Occurrence and Features of Childhood Myocarditis: A Nationwide Study in Finland

Acute myocarditis according to age: Presentation, management and early outcomes

AIMS

Acute myocarditis (AM) is a rare but severe disease affecting patients of all ages. Large multicentric studies comparing children and adults are currently lacking. We aimed to elucidate differences in presentation, management, and outcomes of AM across age groups.

METHODS

We analysed a comprehensive French national cohort study, encompassing 53 paediatric and adult units from March 2020 to November 2021, collecting data on baseline characteristics, evolution, management and in-hospital complications. Myocarditis-related events (MRE) within 30 days included all-cause death, cardiogenic shock, cardiac arrest, ventricular arrhythmias or complete AV block.

RESULTS

We included 745 AM patients (328 children and 417 adults), mainly male (73.4%) with a median age of 10.9 years [Q1-Q3 (7.3-14.6)] for children and 28.7 years [22.6-41.2] for adults. Multisystem inflammatory syndrome (MIS) was more prevalent among children (69.8%), and infectious aetiologies dominated in adults (13.4 vs. 52.4%). Children exhibited more severe clinical presentation (15.9 vs. 7.2%, P < 0.001, with heart failure and 14.4 vs. 6.9%, P < 0.001, with cardiogenic shock), requiring higher use of inotropes (25.0 vs. 9.4%, P < 0.001), vasopressors (12.0 vs. 6.2%, P < 0.001), and ventilatory support (13.7% vs. 7.9%, P = 0.01). Cardiac treatments were used less frequently in children, and corticosteroids (68.3 vs, 14.3, P < 0.001) and immunomodulators (65.1 vs. 4.5%, P < 0.001) were more common. MRE occurrence was substantial but not significantly different between children and adults (18.1 vs. 13.4%, P = 0.09). Extra-cardiac manifestations at admission were significant predictors of MRE [adjusted odds ratio 2.40 (1.43-4.38)], regardless of MIS status.

CONCLUSIONS

AM exhibits variations in presentation, aetiologies and management but has a comparable 30 day prognosis in children and adults. These findings underscore the importance of tailored management strategies in AM across different age groups.

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.

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.

The global, regional, and national burden of myocarditis in 204 countries and territories, 1990-2021: Results from the Global Burden of Disease Study 2021

AIMS

To estimate the global burden of myocarditis in the general population from 1990 to 2021.

METHODS AND RESULTS

Data on myocarditis were retrieved from the Global Burden of Disease Study 2021. Incidence, deaths, and disability-adjusted life years (DALYs), along with their age-standardized rates (ASRs) per 100 000 population, were used to measure the burden of myocarditis. Global, regional, and national analyses were performed for the period between 1990 and 2021. Further sub-analyses were conducted based on age group, sex, and sociodemographic index (SDI). In 2021, there were 1.3 million (95% uncertainty interval [UI]: 1.1 to 1.6) incident cases, 31.7 thousand (95% UI: 25.5 to 37.1) deaths, and 96.3 thousand (95% UI: 79.6 to 114.8) DALY cases globally. The ASRs of incidence, death, and DALYs significantly decreased from 1990 to 2021, with percentage changes of -3.9% (95% UI: -4.7% to -2.9%), -28.2% (95% UI: -42.2% to -12.5%), and -37.8% (95% UI: -50.5% to -24.3%), respectively. The global burden of myocarditis was higher in males, children, and the elderly. Additionally, the burden of myocarditis varied widely across different SDI regions, with high SDI regions having the highest ASR of incidence, and high-middle SDI regions having the highest ASRs of deaths and DALYs.

CONCLUSION

Although the ASRs of incidence, deaths, and DALYs significantly decreased from 1990 to 2021, the global number of incidences, deaths, and DALYs increased substantially. Certain populations, including males, children, the elderly, and regions with advanced sociodemographic levels, experienced a heavier burden of myocarditis.

Prognostic Value of Speckle Tracking Echocardiography-Derived Strain in Unmasking Risk for Arrhythmias in Children with Myocarditis

Background/Objectives: Risk assessment in pediatric myocarditis is challenging, particularly when left ventricular ejection fraction (LVEF) is preserved. This study aimed to evaluate LV myocardial deformation using speckle-tracking echocardiography (STE)-derived longitudinal +strain (LS) and assessed its diagnostic and prognostic value in children with myocarditis. Methods: Retrospective STE-derived layer-specific LV LS analysis was performed on echocardiograms from patients within the multicenter, prospective registry for pediatric myocarditis "MYKKE". Age- and sex-adjusted logistic regression and ROC analysis identified predictors of cardiac arrhythmias (ventricular tachycardia, ventricular fibrillation, atrioventricular blockage III°) and major adverse cardiac events (MACE: need for mechanical circulatory support (MCS), cardiac transplantation, and/or cardiac death). Results: Echocardiograms from 175 patients (median age 15 years, IQR 7.9-16.5 years; 70% male) across 13 centers were included. Cardiac arrhythmias occurred in 36 patients (21%), and MACE in 28 patients (16%). Impaired LV LS strongly correlated with reduced LVEF (r > 0.8). Impaired layer-specific LV LS, reduced LVEF, LV dilatation, and increased BSA-indexed LV mass, were associated with the occurrence of MACE and cardiac arrhythmias. In patients with preserved LVEF, LV LS alone predicted cardiac arrhythmias (p < 0.001), with optimal cutoff values of -18.0% for endocardial LV LS (sensitivity 0.69, specificity 0.94) and -17.0% for midmyocardial LV LS (sensitivity 0.81, specificity 0.75). Conclusions: In pediatric myocarditis, STE-derived LV LS is not only a valuable tool for assessing systolic myocardial dysfunction and predicting MACE but also identifies patients at risk for cardiac arrhythmias, even in the context of preserved LVEF.

Myopericarditis following COVID-19 vaccination in children: a systematic review and meta-analysis

INTRODUCTION

Myopericarditis is a rare but serious coronavirus disease 2019 (COVID-19) vaccine-related adverse event primarily affecting adolescents. Given recent approvals for childhood vaccination, we performed a meta-analysis investigating myopericarditis following messenger ribonucleic acid COVID-19 vaccination in children aged <19 years, focusing on its overall risk and high-risk subgroups.

METHODS

We searched MEDLINE via PubMed, Embase and Scopus from inception to 1 August 2022 for observational studies reporting myopericarditis in temporal relation to paediatric COVID-19 vaccination. We conducted random-effects meta-analyses (DerSimonian and Laird) on myopericarditis (primary outcome), myocarditis and pericarditis (secondary outcomes).

RESULTS

Of 2115 studies, 12 (59,229,160 doses) studies were included in our analysis. There were 19.8 (95% confidence interval [CI]: 10.4-37.6) myopericarditis cases reported per million doses in children, compared to 23.7 (95% CI: 12.2-46.1) cases in adults (eight studies, 376,899,888 doses; P = 0.70). Compared to the second dose (34.4, 95% CI: 15.2-77.8), the number of cases post-first dose was significantly lower (9.1, 95% CI: 4.4-18.8; P = 0.017), while the number of cases post-third dose was not higher than that of post-second dose (28.4, 95% CI: 10.4-61.8; P = 0.57, global P = 0.031). Males were at higher risk of myopericarditis (67.4, 95% CI: 36.5-124.5) than females (6.9, 95% CI: 3.1-15.3; P < 0.0001). Finally, the number of cases was higher (overall P < 0.0001) among children aged ≥12 years (39.9, 95% CI: 24.1-66.0) than among children aged <12 years (3.0, 95% CI: 2.3-3.9).

CONCLUSION

Our meta-analysis showed 19.8 cases of myopericarditis per million doses among children, not significantly different from that of adults. Higher risk subgroups included adolescents, males, and those receiving their second dose of vaccination.

The Role of Magnetic Resonance Imaging in Risk Stratification of Patients with Acute Myocarditis

BACKGROUND

Cardiac magnetic resonance (cMRI) is often used to diagnose acute myocarditis (AM). It is also performed after 6 months to monitor myocardial involvement. However, the clinical and predictive relevance of the 6-month cMRI is uncertain.

OBJECTIVE

We used cMRI to assess the morphology and heart function of patients with AM, the correlation between left ventricular remodeling and biomarkers of heart dysfunction and myocardial fibrosis, and the involvement of myocardial fibrosis initially and 6 months after the acute episode.

MATERIALS AND METHODS

We conducted a prospective study of 90 patients with the clinical suspicion of AM, where cMRI was performed within the first week after symptom onset and repeated after 6 months.

RESULTS

Non-ischemic late gadolinium enhancement (LGE) was present in 88 (97.7%) patients and mainly involved the septum and inferior wall. cMRI at 6 months was associated with significantly reduced abnormalities of segmental kinetics (p < 0.001), myocardial edema (p < 0.001), presence of LGE (p < 0.05) and LGE mass (p < 0.01), native T1 mapping (p < 0.001), and presence of pericardial collection (p ≤ 0.001). At 6 months, signs of myocardial edema appeared in 34.4% of patients, and a complete cure (absence of edema and LGE) was found in 8.8% of patients. LGE disappeared in 15.2% of patients, and the mean number of myocardial segments involved decreased from 46% to 30%, remaining unchanged in 13% of patients. Patients with LGE without edema had a more severe prognostic condition than those with persistent edema. Patients with increased LGE extension on the control cMRI had a worse prognosis than those with modified or low LGE. The most significant independent predictive parameters for major cardiovascular events (MACEs) were LGE mass (adjusted OR = 1.27 [1.11-1.99], p < 0.001), myocardial edema (OR = 1.70 [1.14-209.3], p < 0.001), and prolonged native T1 (OR = 0.97 [0.88-3.06], p < 0.001). The mid-wall model of LGE and the presence of edema-free LGE were MACE-independent predictors.

CONCLUSIONS

LGE, myocardial edema, and prolonged native T1 were predictors of MACEs. LGE does not necessarily mean constituted fibrosis in the presence of edema and may disappear over time. LGE without edema could represent fibrosis, whereas the persistence of edema represents active inflammation and could be associated with the residual chance of complete recovery. cMRI should be performed in all patients with AM at 6 months to evaluate progress and prognosis.

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.

Soluble suppression of tumorigenicity 2 associated with major adverse cardiac events in children with myocarditis

Objective

Soluble suppression of tumorigenicity 2 (sST2) is associated with the prognosis of some cardiac diseases, but studies on sST2 and the prognosis of patients with myocarditis are rare. This study investigated the relationship between major adverse cardiovascular events (MACEs) and sST2 during hospitalization in pediatric patients with myocarditis.

Methods

This was a single-center retrospective cohort study. A total of 252 patients aged ≤14 years diagnosed with myocarditis were enrolled. Events during the hospitalization were defined as MACEs (all-cause death > new heart failure > ventricular arrhythmia).

Results

A total of 25 people had MACEs during their hospital stay. The mortality during hospitalization was 6/23 (26%) in patients with heart failure and 3/10 (30%) in patients with ventricular arrhythmias. After including these risk factors in a multivariate logistic regression analysis, NT-proBNP (OR 4.323; 95% CI, 2.433-7.679; p < 0.001) and sST2 (OR 1.020; 95% CI, 1.003-1.037; p = 0.022) remained statistically significant and were independent risk factors for MACEs during hospitalization in pediatric myocarditis patients.

Conclusions

Elevated levels of NT-proBNP and sST2 were independently associated with major adverse cardiovascular events during hospitalization in children with myocarditis, and both showed good predictive efficacy.

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.

Myocarditis and pericarditis risk with mRNA COVID-19 vaccination compared to unvaccinated individuals: A retrospective cohort study in a Spanish Tertiary Hospital

OBJECTIVE

This study compared the incidence of pericarditis and myocarditis in patients exposed to mRNA COVID-19 vaccines to the incidence in those who were not vaccinated, considering the incidence of these conditions resulting from COVID-19 infection.

METHODS

This was a retrospective cohort study of individuals assigned to health area of La Paz University Hospital in Spain. The exposure factor was vaccination with mRNA COVID-19 vaccines between December 27th, 2020 and January 9th, 2022 with a minimum follow-up of one month. The outcome was the incidence of pericarditis or myocarditis in these individuals.

RESULTS

The incidence of pericarditis and myocarditis in the total population exposed to at least one dose of mRNA COVID-19 vaccines was 5/100,000 (CI95%:3 to 8 per 100,000), compared to 70/100,000 (CI95%: 66 to 92 per 100,000) in those who were not vaccinated. In the adolescent population (aged 12-17), the incidence was 10/100,000 in vaccinated population (CI95%: 5 to 45 per 100,000) compared to 20/100,000 in unvaccinated (CI95%: 6 to 79 per 100,000). The incidence of pericarditis or myocarditis in patients with COVID-19 infection was 200/100,000 people (CI95%: 114 to 306 per 100,000). The most common cause of pericarditis and myocarditis in the cohort was idiopathic/infectious (74 cases). Cases of myocarditis attributed to COVID-19 infection were more severe and had higher mortality rates compared to cases with other causes.

CONCLUSION

The incidence of pericarditis and myocarditis in patients exposed to mRNA COVID-19 vaccines was lower than in those who were not vaccinated, especially in adults.The most common cause of pericarditis and myocarditis was idiopathic/infectious, but the most frequent cause in adolescent patients was mRNA COVID-19 vaccination. Cases of myocarditis due to COVID-19 infection were more severe and had greater mortality.

Update on Myocarditis: From Etiology and Clinical Picture to Modern Diagnostics and Methods of Treatment

Although the frequency of myocarditis in the general population is very difficult to accurately determine due to the large number of asymptomatic cases, the incidence of this disease is increasing significantly due to better defined criteria for diagnosis and the development of modern diagnostic methods. The multitude of different etiological factors, the diversity of the clinical picture, and the variability of the diagnostic findings make this disease often demanding both for the selection of the diagnostic modality and for the proper therapeutic approach. The previously known most common viral etiology of this disease is today overshadowed by new findings based on immune-mediated processes, associated with diseases that in their natural course can lead to myocardial involvement, as well as the iatrogenic cause of myocarditis, which is due to use of immune checkpoint inhibitors in the treatment of cancer patients. Suspecting that a patient with polymorphic and non-specific clinical signs and symptoms, such as changes in ECG and echocardiography readings, has myocarditis is the starting point in the diagnostic algorithm. Cardio magnetic resonance imaging is non-invasive and is the gold standard for diagnosis and clinical follow-up of these patients. Endomyocardial biopsy as an invasive method is the diagnostic choice in life-threatening cases with suspicion of fulminant myocarditis where the diagnosis has not yet established or there is no adequate response to the applied therapeutic regimen. The treatment of myocarditis is increasingly demanding and includes conservative methods of treating heart failure, immunomodulatory and immunospressive therapy, methods of mechanical circulatory support, and heart transplantation. The goal of developing new diagnostic and therapeutic methods is to reduce mortality from this complex disease, which is still high.

Adverse Events Following the BNT162b2 mRNA COVID-19 Vaccine (Pfizer-BioNTech) in Aotearoa New Zealand

INTRODUCTION

In February 2021, New Zealand began its largest ever immunisation programme with the BNT162b2 mRNA coronavirus disease 2019 (COVID-19) vaccine.

OBJECTIVE

We aimed to understand the association between 12 adverse events of special interest (AESIs) and a primary dose of BNT162b2 in the New Zealand population aged ≥5 years from 19 February 2021 through 10 February 2022.

METHODS

Using national electronic health records, the observed rates of AESIs within a risk period (1-21 days) following vaccination were compared with the expected rates based on background data (2014-2019). Standardised incidence ratios (SIRs) were estimated for each AESI with 95% confidence intervals (CIs) using age group-specific background rates. The risk difference was calculated to estimate the excess or reduced number of events per 100,000 persons vaccinated in the risk period.

RESULTS

As of 10 February 2022, 4,277,163 first doses and 4,114,364 second doses of BNT162b2 had been administered to the eligible New Zealand population aged ≥5 years. The SIRs for 11 of the 12 selected AESIs were not statistically significantly increased post vaccination. The SIR (95% CI) for myo/pericarditis following the first dose was 2.3 (1.8-2.7), with a risk difference (95% CI) of 1.3 (0.9-1.8), per 100,000 persons vaccinated, and 4.0 (3.4-4.6), with a risk difference of 3.1 (2.5-3.7), per 100,000 persons vaccinated following the second dose. The highest SIR was 25.6 (15.5-37.5) in the 5-19 years age group, following the second dose of the vaccine, with an estimated five additional myo/pericarditis cases per 100,000 persons vaccinated. A statistically significant increased SIR of single organ cutaneous vasculitis (SOCV) was also observed following the first dose of BNT162b2 in the 20-39 years age group only.

CONCLUSIONS

A statistically significant association between BNT162b2 vaccination and myo/pericarditis was observed. This association has been confirmed internationally. BNT162b2 was not found to be associated with the other AESIs investigated, except for SOCV following the first dose of BNT162b2 in the 20-39 years age group only, providing reassurances around the safety of the vaccine.

Cardiovascular manifestations of inflammatory bowel diseases and the underlying pathogenic mechanisms

Inflammatory bowel disease (IBD), consisting of ulcerative colitis and Crohn's disease, mainly affects the gastrointestinal tract but is also known to have extraintestinal manifestations because of long-standing systemic inflammation. Several national cohort studies have found that IBD is an independent risk factor for the development of cardiovascular disorders. However, the molecular mechanisms by which IBD impairs the cardiovascular system are not fully understood. Although the gut-heart axis is attracting more attention in recent years, our knowledge of the organ-to-organ communication between the gut and the heart remains limited. In patients with IBD, upregulated inflammatory factors, altered microRNAs and lipid profiles, as well as dysbiotic gut microbiota, may induce adverse cardiac remodeling. In addition, patients with IBD have a three- to four times higher risk of developing thrombosis than people without IBD, and it is believed that the increased risk of thrombosis is largely due to increased procoagulant factors, platelet count/activity, and fibrinogen concentration, in addition to decreased anticoagulant factors. The predisposing factors for atherosclerosis are present in IBD and the possible mechanisms may involve oxidative stress system, overexpression of matrix metalloproteinases, and changes in vascular smooth muscle phenotype. This review focuses mainly on 1) the prevalence of cardiovascular diseases associated with IBD, 2) the potential pathogenic mechanisms of cardiovascular diseases in patients with IBD, and 3) adverse effects of IBD drugs on the cardiovascular system. Also, we introduce here a new paradigm for the gut-heart axis that includes exosomal microRNA and the gut microbiota as a cause for cardiac remodeling and fibrosis.

Do COVID-19 viral infection and its mRNA vaccine carry an equivalent risk of myocarditis? Review of the current evidence, insights, and future directions

According to recent epidemiological analysis, the percentage of world population infected with COVID-19 by end of December 2020 is approximately 12.56%1. COVID induced acute care and ICU hospitalization rates are around 9.22 (95% CI: 18.73-19.51), and 4.14 (95% CI: 4.10-4.18) per 1000 population1. Although therapeutic strategies such as antivirals, intravenous immunoglobulins and corticosteroids have shown modest efficacy in reducing the disease progression, they are not disease specific and only temper the immune mediated attack on the systemic tissues. Therefore, clinicians started to rely on mRNA COVID-19 vaccines, which are clinically efficacious in reducing the incidence, disease severity and systemic complications of COVID-19 infections. Nevertheless, usage of COVID-19 mRNA vaccines is also associated with cardiovascular complications such as myocarditis and pericarditis. On the other hand, COVID-19 infections itself are associated with cardiovascular complications such as myocarditis. The underlying signaling pathways for occurrence of COVID-19 and mRNA COVID-19 vaccine induced myocarditis are quite different although there is some overlap in autoimmunity and cross reactivity mechanisms. With media reports highlighting the cardiovascular complications of COVID-19 vaccines such as myocarditis, general population have become more hesitant and uncertain regarding the safety and efficacy of these mRNA vaccines. We plan to review the current literature and provide insights into their pathophysiological mechanisms for myocarditis and offer recommendations for further research studies in this regard. This will hopefully dispel some doubts and encourage more people to be vaccinated for preventing the risk of COVID-19 induced myocarditis and other associated cardiovascular complications.

Quantitative cardiac MRI parameters for assessment of myocarditis in children and adolescents: a systematic review and meta-analysis

AIM

To evaluate the role of quantitative cardiac magnetic resonance imaging (CMRI) parameters in myocarditis, including acute and chronic myocarditis (AM and CM), for children and adolescents.

MATERIALS AND METHODS

PRISMA principles were followed. PubMed, EMBASE, Web of Science, Cochrane Library, and grey literature were searched. The Newcastle-Ottawa Scale (NOS) and the Agency for Healthcare Research and Quality (AHRQ) checklist were utilised for quality assessment. Quantitative CMRI parameters were extracted and a meta-analysis was performed in comparison with healthy controls. The overall effect size was measured as the weighted mean difference (WMD).

RESULTS

Ten quantitative CMRI parameters of seven studies were analysed. Compared with the control group, the myocarditis group reported longer native T1 relaxation time (WMD=54.00, 95% confidence interval [CI]: 33.21,74.79, p<0.001), longer T2 relaxation time (WMD=2.13, 95% CI: 0.98, 3.28, p<0.001), increased extracellular volume (ECV; WMD=3.13, 95% CI: 1.34,4.91, p=0.001), elevated early gadolinium enhancement (EGE) ratio (WMD=1.47, 95% CI: 0.65,2.28, p<0.001), and increased T2-weighted ratio (WMD=0.43, 95% CI: 0.21,0.64, p<0.001). The AM group had longer native T1 relaxation times (WMD=72.02, 95% CI: 32.78,111.27, p<0.001), increased T2-weighted ratios (WMD=0.52, 95% CI: 0.21,0.84 p=0.001), and impaired left ventricular ejection fractions (LVEF; WMD=-5.84, 95% CI: -9.69, -1.99, p=0.003). Impaired LVEF (WMD=-2.24, 95% CI: -3.32, -1.17, p<0.001) was observed in the CM group.

CONCLUSION

Statistical differences can be observed in some CMRI parameters between patients with myocarditis and healthy controls; however, apart from native T1 mapping, there were no large differences in other parameters between two groups, which may reveal the limited benefit of CMRI in assessing myocarditis in children and adolescents.

COVID-19 Vaccines and Myocarditis: An Overview of Current Evidence

COVID-19 vaccines have been widely used to reduce the incidence and disease severity of COVID-19. Questions have lately been raised about the possibility of an association between COVID-19 vaccines and myocarditis, an inflammatory condition affecting the myocardium, or the middle layer of the heart. Myocarditis can be caused by infections, immune reactions, or toxic exposure. The incidence rate of myocarditis and pericarditis was calculated to be 5.98 instances per million COVID-19 vaccine doses delivered, which is less than half of the incidences after SARS-CoV-2 infection. Myocarditis rates in people aged 12 to 39 years are around 12.6 cases per million doses following the second dose of mRNA vaccination. Adolescent men are more likely than women to develop myocarditis after receiving mRNA vaccines. The objectives of this systematic review and meta-analysis are to find out how often myocarditis occurs after receiving the COVID-19 vaccine, as well as the risk factors and clinical repercussions of this condition. Nevertheless, the causal relationship between vaccination and myocarditis has been difficult to establish, and further research is required. It is also essential to distinguish between suggested cases of myocarditis and those confirmed by endomyocardial biopsy.

Leitlinie Myokarditis der Deutschen Gesellschaft für Pädiatrische Kardiologie

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

Assessment of Efficacy and Safety of mRNA COVID-19 Vaccines in Children Aged 5 to 11 Years: A Systematic Review and Meta-analysis

Importance

Evidence of the efficacy and safety of messenger RNA (mRNA) COVID-19 vaccines in children aged 5 to 11 years has been emerging. Collecting these data will inform clinicians, families, and policy makers.

Objective

To evaluate the efficacy and safety of mRNA COVID-19 vaccines in children aged 5 to 11 years in a systematic review and meta-analysis.

Data Sources

PubMed and Embase databases were searched on September 29, 2022, without language restrictions.

Study Selection

Randomized clinical trials and observational studies comparing vaccinated vs unvaccinated children aged 5 to 11 years and reporting efficacy or safety outcomes were included. Studies reporting safety outcomes in vaccinated children only (ie, no control group) were also included.

Data Extraction and Synthesis

Two investigators independently extracted relevant data from each study. Odds ratios (ORs) for efficacy and safety outcomes and incidences of adverse events (AEs) following vaccination were synthesized using a random-effects model. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses and Meta-analysis of Observational Studies in Epidemiology reporting guidelines.

Main Outcomes and Measures

The primary outcome was SARS-CoV-2 infections with or without symptoms. The secondary outcomes included symptomatic SARS-CoV-2 infections, hospitalizations, and multisystem inflammatory syndrome in children. The incidences of each AE following vaccination were also evaluated.

Results

Two randomized clinical trials and 15 observational studies involving 10 935 541 vaccinated children (median or mean age range, 8.0-9.5 years) and 2 635 251 unvaccinated children (median or mean age range, 7.0-9.5 years) were included. Two-dose mRNA COVID-19 vaccination compared with no vaccination was associated with lower risks of SARS-CoV-2 infections with or without symptoms (OR, 0.47; 95% CI, 0.35-0.64), symptomatic SARS-CoV-2 infections (OR, 0.53; 95% CI, 0.41-0.70), hospitalizations (OR, 0.32; 95% CI, 0.15-0.68), and multisystem inflammatory syndrome in children (OR, 0.05; 95% CI, 0.02-0.10). Two randomized clinical trials and 5 observational studies investigated AEs among vaccinated children. Most vaccinated children experienced at least 1 local AE following the first injection (32 494 of 55 959 [86.3%]) and second injection (28 135 of 46 447 [86.3%]). Vaccination was associated with a higher risk of any AEs compared with placebo (OR, 1.92; 95% CI, 1.26-2.91). The incidence of AEs that prevented normal daily activities was 8.8% (95% CI, 5.4%-14.2%) and that of myocarditis was estimated to be 1.8 per million (95% CI, 0.000%-0.001%) following the second injection.

Conclusions and Relevance

In this systematic review and meta-analysis, COVID-19 mRNA vaccines among children aged 5 to 11 years were associated with measures of efficacy in preventing SARS-CoV-2 infection and severe COVID-19-related illnesses. While most children developed local AEs, severe AEs were rare, and most of AEs resolved within several days. These data provide evidence for future recommendations.

Paediatric safety assessment of BNT162b2 vaccination in a multistate hospital-based electronic health record system in the USA: a retrospective analysis

BACKGROUND

The emergency use authorisation of BNT162b2 (tozinameran; Comirnaty, Pfizer-BioNTech) for children aged 5-17 years has resulted in rapid vaccination in the paediatric population. However, there are few studies of adverse events associated with vaccination in children. The aim of this study was to systematically assess the adverse events of two-dose BNT162b2 vaccination in the paediatric population.

METHODS

We conducted a retrospective analysis of patient electronic health records (EHRs) of children aged 5-17 years who received the primary two-dose series of the BNT162b2 vaccine between Jan 5, 2021, and Aug 5, 2022, at the Mayo Clinic Health System (MN, FL, AZ, IA, and WI), USA. Using natural language processing, we automatically curated adverse events reported by physicians in EHR clinical notes before and after vaccination. To determine significant adverse events after BNT162b2 vaccination, we calculated risk differences, which was defined as the percentage difference between the rate of children with an adverse event after a vaccine dose and the baseline rate of children with an adverse event before vaccination. 95% CIs and p values were calculated using the Miettinen and Nurminen score method.

FINDINGS

56 436 individuals aged 5-17 years (20 227 aged 5-11 years and 36 209 aged 12-17 years) with EHRs in the Mayo Clinic Health Systems were included in the study. Overall, the reporting of adverse events remained low in passive surveillance. Serious adverse events were rare after the first and second doses of BNT162b2, with rates of anaphylaxis (six [0·01%] of 56 436), myocarditis (five [0·01%]), and pericarditis (three [0·01%]) consistent with previous studies. Among the 20 227 5-11-year-olds, there were increased risks of fatigue (58 after second dose vs 41 before first dose; risk difference [RD]_dose2 0·08% [95% CI -0·01 to 0·18], p=0·044) and fever (104 after second dose vs 77 before first dose; RD_dose2 0·13% [0·00 to 0·27], p=0·022) after the second dose. Among the 36 209 12-17-year-olds, there were increased risks of arthralgia (69 after second dose vs 48 before first dose; RD_dose2 0·06% [-0·00 to 0·12], p=0·026), chills (58 after second dose vs 40 before first dose; RD_dose2 0·05% [-0·00 to 0·11], p=0·034), and myalgia (96 after second dose vs 73 before first dose; RD_dose2 0·06% [-0·01 to 0·14], p=0·038) after the second dose. Although the overall incidence was low, there was an increased risk of myocarditis in males aged 12-17 years after the second dose (five after second dose vs zero before first dose; RD_dose2 0·03% [0·01 to 0·07], p=0·013), with median age being 15 years (IQR 14 to 16).

INTERPRETATION

Overall, this data suggests that vaccination with BNT162b2 in the paediatric population is generally safe and well-tolerated. Further research is warranted to investigate the basis for the increased risk of myocarditis in adolescent males. Additionally, further studies are needed to confirm whether the findings in our study population apply to the whole vaccinated paediatric population.

FUNDING

nference.

Pediatric Myocarditis

Myocarditis is a condition caused by acute or chronic inflammation of the cardiac myocytes, resulting in associated myocardial edema and myocardial injury or necrosis. The exact incidence is unknown, but is likely underestimated, with more mild cases going unreported. Diagnosis and appropriate management are paramount in pediatric myocarditis, as it remains a recognized cause of sudden cardiac death in children and athletes. Myocarditis in children is most often caused by a viral or infectious etiology. In addition, there are now two highly recognized etiologies related to Coronavirus disease of 2019 (COVID-19) infection and the COVID-19 mRNA vaccine. The clinic presentation of children with myocarditis can range from asymptomatic to critically ill. Related to severe acute respiratory syndrome-Coronavirus 2 (SARs-CoV-2), children are at greater risk of developing myocarditis secondary to COVID-19 compared to the mRNA COVID-19 vaccine. Diagnosis of myocarditis typically includes laboratory testing, electrocardiography (ECG), chest X-ray, and additional non-invasive imaging studies with echocardiogram typically being the first-line imaging modality. While the reference standard for diagnosing myocarditis was previously endomyocardial biopsy, with the new revised Lake Louise Criteria, cardiac magnetic resonance (CMR) has emerged as an integral non-invasive imaging tool to assist in the diagnosis. CMR remains critical, as it allows for assessment of ventricular function and tissue characterization, with newer techniques, such as myocardial strain, to help guide management both acutely and long term.

Severe Bacterial Infection Initially Misdiagnosed as MIS-C: Caution Needed

Working in the era of the novel coronavirus disease 2019 can predispose to cognitive bias. We present a case of life-threatening bacterial infection misdiagnosed as multisystem inflammatory syndrome in children. While multisystem inflammatory syndrome in children-related myocardial dysfunction is now a well-recognized complication of coronavirus disease 2019, a rigorous differential diagnosis approach, notably for infectious etiologies, is paramount.

A Systematic Review and Meta-analysis of the Association Between SARS-CoV-2 Vaccination and Myocarditis or Pericarditis

INTRODUCTION

There have been reports of potential negative cardiovascular effects from the COVID-19 vaccine, such as myocarditis or pericarditis. This study sought to ascertain the risk of myocarditis/pericarditis after COVID-19 vaccination by conducting an extensive meta-analysis of published cases.

METHODS

A systematic literature search was conducted in 7 online databases by March 31, 2022. Heterogeneity was tested by I² index. RR and 95% CI were pooled through either random-effect or fixed-effect models. Sensitivity analysis and publication bias were also conducted.

RESULTS

A total of 11 studies with 58,620,611 subjects were included. COVID-19 vaccination correlated with an increased risk of myocarditis or pericarditis (RR=2.04; 95% CI=1.33, 3.14). In addition, an increased risk of myocarditis or pericarditis in people who received the second dose of COVID-19 vaccine compared with that in those who received only the first dose of COVID-19 vaccine was also found (RR=4.06; 95% CI=2.08, 7.92). An increased incidence of pericarditis or myocarditis was noted predominantly in those who received BNT162b2 and mRNA-1273 vaccines (RR=2.19; 95% CI=1.46, 3.29 and RR=4.15; 95% CI=1.87, 9.22, respectively).

DISCUSSION

Study results indicate that a higher incidence of myocarditis or pericarditis was found after COVID-19 vaccination. In addition, the risk of developing myocarditis or pericarditis was greater after the second dose than after the first dose. Nevertheless, the risks of myocarditis and pericarditis in COVID-19 vaccine recipients are still significantly lower than the health risks observed in patients with COVID-19. Therefore, the benefits and harms must be carefully assessed to determine the best management option for patients who are in the high-risk group of myocarditis or pericarditis.

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.

Risk of Myocarditis After Sequential Doses of COVID-19 Vaccine and SARS-CoV-2 Infection by Age and Sex

BACKGROUND

Myocarditis is more common after severe acute respiratory syndrome coronavirus 2 infection than after COVID-19 vaccination, but the risks in younger people and after sequential vaccine doses are less certain.

METHODS

A self-controlled case series study of people ages 13 years or older vaccinated for COVID-19 in England between December 1, 2020, and December 15, 2021, evaluated the association between vaccination and myocarditis, stratified by age and sex. The incidence rate ratio and excess number of hospital admissions or deaths from myocarditis per million people were estimated for the 1 to 28 days after sequential doses of adenovirus (ChAdOx1) or mRNA-based (BNT162b2, mRNA-1273) vaccines, or after a positive SARS-CoV-2 test.

RESULTS

In 42 842 345 people receiving at least 1 dose of vaccine, 21 242 629 received 3 doses, and 5 934 153 had SARS-CoV-2 infection before or after vaccination. Myocarditis occurred in 2861 (0.007%) people, with 617 events 1 to 28 days after vaccination. Risk of myocarditis was increased in the 1 to 28 days after a first dose of ChAdOx1 (incidence rate ratio, 1.33 [95% CI, 1.09-1.62]) and a first, second, and booster dose of BNT162b2 (1.52 [95% CI, 1.24-1.85]; 1.57 [95% CI, 1.28-1.92], and 1.72 [95% CI, 1.33-2.22], respectively) but was lower than the risks after a positive SARS-CoV-2 test before or after vaccination (11.14 [95% CI, 8.64-14.36] and 5.97 [95% CI, 4.54-7.87], respectively). The risk of myocarditis was higher 1 to 28 days after a second dose of mRNA-1273 (11.76 [95% CI, 7.25-19.08]) and persisted after a booster dose (2.64 [95% CI, 1.25-5.58]). Associations were stronger in men younger than 40 years for all vaccines. In men younger than 40 years old, the number of excess myocarditis events per million people was higher after a second dose of mRNA-1273 than after a positive SARS-CoV-2 test (97 [95% CI, 91-99] versus 16 [95% CI, 12-18]). In women younger than 40 years, the number of excess events per million was similar after a second dose of mRNA-1273 and a positive test (7 [95% CI, 1-9] versus 8 [95% CI, 6-8]).

CONCLUSIONS

Overall, the risk of myocarditis is greater after SARS-CoV-2 infection than after COVID-19 vaccination and remains modest after sequential doses including a booster dose of BNT162b2 mRNA vaccine. However, the risk of myocarditis after vaccination is higher in younger men, particularly after a second dose of the mRNA-1273 vaccine.

Myocarditis or Pericarditis Following the COVID-19 Vaccination in Adolescents: A Systematic Review

Background: By 16 May 2022, 12,186,798,032 people had been vaccinated with COVID-19 vaccines. Our study found that myocarditis/pericarditis may occur in adolescents after COVID-19 vaccination. Methods: In this regard, we conducted a meta-analysis of seven groups of adolescents aged 12–19 years to compare the incidence of myocarditis/pericarditis after vaccination and compare the relative risk incidence after the first and second doses of a COVID-19 vaccine, and between males and females for risk incidence. Results: We analyzed 22,020,997 subjects from seven studies, including 130 cases of confirmed myocarditis/pericarditis. The overall mean incidence rate was 1.69 cases per 100,000 person-years. Of these, 19 of the 12,122,244 people who received a first dose of a COVID-19 vaccine had myocarditis/pericarditis, an incidence rate of 0.0022% (95% CI 0.0001–0.0034), and 111 of the 1,008,753 people who received a second dose had myocarditis/pericarditis, an incidence rate of 0.0107% (95% CI 0.0059–0.0155). The prevalence relative ratio (RR) after the first and second doses was RR = 5.53 (95% CI: 3.01–10.16), with a higher prevalence after the second dose than after the first dose of a COVID-19 vaccine. After a second dose of a COVID-19 vaccine, the RR for males relative to females was RR = 13.91 (95% CI: 4.30–44.95), with a more pronounced risk of disease in males than in females. Conclusions: Our study showed that myocarditis/pericarditis occurred after vaccination with the BNT162b2 or Comirnaty vaccine, especially after the second vaccination in male adolescents, but the incidence of myocarditis/pericarditis after vaccination with the above vaccines was very rare (0.0022%). Therefore, it is recommended that adolescents should be vaccinated with the COVID-19 universal vaccine as soon as possible and closely monitored for subsequent adverse reactions, which can be treated promptly.

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.

Myocarditis in Children: Impact of Early Presentation on Disease Outcomes at a Single Tertiary Center in Saudi Arabia

PURPOSE

Myocarditis is the inflammation of the heart muscle and can be caused by a variety of infections, incendiary diseases, and pollutants. It is challenging for an emergency pediatrician to have a sufficiently high degree of suspicion for myocarditis to avoid diagnostic delay given the broad overlap of myocarditis symptoms with other disease processes. The study aimed to evaluate the impact of early presentation and diagnosis on the outcomes of acute myocarditis in children.

PATIENTS AND METHODS

We performed a retrospective analysis of the complete records of 80 pediatric patients diagnosed with acute myocarditis between 2015 and 2019 at a single tertiary center in Saudi Arabia. Patients were two weeks to 14 years of age and were admitted to the pediatric intensive care unit (PICU) for various sequelae of myocarditis. Data from routine clinical and laboratory investigations were collected.

RESULTS

The incidence of delayed presentation at the hospital after the onset of symptoms of myocarditis was 42.5%. A total of 22 (27.5%) patients expired during their hospital stay. There was marginally significant association of earlier presentation with in-hospital survival (80.4% vs 61.8%) and delayed presentation with higher proportion of in-hospital mortality (38.2% vs 19.6%, p=0.064). The rate of mechanical ventilator was also marginally significant in delayed presentation (p=0.068). Shock and multisystem organ failure were the significantly associated manifestations of delayed acute myocarditis presentations. Length of stay in PICU was also significant in delayed presentation group. The impact of presenting symptoms, ECG findings, and use of mechanical ventilator was not significantly associated with delayed presentation.

CONCLUSION

An earlier presentation may have a substantial impact on overall prognosis and length of PICU stay and may lead to comparatively lesser frequency of mechanical ventilation use.

COVID-19 and Myocarditis: Review of Clinical Presentations, Pathogenesis and Management

There are four main myocarditis presentations identified in the context of severe acute respiratory coronavirus 2 (SARS-CoV-2): myocarditis associated with acute coronavirus disease 2019 (COVID-19) infection, post-acute COVID-19 syndrome, multisystem inflammatory syndrome, and vaccination-associated myocarditis. This article reviews the clinical features and current management strategies for each of these presentations. The overall prevalence of myocarditis is considered to be rare, although accurate estimation is affected by heterogeneity in diagnostic criteria and reporting, as well as infrequent use of gold-standard diagnostic endomyocardial biopsy. Severity of disease can range from mild symptoms to fulminant myocarditis. Therapeutic interventions are typically supportive and extrapolated from treatment for non-COVID-19 viral myocarditis. Several pathogenic mechanisms for the development of myocarditis have been proposed, and ongoing research is critical for elucidating disease pathogenesis and potentially identifying therapeutic targets. The long-term cardiovascular sequelae of SARS-CoV-2 infections and associated myocarditis require further elucidation and understanding.

SARS-CoV-2 Vaccination and Myocarditis in a Nordic Cohort Study of 23 Million Residents

Importance

Reports of myocarditis after SARS-CoV-2 messenger RNA (mRNA) vaccination have emerged.

Objective

To evaluate the risks of myocarditis and pericarditis following SARS-CoV-2 vaccination by vaccine product, vaccination dose number, sex, and age.

Design, Setting, and Participants

Four cohort studies were conducted according to a common protocol, and the results were combined using meta-analysis. Participants were 23 122 522 residents aged 12 years or older. They were followed up from December 27, 2020, until incident myocarditis or pericarditis, censoring, or study end (October 5, 2021). Data on SARS-CoV-2 vaccinations, hospital diagnoses of myocarditis or pericarditis, and covariates for the participants were obtained from linked nationwide health registers in Denmark, Finland, Norway, and Sweden.

Exposures

The 28-day risk periods after administration date of the first and second doses of a SARS-CoV-2 vaccine, including BNT162b2, mRNA-1273, and AZD1222 or combinations thereof. A homologous schedule was defined as receiving the same vaccine type for doses 1 and 2.

Main Outcomes and Measures

Incident outcome events were defined as the date of first inpatient hospital admission based on primary or secondary discharge diagnosis for myocarditis or pericarditis from December 27, 2020, onward. Secondary outcome was myocarditis or pericarditis combined from either inpatient or outpatient hospital care. Poisson regression yielded adjusted incidence rate ratios (IRRs) and excess rates with 95% CIs, comparing rates of myocarditis or pericarditis in the 28-day period following vaccination with rates among unvaccinated individuals.

Results

Among 23 122 522 Nordic residents (81% vaccinated by study end; 50.2% female), 1077 incident myocarditis events and 1149 incident pericarditis events were identified. Within the 28-day period, for males and females 12 years or older combined who received a homologous schedule, the second dose was associated with higher risk of myocarditis, with adjusted IRRs of 1.75 (95% CI, 1.43-2.14) for BNT162b2 and 6.57 (95% CI, 4.64-9.28) for mRNA-1273. Among males 16 to 24 years of age, adjusted IRRs were 5.31 (95% CI, 3.68-7.68) for a second dose of BNT162b2 and 13.83 (95% CI, 8.08-23.68) for a second dose of mRNA-1273, and numbers of excess events were 5.55 (95% CI, 3.70-7.39) events per 100 000 vaccinees after the second dose of BNT162b2 and 18.39 (9.05-27.72) events per 100 000 vaccinees after the second dose of mRNA-1273. Estimates for pericarditis were similar.

Conclusions and Relevance

Results of this large cohort study indicated that both first and second doses of mRNA vaccines were associated with increased risk of myocarditis and pericarditis. For individuals receiving 2 doses of the same vaccine, risk of myocarditis was highest among young males (aged 16-24 years) after the second dose. These findings are compatible with between 4 and 7 excess events in 28 days per 100 000 vaccinees after BNT162b2, and between 9 and 28 excess events per 100 000 vaccinees after mRNA-1273. This risk should be balanced against the benefits of protecting against severe COVID-19 disease.

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.

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.

Clinical Features of Patients Presenting to the Emergency Department With Cardiovascular Adverse Reactions After COVID-19 mRNA Vaccination

BACKGROUND

Since the implementation of the nationwide coronavirus disease 2019 (COVID-19) vaccination campaign, emergency departments (EDs) have had an increasing number of patients reporting postvaccination cardiovascular adverse effects. We investigated the clinical features of patients who visited the ED for cardiovascular adverse reactions after COVID-19 mRNA vaccination.

METHODS

We conducted a retrospective observational study in two EDs. Patients with cardiovascular adverse reactions after COVID-19 mRNA vaccination who visited EDs between June 1, 2021, and October 15, 2021, were selected. The clinical data of these patients were collected by reviewing medical records.

RESULTS

Among 683 patients, 426 (62.4%) were female. The number of patients in their 20s was the highest (38.9% of males, 28.2% of females) (P < 0.001). More patients visited the ED for adverse reactions following the first vaccine dose than following the second dose (67.6% vs. 32.2%). Chief complaints were chest pain/discomfort (74.4%), dyspnea (14.3%) and palpitation (11.3%). The final diagnosis was a nonspecific cause (63.1%), and 663 (97.1%) patients were discharged from the ED. The admission rate was higher in males than in females (3.9% vs. 1.9%). Myocarditis was diagnosed in four males, who showed mild clinical progression and were discharged within 5 hospital days.

CONCLUSION

Most patients who visited the ED with cardiovascular adverse reactions were discharged from the ED, but some were admitted for other medical diseases as well as adverse vaccine reactions. Therefore, further surveillance and a differential diagnosis of cardiovascular adverse events after COVID-19 mRNA vaccination should be considered by emergency physicians.

Myocarditis Cases Reported After mRNA-Based COVID-19 Vaccination in the US From December 2020 to August 2021

IMPORTANCE

Vaccination against COVID-19 provides clear public health benefits, but vaccination also carries potential risks. The risks and outcomes of myocarditis after COVID-19 vaccination are unclear.

OBJECTIVE

To describe reports of myocarditis and the reporting rates after mRNA-based COVID-19 vaccination in the US.

DESIGN, SETTING, AND PARTICIPANTS

Descriptive study of reports of myocarditis to the Vaccine Adverse Event Reporting System (VAERS) that occurred after mRNA-based COVID-19 vaccine administration between December 2020 and August 2021 in 192 405 448 individuals older than 12 years of age in the US; data were processed by VAERS as of September 30, 2021.

EXPOSURES

Vaccination with BNT162b2 (Pfizer-BioNTech) or mRNA-1273 (Moderna).

MAIN OUTCOMES AND MEASURES

Reports of myocarditis to VAERS were adjudicated and summarized for all age groups. Crude reporting rates were calculated across age and sex strata. Expected rates of myocarditis by age and sex were calculated using 2017-2019 claims data. For persons younger than 30 years of age, medical record reviews and clinician interviews were conducted to describe clinical presentation, diagnostic test results, treatment, and early outcomes.

RESULTS

Among 192 405 448 persons receiving a total of 354 100 845 mRNA-based COVID-19 vaccines during the study period, there were 1991 reports of myocarditis to VAERS and 1626 of these reports met the case definition of myocarditis. Of those with myocarditis, the median age was 21 years (IQR, 16-31 years) and the median time to symptom onset was 2 days (IQR, 1-3 days). Males comprised 82% of the myocarditis cases for whom sex was reported. The crude reporting rates for cases of myocarditis within 7 days after COVID-19 vaccination exceeded the expected rates of myocarditis across multiple age and sex strata. The rates of myocarditis were highest after the second vaccination dose in adolescent males aged 12 to 15 years (70.7 per million doses of the BNT162b2 vaccine), in adolescent males aged 16 to 17 years (105.9 per million doses of the BNT162b2 vaccine), and in young men aged 18 to 24 years (52.4 and 56.3 per million doses of the BNT162b2 vaccine and the mRNA-1273 vaccine, respectively). There were 826 cases of myocarditis among those younger than 30 years of age who had detailed clinical information available; of these cases, 792 of 809 (98%) had elevated troponin levels, 569 of 794 (72%) had abnormal electrocardiogram results, and 223 of 312 (72%) had abnormal cardiac magnetic resonance imaging results. Approximately 96% of persons (784/813) were hospitalized and 87% (577/661) of these had resolution of presenting symptoms by hospital discharge. The most common treatment was nonsteroidal anti-inflammatory drugs (589/676; 87%).

CONCLUSIONS AND RELEVANCE

Based on passive surveillance reporting in the US, the risk of myocarditis after receiving mRNA-based COVID-19 vaccines was increased across multiple age and sex strata and was highest after the second vaccination dose in adolescent males and young men. This risk should be considered in the context of the benefits of COVID-19 vaccination.

Population-based Incidence of Myopericarditis After COVID-19 Vaccination in Danish Adolescents

In this prospective nationwide multicenter study from Denmark, myopericarditis after Pfizer-BioNTech mRNA COVID-19 vaccination was identified in 13 males and 2 females between May 15 and September 15, 2021, among 133,477 vaccinated males and 127,857 vaccinated females 12-17 years of age, equaling 97 males and 16 females per million. In conclusion, the incidence of myopericarditis after COVID-19 vaccination among males appears higher than reports from the United States.

Myoglobin and left ventricular ejection fraction as predictive markers for death in children with fulminant myocarditis

BACKGROUND

Fulminant myocarditis (FM) is an inflammatory process of the myocardium and an important cause of cardiac dysfunction in children; it is characterized by rapid onset, acute progression, and high mortality. The study sought to describe the clinical characteristics and prognostic factors in children with FM.

METHODS

The study population consists of 37 consecutive patients admitted from May 2014 to December 2021 with a diagnosis of FM. According to the prognosis of children with FM during hospitalization, they were divided into "survival" group (25 cases) and "death" group (12 cases). A multivariate logistic regression analysis was performed to identify the independent predictors of in-hospital mortality in the patients, and receiver operating characteristic (ROC) curve was used to explore the predictive value of related factors.

RESULTS

The 37 children with FM had an average age of 8.35 ± 4.36 years old. Twenty-five of the patients survived and 12 died. Twenty-five of the children were discharged from the hospital after a series of active rescue treatments such as nutritional myocardial drugs, high-dose intravenous immunoglobulin (IVIG), glucocorticoids (GCs), temporary pacemaker (TP), extracorporeal membrane oxygenation (ECMO), and continuous renal replacement therapy (CRRT).Twelve of the children were classified into the death group because the resuscitation failed. The levels of procalcitonin (PCT), creatine kinase (CK), and myoglobin (MYO) in the death group were all higher than in the survival group (all P < 0.05), and the left ventricular ejection fraction (LVEF) in the death group was significantly lower than in the survival group (P = 0.002). The binary logistic regression analysis revealed that MYO [OR:1.006; 95%CI:(1-1.012); P = 0.045] and LVEF [OR: 0.876; 95% CI: (0.785-0.978); P = 0.019] were independent predictors of FM. ROC curve analysis showed that the area under ROC curve (AUC) of MYO and LVEF was [AUC:0.957; 95%CI:0.897~1] and [AUC:0.836; 95%CI:0.668~1], and the area under the combined ROC curve for MYO + LVEF was significantly higher than that for MYO or LVEF alone (P < 0.05), indicating that the MYO + LVEF combined diagnosis had a higher predictive value for FM.

CONCLUSION

The levels of MYO and LVEF can be markers for prognosis of FM and can effectively evaluate the disease severity. Their combination can improve forecast accuracy; thus, the detection of the above-mentioned indexes possesses a higher value for clinical applications.

Sex Differences in Incidence, Clinical Characteristics and Outcomes in Children and Young Adults Hospitalized for Clinically Suspected Myocarditis in the Last Ten Years-Data from the MYO-PL Nationwide Database

There is a widespread lack of systematic knowledge about myocarditis in children and young adults in European populations. The MYO-PL nationwide study aimed to evaluate sex differences in the incidence, clinical characteristics, management and outcomes of all young patients with a clinical diagnosis of myocarditis, hospitalized in the last ten years. The study involved data (from the only public healthcare insurer in Poland) of all (n = 3659) patients aged 0–20 years hospitalized for myocarditis in the years 2011–2019. We assessed clinical characteristics, management and five-year outcomes. Males comprised 75.4% of the study population. The standardized incidence rate of myocarditis increased over the last ten years and was, on average, 7.8 and 2.5 (in males and females, respectively). It was the highest (19.5) in males aged 16–20 years. The highest rates of hospital admissions occurred from late autumn to early spring. Most myocarditis-directed diagnostic procedures, including laboratory tests, echocardiography, coronary angiography, cardiac magnetic resonance and endomyocardial biopsy, were performed in a low number of patients, particularly in females. Most patients required rehospitalization for cardiovascular reasons. The results of this large epidemiological study showed an increasing incidence of myocarditis hospitalizations in young patients over last ten years and that it was sex-, age- and season-dependent. Survival in young patients with myocarditis was age- and sex-related and usually it was worse than in the national population. The general management of myocarditis requires significant improvement.

Occurrence, Trends, Management and Outcomes of Patients Hospitalized with Clinically Suspected Myocarditis-Ten-Year Perspectives from the MYO-PL Nationwide Database

The epidemiology of myocarditis is unknown and based mainly on small single-centre studies. The study aimed to evaluate the current incidence, clinical characteristics, management and outcomes of patients hospitalized due to myocarditis in a general population. The study was registered in ClinicalTrials.gov (NCT04827706). The nationwide MYO-PL (the occurrence, trends, management and outcomes of patients with myocarditis in Poland) database (years 2009–2020) was created to identify hospitalization records with a primary diagnosis of myocarditis according to the International Classification of Diseases and Related Health Problems, 10th Revision (ICD 10), derived from the database of the national healthcare insurer. We identified 19,978 patients who were hospitalized with suspected myocarditis for the first time, of whom 74% were male. The standardized incidence rate of myocarditis ranged from 1.15 to 14 per 100,000 people depending on the age group and was the highest in patients aged 16–20 years. The overall incidence increased with time. The performance of the recommended diagnostic tests (in particular, endomyocardial biopsy) was low. Relative five-year survival ranged from 0.99 to 0.56—worse in younger females and older males. During a five-year follow-up, 6% of patients (3.7% and 6.9% in females and males, respectively) were re-hospitalized for myocarditis. Surprisingly, females more frequently required hospitalization due to heart failure/cardiomyopathy (10.5%) and atrial fibrillation (5%) than compared to males (7.3% and 2.2%, respectively) in the five-year follow up. In the last ten years, the incidence of suspected myocarditis increased, particularly in males. Survival rates for patients with myocarditis were worse than in the general population. Management of myocarditis requires significant improvement.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Symptomatic Acute Myocarditis in 7 Adolescents After Pfizer-BioNTech COVID-19 Vaccination

Trials of coronavirus disease 2019 (COVID-19) vaccination included limited numbers of children, so they may not have detected rare but important adverse events in this population. We report 7 cases of acute myocarditis or myopericarditis in healthy male adolescents who presented with chest pain all within 4 days after the second dose of Pfizer-BioNTech COVID-19 vaccination. Five patients had fever around the time of presentation. Acute COVID-19 was ruled out in all 7 cases on the basis of negative severe acute respiratory syndrome coronavirus 2 real-time reverse transcription polymerase chain reaction test results of specimens obtained by using nasopharyngeal swabs. None of the patients met criteria for multisystem inflammatory syndrome in children. Six of the 7 patients had negative severe acute respiratory syndrome coronavirus 2 nucleocapsid antibody assay results, suggesting no previous infection. All patients had an elevated troponin. Cardiac MRI revealed late gadolinium enhancement characteristic of myocarditis. All 7 patients resolved their symptoms rapidly. Three patients were treated with nonsteroidal antiinflammatory drugs only, and 4 received intravenous immunoglobulin and corticosteroids. In this report, we provide a summary of each adolescent's clinical course and evaluation. No causal relationship between vaccine administration and myocarditis has been established. Continued monitoring and reporting to the US Food and Drug Administration Vaccine Adverse Event Reporting System is strongly recommended.

Epidemiology and Clinical Features of Myocarditis/Pericarditis before the Introduction of mRNA COVID-19 Vaccine in Korean Children: a Multicenter Study

BACKGROUND

Korean health authority plans to vaccinate adolescents against coronavirus disease 2019 (COVID-19) starting high school seniors during the summer vacation of 2021. However, the myocarditis/pericarditis following COVID-19 vaccine has been reported recently in adolescents and young adults. This study was performed to answer the urgent questions about the basic epidemiology and clinical course of myocarditis/pericarditis in hospitalized patients prior to the introduction of COVID-19 vaccines in pediatric population.

METHODS

A retrospective medical record analysis including frequency, clinical characteristics, etiology and outcome of myocarditis/pericarditis was conducted in 17 years and younger patients who were hospitalized in two referral hospitals in Korea between 2010 and 2019.

RESULTS

Total 142 patients with myocarditis (n = 119) and/or pericarditis (n = 23) were identified. Median age was 5.4 years (interquartile range, 0.6-12.9 years; range, 11 days-17.8 years), and male was 61%. In adolescents aged 12-17 years, the male to female ratio was 3.2. Myocarditis/pericarditis occurred 0.70 per 1,000 in-patients during the study period: 0.96 (< 1 year), 0.50 (1-5 years), 0.67 (6-11 years) and 1.22 (12-17 years) per 1,000 in-patients, respectively. There was an increasing tendency for the annual frequency from 0.34 in 2010 to 1.25 per 1,000 in-patients in 2019 (P = 0.021). Among the 56 (40%) proven pathogens at admission, Mycoplasma pneumoniae (n = 11, 8%) and enterovirus (n = 10, 7%) were most common. Of the 142 patients, 99 (70%) required pediatric intensive care unit care and 10 (7%) received heart transplantation. In addition, 61 patients (61/131, 47%) without heart medication at admission needed heart medication when they were discharged. Eleven (7.7%) patients died, of which five patients were previously healthy. The median age of deceased patients was lower than the survival group (0.8 vs. 6.3 years, P = 0.014).

CONCLUSION

The frequency of myocarditis/pericarditis was highest among male adolescent in-patients; however, the outcome was favorable in this group without any mortality.

Update on acute myocarditis

Acute myocarditis (AM), a recent-onset inflammation of the heart, has heterogeneous clinical presentations, varying from minor symptoms to high-risk cardiac conditions with severe heart failure, refractory arrhythmias, and cardiogenic shock. AM is moving from being a definitive diagnosis based on histological evidence of inflammatory infiltrates on cardiac tissue to a working diagnosis supported by high sensitivity troponin increase in association with specific cardiac magnetic resonance imaging (CMRI) findings. Though experts still diverge between those advocating for histological definition versus those supporting a mainly clinical definition of myocarditis, in the real-world practice the diagnosis of AM has undoubtedly shifted from being mainly biopsy-based to solely CMRI-based in most of clinical scenarios. It is thus important to clearly define selected settings where EMB is a must, as information derived from histology is essential for an optimal management. As in other medical conditions, a risk-based approach should be promoted in order to identify the most severe AM cases requiring appropriate bundles of care, including early recognition, transfer to tertiary centers, aggressive circulatory supports with inotropes and mechanical devices, histologic confirmation and eventual immunosuppressive therapy. Despite improvements in recognition and treatment of AM, including a broader use of promising mechanical circulatory supports, severe forms of AM are still burdened by dismal outcomes. This review is focused on recent clinical studies and registries that shed new insights on AM. Attention will be paid to contemporary outcomes and predictors of prognosis, the emerging entity of immune checkpoint inhibitors-associated myocarditis, updated CMRI diagnostic criteria, new data on the use of temporary mechanical circulatory supports in fulminant myocarditis. The role of viruses as etiologic agents will be reviewed and a brief update on pediatric AM is also provided. Finally, we summarize a risk-based approach to AM, based on available evidence and clinical experience.

Global, Regional, and National Burden of Myocarditis From 1990 to 2017: A Systematic Analysis Based on the Global Burden of Disease Study 2017

Objective: The global trends in myocarditis burden over the past two decades remain poorly understood and might be increasing during the coronavirus disease 2019 (COVID-19) worldwide pandemic. This study aimed to provide comprehensive estimates of the incidence, mortality, and disability-adjusted life years (DALYs) for myocarditis globally from 1990 to 2017.

Methods: Data regarding the incidence, mortality, DALY, and estimated annual percentage change (EAPC) between 1990 and 2017 for myocarditis worldwide were collected and calculated from the 2017 Global Burden of Disease study. We additionally calculated the myocarditis burden distribution based on the Socio-Demographic Index (SDI) quintile and Human Development Index (HDI).

Results: The incidence cases of myocarditis in 2017 was 3,071,000, with a 59.6% increase from 1990, while the age-standardized incidence rate (ASIR) was slightly decreased. The number of deaths due to myocarditis increased gradually from 27,120 in 1990 to 46,490 in 2017. The middle SDI quintile showed the highest number of myocarditis-related deaths. On the contrary, the global age-standardized death rate (ASDR) decreased with an overall EAPC of −1.4 [95% uncertainty interval (UI) = −1.8 to −1.0]. Similar to ASDR, the global age-standardized DALY rate also declined, with an EAPC of −1.50 (95% UI = −2.30 to −0.8) from 1990 to 2017. However, there was a 12.1% increase in the number of DALYs in the past 28 years; the middle SDI and low-middle SDI quintiles contributed the most to the DALY number in 2017. We also observed significant positive correlations between the EPAC of age-standardized rate and HDI for both death and DALY in 2017.

Conclusions: Globally, the ASIR, ASDR, and age-standardized DALY rate of myocarditis decreased slightly from 1990 to 2017. The middle SDI quintile had the highest level of ASIR, ASDR, and age-standardized DALY rate, indicating that targeted control should be developed to reduce the myocarditis burden especially based on the regional socioeconomic status. Our findings also provide a platform for further investigation into the myocarditis burden in the era of COVID-19.

Pediatric Fulminant Myocarditis in Japan: A Retrospective Nationwide Database Study of Hospital Volume, Management Practices, and Mortality

OBJECTIVES

Pediatric fulminant myocarditis is a subset of pediatric acute myocarditis associated with critical illness. We aimed to compare mortality and other outcomes such as length of hospital stay between pediatric fulminant myocarditis and nonfulminant myocarditis. For the subgroup of patients with fulminant myocarditis, we also aimed to describe the current management practices and evaluate the impact of clinically relevant factors, including hospital case volume, on mortality.

DESIGN

Retrospective observational study using the Diagnosis Procedure Combination database from April 2012 to March 2018.

SETTING

Over 1,000 acute care hospitals in Japan.

PATIENTS

Patients with acute myocarditis less than 18 years old, including patients with fulminant myocarditis (i.e., those who received at least one of the following by day 7 of hospitalization: inotropes/vasopressors, mechanical circulatory support, or cardiopulmonary resuscitation).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Multivariable logistic regression analysis was conducted to investigate the association between clinically relevant factors and in-hospital mortality of patients with fulminant myocarditis. Furthermore, post hoc propensity score analyses (propensity score-adjusted, propensity score-matched, and inverse probability of treatment-weighted analyses) were performed to confirm the effect of hospital case volume on in-hospital mortality. In total, 866 pediatric patients with acute myocarditis were included, and 382 (44.1%) were categorized as fulminant myocarditis. In-hospital mortality for those with fulminant myocarditis was 24.1%. fulminant myocarditis was associated with 41.3-fold greater odds of mortality than nonfulminant myocarditis (95% CI, 14.7-115.9; p < 0.001). In the subgroup of patients with fulminant myocarditis, a higher in-hospital mortality was significantly associated with younger age (≤ 5 yr; odds ratio, 3.41; 95% CI, 1.75-6.64) and the need for either mechanical ventilation (odds ratio, 2.39; 95% CI, 1.03-5.57), cardiopulmonary resuscitation (odds ratio, 10.63; 95% CI, 5.52-20.49), or renal replacement therapy (odds ratio, 2.53; 95% CI, 1.09-5.87) by day 7. A lower in-hospital mortality rate was significantly associated with treatment at hospitals in the highest pediatric fulminant myocarditis case volume tertile (≥ 6 cases in 6 yr; odds ratio, 0.30; 95% CI, 0.13-0.68) compared with treatment at hospitals in the lowest tertile (1-2 cases in 6 yr). Post hoc propensity score analyses consistently supported the primary results.

CONCLUSIONS

In-hospital mortality of pediatric fulminant myocarditis in Japan remains high. Treatment at hospitals in the highest pediatric fulminant myocarditis case volume tertile (≥ 6 cases in 6 yr) was associated with a 70% relative reduction in odds of in-hospital mortality compared with treatment at hospitals in the lowest tertile (1-2 cases in 6 yr). The reasons for such differences need further study.

Trends in Acute Myocarditis Related Pediatric Hospitalizations in the United States, 2007-2016

There has been little exploration of acute myocarditis trends in children despite notable advancements in care over the past decade. We explored trends in pediatric hospitalizations for acute myocarditis from 2007 to 2016 in the United States (US). This was a retrospective, serial cross-sectional study of the National Inpatient Sample database from 2007 to 2016, identifying patients ≤18 years hospitalized with acute myocarditis. Patient demographics and incidence trends were examined. Other relevant clinical and resource utilization outcomes were also explored. Out of 60,390,000 weighted pediatric hospitalizations, 6371 were related to myocarditis. The incidence of myocarditis increased from 0.7 to 0.9 per 100,000 children (p <0.0001) over the study period. The mortality decreased from 7.5% to 6.1% (p = 0.02). A significant inflation-adjusted increase by $4,574 in the median hospitalization cost was noted (p = 0.02) while length of stay remained stable (median 6.1 days). Tachyarrhythmias were identified as the most common type of associated arrhythmia. The occurrence of congestive heart failure remained steady at 27%. In conclusion, in-hospital mortality associated with pediatric acute myocarditis has decreased in the United States over years 2007 to 2016 with a concurrent rise in incidence. Despite steady length of stay, hospitalization costs have increased. Future studies investigating long-term outcomes relating to acute myocarditis are warranted.

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

BACKGROUND

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

OBJECTIVE

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

DISCUSSION

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

CONCLUSION

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