediatric dilated cardiomyopathy: a review of current clinical approaches and pathogenesis

Pediatric dilated cardiomyopathy (DCM) is a rare, yet life-threatening cardiovascular condition characterized by systolic dysfunction with biventricular dilatation and reduced myocardial contractility. Therapeutic options are limited with nearly 40% of children undergoing heart transplant or death within 2 years of diagnosis. Pediatric patients are currently diagnosed based on correlating the clinical picture with echocardiographic findings. Patient age, etiology of disease, and parameters of cardiac function significantly impact prognosis. Treatments for pediatric DCM aim to ameliorate symptoms, reduce progression of disease, and prevent life-threatening arrhythmias. Many therapeutic agents with known efficacy in adults lack the same evidence in children. Unlike adult DCM, the pathogenesis of pediatric DCM is not well understood as approximately two thirds of cases are classified as idiopathic disease. Children experience unique gene expression changes and molecular pathway activation in response to DCM. Studies have pointed to a significant genetic component in pediatric DCM, with variants in genes related to sarcomere and cytoskeleton structure implicated. In this regard, pediatric DCM can be considered pediatric manifestations of inherited cardiomyopathy syndromes. Yet exciting recent studies in infantile DCM suggest that this subset has a distinct etiology involving defective postnatal cardiac maturation, such as the failure of programmed centrosome breakdown in cardiomyocytes. Improved knowledge of pathogenesis is central to developing child-specific treatment approaches. This review aims to discuss the established biological pathogenesis of pediatric DCM, current clinical guidelines, and promising therapeutic avenues, highlighting differences from adult disease. The overarching goal is to unravel the complexities surrounding this condition to facilitate the advancement of novel therapeutic interventions and improve prognosis and overall quality of life for pediatric patients affected by DCM.

COVID-19 and cardiac complications: Myocarditis and multisystem inflammatory syndrome in children

Coronavirus is an important pathogen causing disease in humans and animals. At the end of 2019, an investigation into an increase in pneumonia cases in Wuhan, Hubei Province, China, found that the cause was a new coronavirus. This disease, which spread rapidly across China and caused an outbreak worldwide, resulted in a pandemic. Although this virus has previously been referred to as 2019-nCoV, which causes coronavirus disease 2019 (COVID-19), later it was named severe acute respiratory syndrome coronavirus 2. Children were usually asymptomatic and rarely severely affected. In April 2020, reports from the United Kingdom indicated that children may have Kawasaki disease or a clinical condition similar to toxic shock syndrome. This clinical picture was later defined as multisystem inflammatory syndrome in children. Since then, similarly affected children as well as cases with other cardiac complications have been reported in other parts of the world. In this review, we aimed to evaluate COVID-19 in terms of cardiac involvement by reviewing the literature.

The diagnosis and treatment of pediatric clinical myocarditis in China: a multicenter retrospective study

This study aims to examine the clinical characteristics and outcomes of clinical myocarditis in pediatric patients in China. This is a multicenter retrospective study. Children diagnosed with clinical myocarditis from 20 hospitals in China and admitted between January 1, 2015, and December 30, 2021, were enrolled. The clinical myocarditis was diagnosed based on the "Diagnostic Recommendation for Myocarditis in Children (Version 2018)". The clinical data were collected from their medical records. A total of 1210 patients were finally enrolled in this study. Among them, 45.6% had a history of respiratory tract infection. An abnormal electrocardiogram was observed in 74.2% of patients. Echocardiography revealed that 32.3% of patients had a left ventricular ejection fraction of less than 50%. Cardiac MRI was performed in 4.9% of children with clinical myocarditis, of which 61% showed localized or diffuse hypersignal on T2-weighted images. Serum levels of cardiac troponin I (cTnI), creatine kinase-MB (CK-MB), and N-terminal B-type natriuretic peptide (NT-proBNP) were higher in patients with fulminant myocarditis than in patients with myocarditis, making them potential risk factors for fulminant myocarditis. Following active treatment, 12.1% of patients were cured, and 79.1% were discharged with improvement.

CONCLUSION

Clinical myocarditis in children often presents with symptoms outside the cardiovascular system. CK-MB, cTnI, and NT-proBNP are important indicators for assessing clinical myocarditis. The electrocardiogram and echocardiogram findings in children with clinical myocarditis exhibit significant variability but lack specificity. Cardiac MRI can be a useful tool for screening clinical myocarditis. Most children with clinical myocarditis have a favorable prognosis.

WHAT IS KNOWN

• Pediatric myocarditis presents complex clinical manifestations and exhibits varying degrees of severity. Children with mild myocarditis generally have a favorable prognosis, while a small number of children with critically ill myocarditis experience sudden onset, hemodynamic disorders, and fatal arrhythmias. Therefore, early diagnosis and timely treatment of myocarditis are imperative.

WHAT IS NEW

• To the best of our knowledge, this multicenter retrospective study is the largest ever reported in China, aiming to reveal the clinical characteristics and outcomes of pediatric clinical myocarditis in China. We provided an extensive analysis of the clinical characteristics, diagnosis, treatment, prognosis, and factors impacting disease severity in pediatric clinical myocarditis in China, which provides insights into the epidemiological characteristics of pediatric clinical myocarditis.

Transient second-degree high-grade atrioventricular block caused by myocarditis

Myocarditis is an inflammatory disease of the heart muscle that most commonly occurs after infectious diseases in childhood. The clinical picture of acute myocarditis ranges from asymptomatic infection to fulminant heart failure and sudden death (1). Most of the patients may present with nonspecific symptoms such as respiratory distress, chest pain, nausea, and vomiting (2). While rhythm abnormalities such as ventricular and supraventricular rhythm disorders can be observed in these patients, various degrees of atrioventricular blocks may rarely develop (3). In this article, we aimed to present a patient who developed second-degree, high-grade atrioventricular block after myocarditis and recovered completely after treatment.

Survival in a young child with out-of-hospital cardiac arrest: diagnostic dilemma and when to deviate from standard resuscitation guidelines

A boy in early childhood presented in cardiac arrest. Care was provided out of hospital and in the emergency department as per standard paediatric resuscitation guidelines. Despite initial return of spontaneous circulation following cardiopulmonary resuscitation, two defibrillation shocks and epinephrine via intraosseous access, he had recurrent episodes of pulseless ventricular tachycardia and ventricular fibrillation. In total, 40 defibrillation shocks were administered, and he subsequently stabilised on combined treatment with intravenous esmolol, amiodarone and milrinone. He was transferred to the paediatric intensive care unit and had an automated implantable cardioverter-defibrillator inserted prior to discharge. Genetic testing has confirmed a diagnosis of catecholaminergic polymorphic ventricular tachycardia and it is hypothesised that the childhood excitement at a popular time of year, combined with caffeinated drinks, instigated his initial cardiac arrest which was propagated with iatrogenic epinephrine. He has remained stable since, with no neurological sequelae thus far from a significantly prolonged downtime.

A teenager with adenoviral myocarditis mimicking hypertrophic cardiomyopathy

A 14-year-old previously healthy female presented with chest pain and dyspnoea for 2 days in the setting of a recent upper respiratory infection. She had elevated inflammatory markers and troponin, resulting in the diagnosis of acute myocarditis. Transthoracic echocardiography demonstrated mild systolic dysfunction and a moderate pericardial effusion. Additionally, her echocardiogram showed concentric left ventricular hypertrophy raising concern for hypertrophic cardiomyopathy. She was treated with intravenous immunoglobulin. Serial echocardiograms revealed rapid resolution of her ventricular hypertrophy. Cardiac magnetic resonance confirmed the diagnosis of myocarditis.

Immunopathogenesis and immunomodulatory therapy for myocarditis

Myocarditis is an inflammatory cardiac disease characterized by the destruction of myocardial cells, infiltration of interstitial inflammatory cells, and fibrosis, and is becoming a major public health concern. The aetiology of myocarditis continues to broaden as new pathogens and drugs emerge. The relationship between immune checkpoint inhibitors, severe acute respiratory syndrome coronavirus 2, vaccines against coronavirus disease-2019, and myocarditis has attracted increased attention. Immunopathological processes play an important role in the different phases of myocarditis, affecting disease occurrence, development, and prognosis. Excessive immune activation can induce severe myocardial injury and lead to fulminant myocarditis, whereas chronic inflammation can lead to cardiac remodelling and inflammatory dilated cardiomyopathy. The use of immunosuppressive treatments, particularly cytotoxic agents, for myocarditis, remains controversial. While reasonable and effective immunomodulatory therapy is the general trend. This review focuses on the current understanding of the aetiology and immunopathogenesis of myocarditis and offers new perspectives on immunomodulatory therapies.

Ultra-early myocardial calcification secondary to fulminant myocarditis with 4 years of follow-up: a case report

BACKGROUND

Early myocardial calcifications secondary to fulminant myocarditis (FM) are rare, and their natural evolution and effects on cardiac function are poorly understood. Here, we followed the patient for 4 years to observe the development of cardiac calcification and its impact on heart function.

CASE SUMMARY

A 16-year-old man was hospitalized with a fever and cough for 1 day. The patient was previously healthy and had no history of heart disease or specific family conditions. The patient was positive for anti-Epstein-Barr virus IgG and IgM. The computed tomography (CT) scan showed no coronary lesions. Cardiogenic shock and recurrent ventricular fibrillation developed on the third day after admission, and the patient received rescue therapy such as endotracheal intubation, defibrillation, extracorporeal membrane oxygenation, and corticosteroids. On the 13th day of admission, a CT scan revealed significant calcification in the left ventricular wall. The patient was discharged after 30 days in the hospital. After discharge, his left ventricular calcification peaked at 6 months and gradually subsided after that, and his left ventricular function slowly returned to normal at 12 months.

DISCUSSION

In younger patients, myocardial calcifications secondary to FM may occur as early as 13 days and affect cardiac function. After proper treatment and rehabilitation, the patient's myocardial calcification can gradually subside and the cardiac function can gradually recover. For FM patients, timely and comprehensive intensive treatment, including heart, lung, and kidney replacement therapy and early administration of hormone preparations, may be beneficial to the early recovery of patients.

Features of Myocarditis: Morphological Differential Diagnosis in Post-COVID-19 Children

Myocarditis is characterized by dysfunction and destruction of cardiomyocytes, infiltrative inflammation, and development of fibrosis. Late diagnosis of myocarditis has been a serious global health problem, especially due to the spread of a new coronavirus infection. The aim of this review is to identify differences between myocarditis of viral etiology, including SARS-CoV-2 lesions, based on instrumental and pathomorphological findings.

MATERIAL AND METHODS

We analyzed publications covering the period from December 2019 to May 2023, published in publicly accessible international databases ("Medline", "PubMed", "Scopus"), with queries for the keywords "myocarditis", "children", "cardiovascular inflammation", "COVID-19", "SARS-CoV-2", "severe acute respiratory syndrome coronavirus 2", "differential diagnosis".

RESULTS

It was found that no unambiguous morphological criteria for the diagnosis of myocarditis coupled to SARS-CoV-2 lesions were identified. However, the detected histopathological changes such as virus-associated degeneration, apoptosis, cardiomyocyte necrosis, moderate interstitial hyperemia, myocardial tissue oedema, and capillary endothelial cell dysfunction were the major markers of SARS-CoV-2 infection.

CONCLUSION

It is necessary further reconsider morphological criteria to diagnose SARS-CoV-2-caused myocarditis, rather than solely relying on detecting viral RNA by PCR as the sole evidence-based criterion. Similar issues accompany diagnostics of myocardial lesions associated with other viral infections. Evidence for an etiological diagnosis of myocarditis can be provided by a comprehensive analysis of the diagnostic criteria obtained, confirming virus exposure, followed by development of distinct clinical symptoms, MRI and CT changes, and morphological criteria.

Myocardial Injury Thresholds for 4 High-Sensitivity Troponin Assays in a Population-Based Sample of US Children and Adolescents

BACKGROUND

Myocardial injury is an important pediatric diagnosis. Establishing normative data from a representative pediatric sample is vital to provide accurate upper reference limits (URLs) for defining myocardial injury using high-sensitivity cardiac troponin.

METHODS

Among participants 1 to 18 years of age in the 1999-2004 National Health and Nutrition Examination Survey, we measured high-sensitivity troponin T using one assay (Roche) and high-sensitivity troponin I using 3 assays (Abbott, Siemens, and Ortho). In a strictly defined healthy subgroup, we estimated 97.5th and 99th percentile URLs for each assay using the recommended nonparametric method.

RESULTS

Of 5695 pediatric participants, 4029 met criteria for the healthy subgroup (50% males; mean age 12.6 years). Our 99th percentile URL estimates for all 4 high-sensitivity troponin assays among children and adolescents were lower than the manufacturer-reported URLs (derived from adults). The 99th percentile URLs (95% CI) were 15 ng/L (95% CI, 12-17) for high-sensitivity troponin T, 16 ng/L (95% CI, 12-19) for high-sensitivity troponin I with the Abbott assay, 38 ng/L (95% CI, 25-46) for high-sensitivity troponin I with the Siemens assay, and 7 ng/L (95% CI, 5, 12) for high-sensitivity troponin I with the Ortho assay. The 95% CIs for age-, sex-, and race and ethnicity-specific 99th percentile URLs overlapped. However, the 97.5th percentile URL for each assay was measured with superior statistical precision (ie, tighter 95% CIs) and demonstrated differences by sex. For male compared with female children and adolescents, 97.5th percentile URLs were 11 ng/L (95% CI, 10-12) versus 6 ng/L (95% CI, 6-7) for high-sensitivity troponin T, 9 ng/L (95% CI, 7-10) versus 5 ng/L (95% CI, 4-6) for high-sensitivity troponin I with the Abbott assay, 21 ng/L (95% CI, 18-25) versus 11 ng/L (95% CI, 9-13) for high-sensitivity troponin I with the Siemens assay, and 4 ng/L (95% CI, 3-5) versus 2 ng/L (95% CI, 1-3) for high-sensitivity troponin I with the Ortho assay. In contrast to the 99th percentiles, the point estimates of 97.5th percentile pediatric URLs for high-sensitivity troponin were also much more stable to differences in the analytic approaches taken to estimate URLs.

CONCLUSIONS

Because myocardial infarction is rare in children and adolescents, the use of statistically more precise and reliable sex-specific 97.5th percentile high-sensitivity troponin URLs might be considered to define pediatric myocardial injury.

Myocarditis: Etiology, Pathogenesis, and Their Implications in Clinical Practice

Myocarditis is an inflammatory disease of the myocardium caused by infectious or non-infectious agents. It can lead to serious short-term and long-term sequalae, such as sudden cardiac death or dilated cardiomyopathy. Due to its heterogenous clinical presentation and disease course, challenging diagnosis and limited evidence for prognostic stratification, myocarditis poses a great challenge to clinicians. As it stands, the pathogenesis and etiology of myocarditis is only partially understood. Moreover, the impact of certain clinical features on risk assessment, patient outcomes and treatment options is not entirely clear. Such data, however, are essential in order to personalize patient care and implement novel therapeutic strategies. In this review, we discuss the possible etiologies of myocarditis, outline the key processes governing its pathogenesis and summarize best available evidence regarding patient outcomes and state-of-the-art therapeutic approaches.

Leitlinie Myokarditis der Deutschen Gesellschaft für Pädiatrische Kardiologie

This consensus statement presents updated recommendations on diagnosis and treatment of myocarditis in childhood.

Admission and follow-up cardiac magnetic resonance imaging findings in BNT162b2 Vaccine-Related myocarditis in adolescents

BACKGROUND

There is limited data on the pattern and severity of myocardial injury in patients with COVID-19 vaccination associated myocarditis.

OBJECTIVE

We aimed to define the myocardial damage occurring after BNT162b2 vaccination, raise awareness about adverse reactions developing after vaccination, and determine the patterns and scope of Cardiac magnetic resonance imaging (MRI) findings.

PATIENTS/METHODS

A total of 9 patients diagnosed with vaccine-associated myopericarditis were followed up.

RESULTS

The mean age of the patient at diagnosis was 15.3 ± 1.0 (range: 14-17) years, and all patients were male. Seven patients presented with myocarditis symptoms after their second vaccine dose, one patient presented with pericarditis symptoms after his first dose, and the other patient presented with myocarditis symptoms after his booster dose. The median time at presenting to the hospital was 3 (range: 2-22) days. Seven (77.7%) patients had abnormal electrocardiography (ECG) findings, and the most prevalent finding was diffuse ST-segment elevation. Initial cardiac MRI results were abnormal in all patients, where 8 (88.8%) patients had late gadolinium enhancement, and 5 (55.5%) had myocardial edoema. Three patients showed local left ventricular wall-motion abnormalities. In their follow-up MRIs 3-6 months later, myocardial edoema was present in 2 (28.5%) patients, while late gadolinium enhancement was present in all patients (7/7, 100%, 2 patients did not have control MRI time). Hypokinetic segments were still present in one of the 3 patients. No negative cardiac events were observed in the short-term follow-up of any patient.

CONCLUSION

Further follow-up evaluation and larger multicenter studies are needed to determine the clinical significance of persistent cardiac MRI abnormalities.

A Novel Marker for Predicting Fulminant Myocarditis: Systemic Immune-Inflammation Index

In myocarditis, the search for effective and appropriate prognostic biomarkers can help clinicians identify high-risk patients in a timely manner and make better medical decisions in clinical practice. The prognostic value of systemic immune-inflammatory index (SII), an innovate biomarker of inflammation, in fulminant myocarditis in children has not been assessed. This study aims to (1) determine the effect of SII and other inflammatory markers on the prognosis of patients with myocarditis, and (2) characterize other factors affecting adverse outcomes in myocarditis. All patients aged between 1 months and 18 years who admitted to Pediatric Emergency Department between January 1, 2015 and October 1, 2021 and were diagnosed with myocarditis were retrospectively analyzed. 106 Eligible subjects were enrolled (67% male, 12.5 years (IQR 6-16). Fulminant myocarditis developed in 16 (15%) of the patients. The median SII was 1927 (1147.75-3610.25) in the fulminant myocarditis group and 351 (251.75-531.25) in the non-fulminant group (p < 0.001). In estimation of fulminant myocarditis, AUC was 0.87 for WBC [95% confidence interval (CI) 0.72-1.00, p = 0.002], 0.94 for ANC (95% CI 0.85-1.00), p = 0.000), 0.92 for SII (95% CI 0.82-1.00, p = 0.000). Spearman's correlation analysis showed a significant negative correlation between SII and LVEF (r = 0.576, p < 0.001). The highest AUC values were associated with ANC, SII, and WBC levels to predict fulminant myocarditis. SII, a readily available biomarker from routine blood parameters, allows early recognition of negative outcomes and can independently predict the prognosis of myocarditis in children.

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.

Waitlist and post-transplant outcomes for children with myocarditis listed for heart transplantation over 3 decades

BACKGROUND

There is limited and conflicting information on waitlist and transplant outcomes for children with myocarditis.

METHODS

Retrospective review included children with myocarditis and dilated cardiomyopathy (DCM) listed for HT from January 01, 1993 to December 31, 2019 in the Pediatric Heart Transplant Society database. Clinical characteristics, waitlist and post-HT outcomes (graft loss, rejection, cardiac allograft vasculopathy, infection and malignancy) for children listed from early (1993-2008) and current era (2009-2019) with myocarditis were evaluated and compared to those with DCM.

RESULTS

Of 9755 children listed, 322 (3.3%) had myocarditis and 3178 (32.6%) DCM. Compared to DCM, children with myocarditis in the early and the current era were significantly more likely to be listed at higher urgency; be in intensive care unit; on mechanical ventilation; extracorporeal membrane oxygenation and ventricular assist device (p < 0.05 for all). While unadjusted analysis revealed lower transplant rates and higher waitlist mortality for children with myocarditis, in multivariable analysis, myocarditis was not a risk factor for waitlist mortality. Myocarditis, however, was a significant risk factor for early phase post-HT graft loss (HR 2.46; p = 0.003). Waitlist and post-HT survival for children with myocarditis were similar for those listed and transplanted in the early era to those listed and transplanted in the current era (p > 0.05 for both).

CONCLUSIONS

Children with myocarditis have a higher acuity of illness at listing and at HT and have inferior post-HT survival compared to children with DCM. Outcomes for children with myocarditis have not improved over the 3 decades and efforts are needed to improve outcomes for this cohort.

Long-Term Cardiovascular Outcome in Children with MIS-C Linked to SARS-CoV-2 Infection-An Italian Multicenter Experience

Simple Summary

MIS-C is a multisystem inflammatory syndrome that is characterized by severe systemic signs of inflammation and multi-organ failure, including the involvement of the heart. Our study described the long-term cardiovascular outcome in a cohort of pediatric patients with MIS-C, who were admitted to two Italian Pediatric Referral Centers. The number of pediatric patients with an MIS-C diagnosis was 67. Among them, 65% of them had ventricular dysfunction, 66% of them had pericarditis, 35% of them had coronary involvement, and 9% of them showed arrhythmias. Our data described many cases of myocarditis and pericarditis, with mild coronary involvement and a few cases of arrhythmias. This experience showed that cardiac involvement in MIS-C patients is almost the rule, and that LV dysfunction and pericarditis are the most frequent manifestations of it. However, the patients’ clinical course was satisfactory, and during the controls, no additional events or sequelae were observed apart from long-term myocardial scars in 50% of the patients that underwent CMR. Early treatment not only provides a prompt full recovery, but it also has a probably “protective” effect towards late adverse events and long-term complications.

Abstract

MIS-C is a multisystem inflammatory syndrome that is characterized by multi-organ failure and cardiac involvement. The aim of this study was to describe the long-term cardiovascular outcome in a cohort of MIS-C pediatric patients, who were admitted to two Italian Pediatric Referral Centers. Sixty-seven patients (mean age 8.7 ± 4.7 years, male 60%) were included; 65 (97%) of them showed cardiac involvement. All of the patients completed one month of the follow-up, and 47% completed 1 year of it. ECG abnormalities were present in 65% of them, arrhythmias were present in 9% of them during an acute phase and it disappeared at the point of discharge or later. Pericarditis were detected in 66% of them and disappeared after 6 months. Coronaritis was observed in 35% of the children during an acute phase, and there were no more instances at the 1-year point. An LV dysfunction was present in 65% of the patients at the beginning of the study, with them having a full recovery at the point of discharge and thereafter. Elevated values of the NTproBNP and hsTp were initially detected, which progressively decreased and normalized at the points of discharge and FU. The CMR at the point of FU, there was a presence of long-term myocardial scars in 50% of the patients that were tested. No deaths that were caused by MIS-C during the FU were recorded. Cardiac involvement in MIS-C patients is almost the rule, but the patients’ clinical course was satisfactory, and no additional events or sequelae were observed apart from there being long-term myocardial scars in 50% of the patients that underwent CMR.

Cardiac outcomes in severe acute respiratory syndrome coronavirus-2-associated multisystem inflammatory syndrome at a tertiary paediatric hospital

INTRODUCTION

We describe a cohort of children referred with multisystem inflammatory syndrome in children associated with severe acute respiratory syndrome coronavirus 2 and compare this cohort with a 2019 cohort of children with Kawasaki disease.

METHODS

We conducted a retrospective cohort study of 2019 and 2020 referrals to the inflammatory cardiology service at Great Ormond Street Hospital for Children. We compared cardiac and inflammatory parameters of a sub-section of the 2020 cohort who presented with reduced left ventricular ejection fraction with the remainder of the cohort.

RESULTS

Referrals significantly increased between February and June 2020 compared to 2019 (19.8/30 days versus 3.9/30 days). Frequency of coronary artery aneurysms (11/79 (13.9%) versus 7/47 (14.9%)) or severe coronary artery aneurysms (6/79 (7.6%) versus 3/47 (6.4%)) was similar between 2020 and 2019, respectively. The 2020 cohort was older (median age 9.07 years versus 2.38 years), more likely to be of Black, Asian, or other minority ethnic group (60/76 (78.9%) versus 25/42 (59.5%)), and more likely to require inotropic support (22 (27.5%) versus 0 (0%)). Even children with significantly reduced left ventricular ejection fraction demonstrated complete recovery of cardiac function within 10 days (mean 5.25 days ± 2.7).

DISCUSSION

We observed complete recovery of myocardial dysfunction and an overall low rate of permanent coronary sequelae, indicating that the majority of children with multisystem inflammatory syndrome in children are unlikely to encounter long-term cardiac morbidity. Although the frequency of myocardial dysfunction and inotropic support requirement is not consistent with a diagnosis of Kawasaki disease, the frequency of coronary artery abnormalities and severe coronary artery abnormalities suggests a degree of phenotypic overlap.

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.

Anakinra in pediatric acute fulminant myocarditis

Background

Acute fulminant myocarditis in children is associated with elevated mortality and morbidity with few advances in its medical management. Here we report a preliminary experience of children treated with IL-1 receptor antagonist associated with rapid myocardial function recovery.

Methods

A retrospective case series of children admitted in the Pediatric Intensive Care Unit of the Bicêtre Hospital (AP–HP Paris Saclay University) between April 2020 and January 2022 with acute myocarditis. Children were treated with subcutaneous anakinra (an IL-1 receptor antagonist). Patients characteristics, and outcome are reported.

Results

Of 10 children admitted with acute fulminant myocarditis, eight were treated with sub-cutaneous anakinra. Seven children had SARS-CoV-2 post-infective myocarditis associated with multisystem inflammatory syndrome in children (MIS-C) and one child Parvovirus B19 myocarditis. In all patients a rapid (< 24 h) improvement in myocardial function was observed with concomitant decrease in myocardial enzymes. All patients survived with full myocardial recovery.

Conclusions

In this pilot study, use of IL-1 receptor antagonist in the initial treatment of acute fulminant myocarditis in children seems to be associated with rapid stabilization and recovery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-01054-0.

Findings and Outcome of Transcatheter Right Ventricular Endomyocardial Biopsy and Hemodynamic Assessment in Children with Suspected Myocarditis or Cardiomyopathy

OBJECTIVE

The study objective is assessing findings and outcome in children with suspected cardiomyopathy (CMP) or myocarditis undergoing cardiac catheterization with transcatheter right ventricular endomyocardial biopsy (RV-EMB).

METHODS

All consecutive children undergoing cardiac catheterization with RV-EMB for suspected CMP/myocarditis between 2002-2021 were analysed regarding clinical presentation, cardiac biomarkers, periprocedural management, hemodynamic, histological/immunohistological findings, and outcome.

RESULTS

Eighty-five RV-EMBs were performed in 81 patients at a median age of 6.8 (IQR 9.9) years and a bodyweight of 20 (32.2) kg. Histological/immunohistological findings of RV-EMB revealed dilated CMP in 10 (12%), chronic myocarditis in 28 (33%), healing myocarditis in 5 (6%), acute myocarditis in 9 (11%), other heart muscle diseases in 23 (27%) (7 restrictive CMP, 5 hypertrophic CMP, 4 toxic/anthracycline-induced CMP, 4 endocardfibroelastosis, 1 arrhythmogenic right ventricular CMP, 1 laminin CMP, 1 haemangioma), no conclusive histology in 7 (8%), and normal histology in 3 (4%) patients. Median LVEDP was 17 mmHg (IQR 9), LAP 15 mmHg (10), and PVR 1.83 (1.87) Wood Units/m². There were 3 major complications (3%), all patients recovered without any sequelae. At follow-up (median 1153, IQR 1799 days) 47 (59%) patients were alive, 11 (13%) dead, 15 (18%) underwent cardiac transplantation, and 8 (9%) were lost to follow-up. Death/cardiac transplantation occurred within 3 years from RV-EMB. All patients with an acute myocarditis survived. NT-pro-BNP, echo parameters, and invasive hemodynamics correlate independently with death/cardiac transplant.

CONCLUSION

Hemodynamic invasive data and morphological findings in RV-EMB complete clinical diagnosis in children with suspected CMP/myocarditis and provide important information for further clinical management.

Parametric Mapping Cardiac Magnetic Resonance Imaging for the Diagnosis of Myocarditis in Children in the Era of COVID-19 and MIS-C

Myocarditis comprises many clinical presentations ranging from asymptomatic to sudden cardiac death. The history, physical examination, cardiac biomarkers, inflammatory markers, and electrocardiogram are usually helpful in the initial assessment of suspected acute myocarditis. Echocardiography is the primary tool to detect ventricular wall motion abnormalities, pericardial effusion, valvular regurgitation, and impaired function. The advancement of cardiac magnetic resonance (CMR) imaging has been helpful in clinical practice for diagnosing myocarditis. A recent Scientific Statement by the American Heart Association suggested CMR as a confirmatory test to diagnose acute myocarditis in children. However, standard CMR parametric mapping parameters for diagnosing myocarditis are unavailable in pediatric patients for consistency and reliability in the interpretation. The present review highlights the unmet clinical needs for standard CMR parametric criteria for diagnosing acute and chronic myocarditis in children and differentiating dilated chronic myocarditis phenotype from idiopathic dilated cardiomyopathy. Of particular relevance to today’s practice, we also assess the potential and limitations of CMR to diagnose acute myocarditis in children exposed to severe acute respiratory syndrome coronavirus-2 infections. The latter section will discuss the multi-inflammatory syndrome in children (MIS-C) and mRNA coronavirus disease 19 vaccine-associated myocarditis.

Combination of Sophora flavescens alkaloids and Panax quinquefolium saponins modulates different stages of experimental autoimmune myocarditis via the NF‑κB and TGF‑β1 pathways

Chronic cardiac inflammation and fibrosis can progress into severe forms of cardiomyopathy. Sophora flavescens alkaloids (KuShen) have been previously reported to exert anti-inflammatory effects, whereas Panax quinquefolium saponins (XiYangShen) has been shown to alleviate cardiac fibrosis. Therefore, the potential effects of their combination (KX) on different stages of autoimmune myocarditis were investigated in the present study. Mice were randomly divided into the following four groups: Control; experimental autoimmune myocarditis (EAM); KX-High (275 mg/kg); and KX-Low (138 mg/kg). A 21-day and a 60-day EAM model was established through multi-site subcutaneous injections of cardiac myosin mixed with complete Freund's adjuvant on days 0, 7, 21 and 42. Mice in the High and Low KX groups were treated by gavage (10 ml/kg) daily from day 0 (1 day before treatment) until sacrifice (day 21 or 60). Mice in the control and EAM groups received an equivalent volume of distilled water. The levels of lactate dehydrogenase (LDH), creatine kinase-myocardial band (CK-MB), cardiac troponin I (cTn-I), IL-1β, IL-6, TNF-α, TGF-β1, collagen type I (Col Ⅰ) and collagen type III (Col Ⅲ) were measured by ELISA in the mouse myocardial tissues or serum. Myocardial tissue structure and extent of fibrosis were visualized using H&E and Masson's staining. Western blotting and immunohistochemistry were used to measure the expression levels NF-κB and TGF-β1 pathway proteins in the myocardial tissues. The degree of inflammation in the 21-day EAM model was found to be significantly higher compared with that in the 60-day EAM model. KX significantly reduced the inflammatory response at 21 days by decreasing the expression levels of CK-MB, LDH, cTn-I, IL-1β, IL-6, TNF-α and TGF-β-activated kinase 1-binding protein 1/NF-κB pathway proteins. Myocardial fibrosis in the 60-day EAM model was also significantly worse compared with that in the 21-day EAM model. However, fibrosis was significantly delayed by treatment with KX. In addition, KX significantly decreased the expression levels of TGF-β1, Smad2, Smad4, Col I and Col III. Therefore, these data suggest that KX is beneficial for treating myocarditis by targeting multiple pathways.

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 Review of Extraintestinal Manifestations & Medication-Induced Myocarditis and Pericarditis in Pediatric Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a systemic disorder where extraintestinal symptoms may involve virtually any organ system. Of these extraintestinal symptoms, those involving the heart are relatively rare but associated with significant morbidity. We reviewed the existing literature on noninfectious myocarditis and pericarditis in the pediatric IBD population, including extraintestinal manifestations (EIMs) of IBD and extraintestinal complications (EICs) from medication. We focused on the incidence, presentation, diagnosis, treatment, and outcomes for timely diagnosis and management of these potentially deadly diseases. In addition, we aim to identify and highlight the gaps in current knowledge for future studies and investigations.

Cardiovascular Abnormalities in Juvenile Dermatomyositis: A Scoping Review for the Clinical Rheumatologists

Juvenile dermatomyositis (JDM) is a common form of inflammatory myositis in children. Vasculopathy and endothelial dysfunction play significant roles in the pathogenesis of JDM. Cardiac involvement in JDM is often underestimated, and it may be a potential indicator of poor prognosis. Cardiac dysfunction in JDM can occur both in the acute and chronic stages of the disease. Amongst the acute complications, acute congestive heart failure (CHF), myocarditis, arrhythmia, and complete heart block are common. However, these remain unrecognized due to a lack of overt clinical manifestations. Increased rates of cardiovascular abnormalities have been noted with anti-SRP and anti-Jo 1 auto-antibody positivity. Long-term follow-up studies in JDM have shown an increased prevalence of hypertension, atherosclerosis, coronary artery disease, and metabolic syndrome in adolescence and adulthood. Monitoring of body-mass index, blood pressure, and laboratory evaluation of fasting glucose and lipid profile may help in identifying metabolic syndrome in children with JDM. Steroid-sparing agents, daily exercise, and a healthy diet may reduce such long-term cardiac morbidities. Current use of multimodality imaging such as stress-echocardiography, contrast-enhanced echocardiography, cardiac magnetic resonance imaging, and positron emission tomography has increased the diagnostic yield of subclinical heart disease during acute and chronic stages of JDM. This review elaborates on different aspects of cardiac dysfunction in JDM. It also emphasizes the importance of cardiac screening in long-term follow-up of children with JDM.

Electrocardiogram changes in pediatric patients with myocarditis

BACKGROUND

It is traditionally taught that pediatric patients with myocarditis almost always have an abnormal electrocardiogram (ECG) at presentation. However, there has never been a study to objectively evaluate ECG changes in pediatric myocarditis patients compared to healthy controls or explore if specific ECG changes correlate with clinical outcomes.

METHODS

Pediatric patients diagnosed with acute myocarditis were age and sex matched 1:2 with healthy controls in this retrospective case-control study spanning a seven-year period. ECGs from presentation through discharge were interpreted by electrophysiologists blinded to the patients' diagnoses.

RESULTS

Thirty-nine patients with myocarditis were identified. Twenty-eight (72%) had an abnormal ECG at presentation, 11 (28%) had a completely normal ECG. In this second group, six patients had an abnormal ECG at some point during their hospital course for a total of 34 (88%). Myocarditis patients who had an abnormal ECG at presentation spent more time in the hospital, 5 (2-19) versus 2 ((1-3) days (p < 0.01), and in the ICU, 1 (0-6) versus 0 (0-1) days (p < 0.01). Myocarditis patients were more likely to have ST elevation on their ECG compared to control patients (41% versus 17%, p < 0.01). Patients with ST elevation at presentation had a higher peak troponin level, 18.4 (5.8-31.0) versus 7.7 (0-19.1) ng/ml, (p < 0.01).

CONCLUSIONS

Over a quarter of patients with myocarditis had a normal ECG at presentation to the emergency department. Patients with an abnormal ECG at presentation spent more time in the hospital. The presenting ECG, particularly the presence of ST elevation, may correlate with other clinical markers and help direct early management decisions.

SARS-CoV-2 Associated Pediatric Inflammatory Multisystem Syndrome With a High Prevalence of Myocarditis - A Multicenter Evaluation of Clinical and Laboratory Characteristics, Treatment and Outcome

Introduction

Pediatric inflammatory multisystem syndrome - temporally associated with SARS-CoV-2 infection (PIMS -TS) comprises a new disease entity having emerged after the COVID-19 outbreak in 2019.

Materials and Methods

For this multicenter, retrospective study children between 0 and 18 years with PIMS-TS between March 2020 and May 2021 were included, before availability of vaccination for children. Frequent SARS-CoV-2 variants at that period were the wildtype virus, alpha, beta and delta variants. Inclusion criteria were according to the PIMS-TS criteria, proposed by the Royal College of Pediatrics and WHO. Study aim was to review their clinical, laboratory and echocardiographic data with a focus on cardiac involvement.

Results

We report 45 patients, median age 9 years, 64% male. SARS-CoV-2 antibodies were positive in 35/41 (85%). PIMS occurrence followed local COVID-19 peak incidence periods with a time lag. The most common symptoms at presentation were fever (98%), abdominal pain (89%) and rash (80%). Fever history of > 5 days was associated with decreased left ventricular function (p = 0.056). Arterial hypotension and cardiac dysfunction were documented in 72% patients, increased brain natriuretic peptide in 96% and increased cardiac troponin in 64% of the children. Echocardiography revealed mitral valve regurgitation (64%), coronary abnormalities (36%) and pericardial effusions (40%). Increased NT-proBNP was significantly associated with the need of inotropics (p < 0.05), which were necessary in 40% of the patients. Treatment comprised intravenous immunoglobulin (93%), systemic steroids (84%) and acetylsalicylic acid (100%; 26/45 started with high dosages). For insufficient response to this treatment, five (11%) children received the interleukin-1 receptor antagonist anakinra. All patients were discharged with almost resolved cardiac signs.

Conclusion

Our analysis of non-vaccinated children with PIMS-TS demonstrates that a considerable number have associated myocarditis requiring intensive care and inotropic support. Most children showed adequate response to intravenous immunoglobulin and steroids and good recovery. Further evaluation of pediatric patients with COVID-19 associated diseases is required to evaluate the impact of new virus variants.

Pediatric Myocarditis: What Have We Learnt So Far?

Myocarditis is an inflammatory disease of the myocardium that is troublesome to diagnose and manage, especially in children. Since the introduction of endomyocardial biopsy (EMB), new diagnostic tools have provided useful data. Especially when enhanced with immunohistochemistry and polymerase chain reaction (PCR) studies, EMB remains the gold standard for the diagnosis. Notably, cardiac magnetic resonance (MRI) is a non-invasive tool that can confirm the diagnosis and has a particular usefulness during the follow-up. The causes of myocarditis are heterogeneous (mostly viral in children). The course and outcome of the illness in the pediatric population represent a complex interaction between etiologic agents and the immune system, which is still not fully understood. The clinical presentation and course of myocarditis vary widely from paucisymptomatic illness to acute heart failure refractory to therapy, arrhythmias, angina-like presentation and sudden cardiac death. In this setting, cardiac biomarkers (i.e., troponins and BNP), although unspecific, can be used to support the diagnosis. Finally, the efficacy of therapeutic strategies is controversial and not confirmed by clinical trials. In this review, we summarized the milestones in diagnosis and provided an overview of the therapeutic options for myocarditis in children.

Comparison of Multisystem Inflammatory Syndrome in Children-Related Myocarditis, Classic Viral Myocarditis, and COVID-19 Vaccine-Related Myocarditis in Children

Background Although rare, classic viral myocarditis in the pediatric population is a disease that carries significant morbidity and mortality. Since 2020, myocarditis has been a common component of multisystem inflammatory syndrome in children (MIS-C) following SARS-CoV-2 infection. In 2021, myocarditis related to mRNA COVID-19 vaccines was recognized as a rare adverse event. This study aims to compare classic, MIS-C, and COVID-19 vaccine-related myocarditis with regard to clinical presentation, course, and outcomes. Methods and Results In this retrospective cohort study, we compared patients aged <21 years hospitalized at our institution with classic viral myocarditis from 2015 to 2019, MIS-C myocarditis from March 2020 to February 2021, and vaccine-related myocarditis from May 2021 to June 2021. Of 201 total participants, 43 patients had classic myocarditis, 149 had MIS-C myocarditis, and 9 had vaccine-related myocarditis. At presentation, ejection fraction was lowest for those with classic myocarditis, with ejection fraction <55% present in 58% of patients. Nearly all patients with MIS-C myocarditis (n=139, 93%) and all patients with vaccine-related myocarditis (n=9, 100%) had normal left ventricular ejection fraction at the time of discharge compared with 70% (n=30) of the classic myocarditis group (P<0.001). At 3 months after discharge, of the 21 children discharged with depressed ejection fraction, none of the 10 children with MIS-C myocarditis had residual dysfunction compared with 3 of the 11 (27%) patients in the classic myocarditis group. Conclusions Compared with classic myocarditis, those with MIS-C myocarditis had better clinical outcomes, including rapid recovery of cardiac function. Patients with vaccine-related myocarditis had prompt resolution of symptoms and improvement of cardiac function.

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.

Non-Cardiac Cause of Death in Selected Group Children with Cardiac Pathology: A Retrospective Single Institute Study

Background: Pediatricians and pediatric surgeons often face children with cardiomegaly and dilatative or hypertrophic cardiomyopathies presenting with or without symptoms. Some of these patients have already been diagnosed and received medication, and some present with completely unrelated pathologies. Methods: We performed a 4-year retrospective study on the causes and mechanisms of death of children with cardiac pathology who died outside the cardiology clinic of our hospital by studying the hospital charts and necropsy reports. All children who were in this situation in our hospital were included. Results: Most children in our study group were infants (81.82%), most were boys (81.82%), and in most cases, the cause or mechanism of death was unrelated to their heart condition, whether it had already been diagnosed or not (one case probably died as a result of a malignant ventricular arrhythmia). Additionally, 27.27% of children died as a consequence of bronchopneumonia, the same percentage died as a consequence of an acquired non-pulmonary disease or after surgery, and 18.18% died as a consequence of congenital malformations. Conclusions: Cardiac disease needs to be thoroughly investigated using multiple tools for all children presenting with heart failure symptoms, those with heart murmurs, and children scheduled for surgery of any type. The intensive care specialist and surgeon need to be aware of any heart pathology before non-cardiac surgical interventions.

Spectrum of Viral Pathogens Identified in Children with Clinical Myocarditis (Pre-Coronavirus Disease-2019, 2000-2018): Etiologic Agent Versus Innocent Bystander

OBJECTIVE

To identify the etiologies of viral myocarditis in children in the pre-coronavirus disease 2019 era.

STUDY DESIGN

This was a retrospective review of all patients (age <18 years) diagnosed with myocarditis and hospitalized at Rady Children's Hospital San Diego between 2000 and 2018.

RESULTS

Twenty-nine patients met inclusion criteria. Of 28 (97%) patients who underwent testing for viruses, polymerase chain reaction was used in 24 of 28 (86% of cases), and 16 of 24 (67%) detected a virus. Pathogens were rhinovirus (6), influenza A/B (4), respiratory syncytial virus (RSV) (3), coronavirus (3), parvovirus B19 (2), adenovirus (2), and coxsackie B5 virus, enterovirus, and parainfluenza virus type 2 in one case each. Six (21%) patients had no pathogen detected but imaging and other laboratory test results were compatible with myocarditis. Age 0-2 years was associated with RSV, influenza A/B, coronavirus, and enteroviruses (P < .001). Twenty-one patients (72%) experienced full clinical recovery. Three patients (10%) required venoarterial extracorporeal membrane oxygenation (VA-ECMO), and all 3 recovered. Three others (10%) required and underwent successful cardiac transplantation without complications. Two patients (7%) died 9-10 days after hospitalization (1 had RSV and 1 had influenza A/B). Two other patients presented with complete atrioventricular block; 1 case (rhinovirus) resolved spontaneously, and 1 (coronavirus) resolved after support with VA-ECMO. Age <2 years, female sex, lower ejection fraction at admission, and greater initial and peak levels of brain natriuretic peptide were significant predictors of critical outcomes (use of VA-ECMO, listing for cardiac transplantation, and death).

CONCLUSIONS

Viral nucleic acid-based testing revealed a wider spectrum of viruses that could be associated with myocarditis in children than previously reported and traditionally anticipated. A predilection of certain pathogens in the very young patients was observed. Whether the observed range of viral agents reflects an undercurrent of change in viral etiology or viral detection methods is unclear, but the wider spectrum of viral pathogens found underscores the usefulness of polymerase chain reaction testing to explore possible viral etiologies of myocarditis in children.

SARS-CoV-2 attacks the weakest point - COVID-19 course in a pediatric patient with Friedreich's ataxia

COVID-19 pandemic is the biggest epidemiological problem of the 21st century. The severe course of SARS-CoV-2 infection in children is rare. Sometimes, especially in patients with chronic disease, COVID-19 may be insidious and life-threatening. This article presents the course of COVID-19 in a 17-year-old boy with Friedreich's ataxia-induced hypertrophic cardiomyopathy. Despite that the main symptoms of COVID-19 (i.e., fever, cough) were moderate at the beginning of the illness, the patient condition deteriorated rapidly due to cardiac problems, atrial fibrillation, and heart failure. He required antiarrhythmic treatment and pharmacological and electrical cardioversion. Moreover, because of pneumonia requiring supplemental oxygen, remdesivir and convalescent plasma therapy were utilized in this patient. For the patient recovery, the administration of the antiviral treatment was crucial.

Advanced detection strategies for cardiotropic virus infection in a cohort study of heart failure patients

The prevalence and contribution of cardiotropic viruses to various expressions of heart failure are increasing, yet primarily underappreciated and underreported due to variable clinical syndromes, a lack of consensus diagnostic standards and insufficient clinical laboratory tools. In this study, we developed an advanced methodology for identifying viruses across a spectrum of heart failure patients. We designed a custom tissue microarray from 78 patients with conditions commonly associated with virus-related heart failure, conditions where viral contribution is typically uncertain, or conditions for which the etiological agent remains suspect but elusive. Subsequently, we employed advanced, highly sensitive in situ hybridization to probe for common cardiotropic viruses: adenovirus 2, coxsackievirus B3, cytomegalovirus, Epstein-Barr virus, hepatitis C and E, influenza B and parvovirus B19. Viral RNA was detected in 46.4% (32/69) of heart failure patients, with 50% of virus-positive samples containing more than one virus. Adenovirus 2 was the most prevalent, detected in 27.5% (19/69) of heart failure patients, while in contrast to previous reports, parvovirus B19 was detected in only 4.3% (3/69). As anticipated, viruses were detected in 77.8% (7/9) of patients with viral myocarditis and 37.5% (6/16) with dilated cardiomyopathy. Additionally, viruses were detected in 50% of patients with coronary artery disease (3/6) and hypertrophic cardiomyopathy (2/4) and in 28.6% (2/7) of transplant rejection cases. We also report for the first time viral detection within a granulomatous lesion of cardiac sarcoidosis and in giant cell myocarditis, conditions for which etiological agents remain unknown. Our study has revealed a higher than anticipated prevalence of cardiotropic viruses within cardiac muscle tissue in a spectrum of heart failure conditions, including those not previously associated with a viral trigger or exacerbating role. Our work forges a path towards a deeper understanding of viruses in heart failure pathogenesis and opens possibilities for personalized patient therapeutic approaches.

Clinically Suspected Myocarditis Temporally Related to COVID-19 Vaccination in Adolescents and Young Adults

BACKGROUND

Understanding the clinical course and short-term outcomes of suspected myocarditis following COVID-19 vaccination has important public health implications in the decision to vaccinate youth.

METHODS

We retrospectively collected data on patients <21 years-old presenting before 7/4/2021 with suspected myocarditis within 30 days of COVID-19 vaccination. Lake Louise criteria were used for cardiac magnetic resonance imaging (cMRI) findings. Myocarditis cases were classified as confirmed or probable based on the Centers for Disease Control and Prevention definitions.

RESULTS

We report on 139 adolescents and young adults with 140 episodes of suspected myocarditis (49 confirmed, 91 probable) at 26 centers. Most patients were male (N=126, 90.6%) and White (N=92, 66.2%); 29 (20.9%) were Hispanic; and median age was 15.8 years (range 12.1-20.3, IQR 14.5-17.0). Suspected myocarditis occurred in 136 patients (97.8%) following mRNA vaccine, with 131 (94.2%) following the Pfizer-BioNTech vaccine; 128 (91.4%) occurred after the 2nd dose. Symptoms started a median of 2 days (range 0-22, IQR 1-3) after vaccination. The most common symptom was chest pain (99.3%). Patients were treated with nonsteroidal anti-inflammatory drugs (81.3%), intravenous immunoglobulin (21.6%), glucocorticoids (21.6%), colchicine (7.9%) or no anti-inflammatory therapies (8.6%). Twenty-six patients (18.7%) were in the ICU, two were treated with inotropic/vasoactive support, and none required ECMO or died. Median hospital stay was 2 days (range 0-10, IQR 2-3). All patients had elevated troponin I (N=111, 8.12 ng/mL, IQR 3.50-15.90) or T (N=28, 0.61 ng/mL, IQR 0.25-1.30); 69.8% had abnormal electrocardiograms and/or arrythmias (7 with non-sustained ventricular tachycardia); and 18.7% had left ventricular ejection fraction (LVEF) <55% on echocardiogram. Of 97 patients who underwent cMRI at median 5 days (range 0-88, IQR 3-17) from symptom onset, 75 (77.3%) had abnormal findings: 74 (76.3%) had late gadolinium enhancement, 54 (55.7%) had myocardial edema, and 49 (50.5%) met Lake Louise criteria. Among 26 patients with LVEF <55% on echocardiogram, all with follow-up had normalized function (N=25).

CONCLUSIONS

Most cases of suspected COVID-19 vaccine myocarditis occurring in persons <21 years have a mild clinical course with rapid resolution of symptoms. Abnormal findings on cMRI were frequent. Future studies should evaluate risk factors, mechanisms, and long-term outcomes.

Myopericarditis After the Pfizer Messenger Ribonucleic Acid Coronavirus Disease Vaccine in Adolescents

Reports have emerged of myocarditis and pericarditis predominantly after the second dose of the coronavirus disease messenger ribonucleic acid vaccine. We describe 13 patients aged 12-17 years who presented with chest pain within 1 week after their second dose of the Pfizer vaccine and were found to have elevated serum troponin levels and evidence of myopericarditis.

Arrhythmia spectrum and outcome in children with myocarditis

Introduction

Myocarditis remains an under-diagnosed entity among children. We evaluated the spectrum of electrocardiogram (ECG) changes and arrhythmias in children with myocarditis.

Methods

A single-center prospective observational study was conducted over a period of 18 months at a public university hospital, which included all cases with myocarditis from the ages of 1 month to 12 years. Myocarditis was diagnosed according to standard criteria. Arrhythmias were detected by 12-lead ECG or by multiparameter monitors.

Results

There were 63 children with myocarditis. Sinus tachycardia remained the most important ECG finding (61, 96.8%) followed by ST-T changes (30, 47.6%), low voltage QRS complexes (23, 36.5%), and premature complexes (11, 17.4%). Sustained arrhythmias were seen in 14/63 (22.2%) of the children (Group A), while the remaining 49 patients were designated as Group B. There were 11 (17.5%) cases with sustained tachyarrhythmias, comprising 5 with supraventricular tachycardia, 4 with ventricular tachycardia, and 2 with atrial flutter/fibrillation. Bradyarrhythmias were seen in 3 patients, including 2 children with atrioventricular block and 1 with severe sinus bradycardia. A longer hospital stay of 18.5 (4.75) days vs. 13 (4) days, P = 0.001), and more ST-T changes [12 (85.7%) vs. 18 (36.73%), P = 0.003] were seen in Group A. Multivariate regression analysis found only the presence of ST-T changes as predictors for arrhythmia.

Conclusions

A variety of arrhythmias and other ECG changes were commonly seen in children with myocarditis. Sustained arrhythmias were seen in one-fifth of the patients, being associated with ST-T changes and a longer hospital stay.

Challenges of Diagnosing Viral Myocarditis in Adolescents in the Era of COVID-19 and MIS-C

Myocarditis has a wide array of clinical presentations ranging from asymptomatic to sudden cardiac death. Pediatric myocarditis is a rare disease, with an estimated annual incidence of 1 to 2 per 100,000 children though its true prevalence remains unknown due to its variable and often subclinical presentation. The diagnosis of myocarditis is challenging in the era of COVID-19 and Multisystem Inflammatory Syndrome in Children (MIS-C), which can have overlapping clinical conundrum. Here, we present a case of a 17-year-old male presenting with chest tightness, shortness of breath, and electrocardiogram (EKG) findings concerning for myocardial injury along with elevated inflammatory markers such as D-dimer, ESR (Erythrocyte Sedimentation Rate), and CRP (C-Reactive Protein). We discuss the key elements of our clinical experience with this case and review the literature for pediatric myocarditis, with a focus on differentiating it from MIS-C in the current COVID-19 pandemic era.