Clinical characteristics and long-term outcome of acute myocarditis in children

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.

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.

Q wave in paediatric myocarditis: an underinvestigated, readily available prognostic factor

BACKGROUND

Myocarditis is an uncommon disease in children with potentially fatal consequences. An electrocardiogram (ECG) change seen in myocarditis is pathological Q wave. Pathological Q wave is linked to permanent damage and myocardial death in several cardiac diseases. We investigated the significance of pathological Q waves in children with acute myocarditis (AM).

METHODS

This retrospective observational study analysed the data of 59 children with AM admitted to our hospital between January 2016 and July 2021. They were divided into Q wave and non-Q wave myocarditis groups. Patients' laboratory data, echocardiography, treatment and hospital outcome were analysed.

RESULTS

Patients were 64.4% male and had a median age of 6 years and 9 months. Pathological Q waves were found in 52.5% of the patients. Q wave myocarditis group had higher troponin I values (499 vs. 145 ng/L, p = 0.011) and longer hospital stays (13 vs. 9 days, p = 0.020) than the non-Q wave group. They also required higher doses of inotropic or vasoactive drugs. 61.3% of Q wave patients needed mechanical ventilation compared to 35.7% of non-Q wave patients (p = 0.069). All the patients who died or discharged with an LVEF < 30% belonged to the Q wave group.

CONCLUSION

Q wave in AM warrants close monitoring and intensive treatment as it accompanies more severe complications and poorer outcomes. This readily available ECG finding can be a clue to prognoses of AM patients. Further research with larger populations is needed to better understand Q wave prognostic accuracy and its potential role in guiding more expensive treatments.

Soluble suppression of tumorigenicity 2 associated with fulminant myocarditis in children: A retrospective observational study

Fulminant myocarditis (FM) is associated with high mortality, and studies on soluble suppression of tumorigenicity 2 (sST2) and myocarditis are still scarce. The aim of this study was to investigate the relationship between sST2 and FM in children with myocarditis. This was a single-center retrospective clinical observational study. We continuously included patients diagnosed as suspected viral myocarditis from December 2019 to December 2022. A total of 203 patients younger than 11 years old were enrolled in this study, 22 of whom were diagnosed with FM. The level of sST2 was positively correlated with N-terminal B-type natriuretic peptide (NT-proBNP) (R = 0.5588, P < .0001). After including multiple factors, creatinine (odd ratio [OR] 0.911; 95% confidence interval [CI], 0.842-0.986; P = .021), NT-proBNP (OR 1.000; 95% CI, 1.000-1.000; P = .01), left ventricular ejection fraction (OR 1.306; 95% CI, 1.153-1.478; P < .001) and sST2 (OR 0.982; 95% CI, 0.965-0.999; P = .038) were still risk factors for FM. The area under curve values were 0.852 for the NT-proBNP, 0.817 for the creatinine, 0.914 for the left ventricular ejection fraction, and 0.865 for the sST2, which showed good sensitivity and specificity for FM. Elevated level of sST2 was associated with fulminant myocarditis. sST2 might be used as a potential biomarker for the diagnosis of fulminant myocarditis.

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.

Clinical characteristics and mortality risk prediction model in children with acute myocarditis

BACKGROUND

Acute myocarditis (AMC) can cause poor outcomes or even death in children. We aimed to identify AMC risk factors and create a mortality prediction model for AMC in children at hospital admission.

METHODS

This was a single-center retrospective cohort study of AMC children hospitalized between January 2016 and January 2020. The demographics, clinical examinations, types of AMC, and laboratory results were collected at hospital admission. In-hospital survival or death was documented. Clinical characteristics associated with death were evaluated.

RESULTS

Among 67 children, 51 survived, and 16 died. The most common symptom was digestive disorder (67.2%). Based on the Bayesian model averaging and Hosmer-Lemeshow test, we created a final best mortality prediction model (acute myocarditis death risk score, AMCDRS) that included ten variables (male sex, fever, congestive heart failure, left-ventricular ejection fraction < 50%, pulmonary edema, ventricular tachycardia, lactic acid value > 4, fulminant myocarditis, abnormal creatine kinase-MB, and hypotension). Despite differences in the characteristics of the validation cohort, the model discrimination was only marginally lower, with an AUC of 0.781 (95% confidence interval = 0.675-0.852) compared with the derivation cohort. Model calibration likewise indicated acceptable fit (Hosmer‒Lemeshow goodness-of-fit, P¼ = 0.10).

CONCLUSIONS

Multiple factors were associated with increased mortality in children with AMC. The prediction model AMCDRS might be used at hospital admission to accurately identify AMC in children who are at an increased risk of death.

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.

Cardiac Biomarkers in Pediatrics: An Undervalued Resource

BACKGROUND

The clinical use of common cardiac biomarkers, such as brain natriuretic peptides and troponins, has traditionally been limited to adult populations in the assessment of heart failure and acute coronary syndrome, respectively. While many have discounted the value of these markers in pediatric populations, emerging evidence suggests they may be useful in the diagnosis and prognostication of many cardiac and noncardiac pathologies in neonates, children, and adolescents, and an increasing number of pediatric hospitals are routinely measuring cardiac markers in their clinical practice.

CONTENT

This review summarizes and critically evaluates the current literature regarding the application of cardiac biomarkers for clinical decision-making in the pediatric population. Main potential clinical indications discussed herein include primary cardiac disease, immune-related conditions, and noncardiac disease. Important diagnostic and interpretative challenges are also described in relation to each potential indication.

SUMMARY

Despite a general lack of clinical awareness regarding the value of cardiac biomarkers in pediatrics, there is increasing literature to support their application in various contexts. Cardiac biomarkers should be considered an undervalued resource in the pediatric population with potential value in the diagnosis and prognosis of myocarditis, congenital heart disease, and heart failure, as well as in the assessment of severity and cardiac involvement in immune-related and other systemic conditions. While interpretation remains challenging in pediatrics due to the age- and sex-specific dynamics occurring throughout growth and development, this should not prevent their application. Future research should focus on defining evidence-based cut-offs for specific indications using the most up-to-date assays.

Extracorporeal Membrane Oxygenation for Fulminant Myocarditis: Increase of Cardiac Enzyme and SOFA Score Is Associated with High Mortality

We aimed to evaluate the outcomes of patients with fulminant myocarditis and investigate the factors associated with mortality. This is a retrospective single-center cohort study that included adult and pediatric patients with fulminant myocarditis treated at Samsung Medical Center between September 2004 and December 2019. The primary outcome was in-hospital mortality. Among 100 patients, 71 underwent veno-arterial extracorporeal membrane oxygenation (ECMO) (ECMO group). Comorbidities were not significantly different between the ECMO and non-ECMO groups. Cardiac enzymes, creatinine, and median sequential organ failure assessment (SOFA) score at intensive care unit admission were significantly different between the groups. Twenty patients (28.7%) in the ECMO group and two (6.9%) in the non-ECMO group died in-hospital (p = 0.02). The significant risk factors of in-hospital mortality were creatine kinase MB fraction (CK-MB) and SOFA score (p = 0.009 and p = 0.001, respectively) in the ECMO group. In the receiver-operating characteristic curve analysis, the cutoffs of SOFA score and CK-MB were 12 and 94.74 ng/mL, respectively. The patients with both variables above the cutoffs showed significantly worse outcomes (p < 0.001). ECMO can be an effective treatment option for fulminant myocarditis. SOFA score and CK-MB are significant risk factors for in-hospital mortality.

Impact of ventricular arrhythmias on outcomes in children with myocarditis

Children affected with acute myocarditis may progress rapidly into profound ventricular dysfunction and ventricular arrhythmias. The objective of this study is to assess the impact of ventricular arrhythmias on in-hospital mortality and the use of mechanical circulatory support in patients with myocarditis. Pediatric patients (age 0-18 years) admitted with myocarditis were identified from the National Inpatient Sample dataset for the years 2002-2015. A total of 12,489 patients with myocarditis were identified. Of them, 1627 patients were with ventricular arrhythmias and 10,862 patients without ventricular arrhythmias. Mortality was higher in those with ventricular arrhythmias (19.5% vs. 2.8%, OR = 8.47; 95% CI 7.16-10.04; p < 0.001). The median length of stay and the median cost of hospitalization were higher in the ventricular arrhythmias group (9 days vs. 4 days, p < 0.001 and $121,826 vs. $37,658, p < 0.001, respectively). There was a substantial increase in the utilization of extracorporeal membrane oxygenation (ECMO) in patients with ventricular arrhythmias (25.4% vs. 2.7%, OR = 12.40; 95% CI 10.55-14.57; p < 0.001). The use of ventricular assist devices (VADs) was higher in patients with ventricular arrhythmias (4.5% vs. 1.3%, OR = 3.76; 95% CI 2.82-5.01; p < 0.001). An improvement in discharge survival was observed over the years of study in both VA and non-VA groups; associated with this decline in mortality, there was a rising trend of ECMO utilization.Conclusion: Development of ventricular arrhythmia in children with myocarditis is a strong predictor for mortality and ECMO utilization. What is Known: • The clinical presentation of pediatric myocarditis varies from no symptoms of myocardial dysfunction to a rapidly progressing severe congestive heart failure. • Little is known about the predictors of mortality in children with suspected myocarditis. What is New: • Development of ventricular arrhythmia in children with myocarditis is a strong predictor for mortality and ECMO utilization. • Improvement in discharge survival was observed over the years of study; associated with this decline in mortality, there was a rising trend of ECMO utilization.

Diagnosis, Evaluation, and Treatment of Myocarditis in Children

Myocarditis in the pediatric population can be a challenging diagnosis to make and often requires utilization of multiple diagnostic modalities. The cause is often due to a viral infection with activation of the innate and acquired immune response with either recovery or disease progression. Laboratory testing often includes inflammatory markers, cardiac troponin levels, and natriuretic peptides. Noninvasive testing should include electrocardiogram, echocardiogram, and possibly an MRI. Treatment of myocarditis remains controversial with most providers using immune modulators with intravenous immunoglobulin and corticosteroids.

QRS fragmentation in children with suspected myocarditis: a possible additional diagnostic sign

AIMS

We aim to assess the diagnostic role of QRS fragmentation in children with suspected acute myocarditis.

BACKGROUND

Diagnosis of myocarditis in the paediatric population is challenging. Clinical suspicion, electrocardiogram, and laboratory tests are the main diagnostic features at presentation. However, electrocardiogram in patients with myocarditis is usually considered aspecific. We have previously described QRS fragmentation in adult patients with acute myocarditis.

METHODS

Patients aged less than 18 years, admitted between 2003 and 2019, and discharged with a diagnosis of acute myocarditis were included. Standard electrocardiogram, laboratory, and echocardiographic findings at admission and follow-up were reviewed. QRS fragmentation was defined by the presence of multiphasic R' spikes. Cardiac magnetic resonance and biopsy were performed in selected patients.

RESULTS

Twenty-one patients were analysed, 16 males (76%), median age 9.5 (2.5-16) years. At presentation, 12 patients (57%) displayed QRS fragmentation. Median ejection fraction was 40% (27-60). Nine patients (43%) underwent cardiac magnetic resonance and displayed late gadolinium enhancement. One patient underwent biopsy that showed borderline findings. Electrocardiogram leads showing QRS fragmentation correlated with distribution of late gadolinium enhancement. Median follow-up was 600 (190-2343) days. All patients were alive at last follow-up. Six patients (33%) patients displayed persistence of QRS fragmentation. Median ejection fraction was 60% (60-65%). In three patients (14%), ejection fraction remained depressed, two of which showed persistence of QRS fragmentation.

CONCLUSION

In this cohort of children with suspected myocarditis, QRS fragmentation was confirmed as a new additional diagnostic finding to look for at admission and during follow-up.

Inflammation in myocardial disease: From myocarditis to dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is a heterogeneous group of myocardial diseases clinically defined by the presence of left ventricular dilatation and contractile dysfunction. Among various causes of DCM, a progression from viral myocarditis to DCM has long been hypothesized. Supporting this possibility, studies by endomyocardial biopsy, the only method to obtain a definite diagnosis of myocarditis at present, have provided evidence of inflammation in the myocardium in DCM patients. A number of experimental studies have elucidated a cell-mediated autoimmune mechanism triggered by viral infection in the progression of myocarditis to DCM. In addition, the important role of inflammation in the pathogenesis of heart failure has been recognized, and many terms including myocarditis, inflammatory cardiomyopathy, and inflammatory DCM have been used for myocardial diseases associated with inflammation. This review discusses the pathophysiology of inflammation in the myocardium, and refers to diagnosis and treatment based on these concepts.

Pediatric Acute Myocarditis: Predicting Hemodynamic Compromise at Presentation to Health Care

BACKGROUND

The clinical spectrum of pediatric acute myocarditis ranges from minimal symptoms with intact hemodynamics to rapid cardiovascular collapse and death. We sought to identify factors on initial presentation associated with subsequent hemodynamic compromise.

METHODS

We performed a retrospective cohort study of patients with acute myocarditis at a freestanding pediatric hospital from 2007 to 2016. We defined 2 cohorts: high-acuity patients with hemodynamic compromise defined as requiring inotropic or vasoactive medications, cardiopulmonary resuscitation, extracorporeal membrane oxygenation, ventricular assist devices, or transplant or who died and low-acuity patients without these interventions. We collected the first recorded set of vital signs, symptoms, laboratory values, and chest radiograph, electrocardiogram, and echocardiography results. Univariate analysis was performed, and 2 multivariable logistic regression models were created to discriminate between cohorts.

RESULTS

A total of 74 patients were included: 33 high acuity and 41 low acuity. There were significant differences in demographics, symptoms, and physical examination, laboratory, electrocardiogram, and echocardiography findings between high- and low-acuity cohorts. Multivariable logistic regression models were highly discriminate in predicting those in the high-acuity cohort. The first model included presence of tachycardia, tachypnea, creatinine, and cardiomegaly on chest radiograph (area under the curve = 0.913). The second model added the presence of pericardial effusion to the above variables (area under the curve = 0.964).

CONCLUSIONS

Models based on factors available at initial presentation with acute myocarditis are predictive of subsequent hemodynamic compromise. If our results can be validated in a multicenter study, these models may help disposition patients with suspected acute myocarditis (with those who meet model criteria being admitted to centers capable of rapidly providing extracorporeal membrane oxygenation, ventricular assist devices, and heart transplant evaluation).

Cellular fraction analysis of pericardial effusion helps the diagnosis of eosinophilic myocarditis

Eosinophilic myocarditis is rare in children, and consequently, it is difficult to diagnose eosinophilic myocarditis rapidly. We report the clinical course of acute eosinophilic myocarditis with pericarditis in two adolescent boys and their associated electrocardiograms. The two patients, 13- and 14-year-old boys, developed cardiomegaly and chest pain with vomiting. On examination by two-dimensional echocardiography, thickening of the ventricular septum and a pericardial effusion were detected. The eosinophil count had increased by the pericardial effusion. Acute eosinophilic myocarditis often complicates a moderate to severe pericardial effusion owing to acute pericarditis. A cellular fraction analysis of the pericardial effusion is easy and useful for the diagnosis of eosinophilic myocarditis. Some serial changes in the electrocardiogram occur during each stage of acute eosinophilic myocarditis. They are induced by eosinophilic granules, which are capable of inducing tissue damage and dysfunction, and those changes in the electrocardiogram resemble the changes after an acute myocardial infarction. It is important to know the characteristics of eosinophilic myocarditis in order to prevent lethal complications.

Myocarditis Elicits Dendritic Cell and Monocyte Infiltration in the Heart and Self-Antigen Presentation by Conventional Type 2 Dendritic Cells

Autoimmune myocarditis often leads to dilated cardiomyopathy (DCM). Although T cell reactivity to cardiac self-antigen is common in the disease, it is unknown which antigen presenting cell (APC) triggers autoimmunity. Experimental autoimmune myocarditis (EAM) was induced by immunizing mice with α-myosin loaded bone marrow APCs cultured in GM-CSF. APCs found in such cultures include conventional type 2 CD11b⁺ cDCs (GM-cDC2s) and monocyte-derived cells (GM-MCs). However, only α-myosin loaded GM-cDC2s could induce EAM. We also studied antigen presenting capacity of endogenous type 1 CD24⁺ cDCs (cDC1s), cDC2s, and MCs for α-myosin-specific TCR-transgenic TCR-M CD4⁺ T cells. After EAM induction, all cardiac APCs significantly increased and cDCs migrated to the heart-draining mediastinal lymph node (LN). Primarily cDC2s presented α-myosin to TCR-M cells and induced Th1/Th17 differentiation. Loss of IRF4 in Irf4^fl/fl.Cd11cCre mice reduced MHCII expression on GM-cDC2s in vitro and cDC2 migration in vivo. However, partly defective cDC2 functions in Irf4^fl/fl.Cd11cCre mice did not suppress EAM. MCs were the largest APC subset in the inflamed heart and produced pro-inflammatory cytokines. Targeting APC populations could be exploited in the design of new therapies for cardiac autoimmunity.

Heart macrophages and dendritic cells in sickness and in health: A tale of a complicated marriage

Heart disease is the major cause of death and it is broadly recognized that the immune system plays a central role in healthy and injured heart. Here, we focus on the contribution of various subsets of mononuclear phagocytes in the cardiac system. Macrophages and dendritic cells reside in the healthy myocardium to fulfill homeostatic functions and rapidly increase in numbers in diseases like myocardial ischemia and myocarditis to contribute to disease or resolve it. Recent experiments have revealed the extraordinary heterogeneity of cardiac mononuclear phagocytes that differ in origin, lifespan, phenotype and function. Although many studies described cardiac phagocytes in the mouse, subsets of cardiac mononuclear phagocytes can also be broadly found in the human heart, opening up the potential of selective targeting of these cells in a therapeutic setting. Before this goal can be achieved we need better understanding not only of the detrimental but also beneficial functions of these highly diverse cells in the heart.

Contemporary Postnatal Incidence of Acquiring Acute Myocarditis by Age 15 Years and the Outcomes From a Nationwide Birth Cohort

OBJECTIVES

Acute myocarditis can be lethal, but the incidence remains unclear because of its wide manifestation spectrum. We investigated the postnatal incidence of acute myocarditis and risk factors for morbidity and mortality.

DESIGN

Retrospective derived birth cohort study.

SETTING

Taiwan National Health Insurance Database for the period 2000-2014.

PATIENTS

Children born between 2000 and 2009 with complete postnatal medical care data for at least 5 years.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

From among 2,150,590 live births, we identified 965 patients (54.8% male) admitted with the diagnosis of acute myocarditis, accounting for an overall incidence of 0.45/1,000. The cumulative incidence rates were 0.19/1,000, 0.38/1,000, 0.42/1,000, and 0.48/1,000 by ages 1, 5, 10, and 15 years, respectively. Male predominance was noted in infants and school age children (age group 6-14 yr). Arrhythmias, including tachyarrhythmia (4.8%) and bradyarrhythmia (1.1%), occurred in 56 patients. Extracorporeal membrane oxygenation support was provided to 62 patients (6.4%) and additional left ventricular assist devices in six of them. The mortality at discharge was 6.3%. The presence of ventricular tachyarrhythmia, bradyarrhythmia, and an onset at school age (6-14 yr) were associated with increased odds for the need for extracorporeal membrane oxygenation, which was the only predictor for mortality at discharge (hazard ratio, 7.85; 95% CI, 3.74-9.29). In patients who survived the acute myocarditis, late mortality was relatively low (36/904 = 4.0%). The overall survival of children with acute myocarditis were 90.9%, 90.3%, and 89.8% by the intervals of 1, 5, and 10 years after the myocarditis, respectively.

CONCLUSIONS

This birth cohort study determined the cumulative incidence of acute myocarditis for neonates by 15 years old to be one in 2,105. In an era of extracorporeal membrane oxygenation, the need of extracorporeal membrane oxygenation may reflect the severity of acute myocarditis and predict its outcome.

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

Background

Epidemiology of myocarditis in childhood is largely unknown. Men are known to have a higher incidence of myocarditis than women in adults aged <50 years, but whether this is true by sex in pediatric age groups is unknown. We set out to study the occurrence and potential sex differences of myocarditis in a general pediatric population.

Methods and Results

Data of all hospital admissions with myocarditis in Finland occurring in patients aged ≤15 years from 2004 to 2014 were collected from a mandatory nationwide registry. All patients with myocarditis as a primary, secondary, or tertiary cause of admission were included. Total and age‐ and sex‐specific incidence rates were calculated using corresponding population data. There were 213 admissions with myocarditis in pediatric patients. Myocarditis was the primary cause of admission in 86%. The overall incidence rate of myocarditis was 1.95/100 000 person‐years. Of all patients, 77% were boys, but sex differences in incidence rates were age‐dependent. In children aged 0 to 5 years, there was no sex difference in the occurrence of myocarditis. Boys aged 6 to 10 years had a higher incidence rate compared with girls (72% boys; incidence rate ratio: 2.46; 95% confidence interval, 1.03–5.89; P=0.04). Sex difference further increased in children aged 11 to 15 years (80% boys; incidence rate ratio: 3.5; 95% confidence interval, 2.68–5.67; P<0.0001).

Conclusions

Myocarditis leading to hospital admission is relatively uncommon in children, but occurrence of myocarditis increases with age. There is no sex difference in the risk of myocarditis during the first 6 years of life, but boys have a significantly higher risk at ages 6 to 15 years.

Predictors of Extracorporeal Membrane Oxygenation Support for Children with Acute Myocarditis

The clinical presentation of acute myocarditis in children may range from asymptomatic to sudden cardiac arrest. This study analyzed the clinical spectrum of acute myocarditis in children to identify factors that could aid primary care physicians to predict the need for extracorporeal membrane oxygenation (ECMO) earlier and consult the pediatric cardiologist promptly. Between October 2011 and September 2016, we retrospectively analyzed 60 patients aged 18 years or younger who were admitted to our pediatric emergency department with a definite diagnosis of acute myocarditis. Data on demographics, presentation, laboratory tests, electrocardiogram and echocardiography findings, treatment modalities, complications, and long-term outcomes were obtained. During the study period, 60 patients (32 male, 28 female; mean age, 8.8 ± 6.32 years) were diagnosed with acute myocarditis. Fever, cough, and chest pain were the most common symptoms (68.3%, 56.7%, and 53.3%, resp.). Arrhythmia and left ventricular ejection fraction (LVEF) < 60%, vomiting, weakness, and seizure were more common in the ECMO group than in the non-ECMO group, with statistical significance (P < 0.05). Female sex, vomiting, weakness, seizure, arrhythmia, and echocardiography showing LVEF < 60% may predict the need for ECMO. Initial serum troponin-I cutoff values greater than 14.21 ng/mL may also indicate the need for ECMO support for children with acute myocarditis.

Left ventricular end-diastolic dimension as a predictive factor of outcomes in children with acute myocarditis

In this study, we sought predictors of mortality in children with acute myocarditis and of incomplete recovery in the survivor group. We classified our patients into three groups according to their outcomes at last follow-up: full recovery was classified as group I, incomplete recovery was classified as group II, and death was classified as group III. In total, 55 patients were enrolled in the study: 33 patients in group I, 11 patients in group II, and 11 patients in group III. The initial left ventricular fractional shortening - left ventricular fractional shortening - was significantly lower in group III (p=0.001), and the left ventricular end-diastolic dimension z score was higher in groups II and III compared with group I (p=0.000). A multivariate analysis showed that the left ventricular end-diastolic dimension z score (odds ratio (OR), 1.251; 95% confidence interval (CI), 1.004-1.559), extracorporeal membrane oxygenation (OR, 9.842; 95% CI, 1.044-92.764), and epinephrine infusion (OR, 18.552; 95% CI, 1.759-195.705) were significant predictors of mortality. The left ventricular end-diastolic dimension z score was the only factor that predicted incomplete recovery in the survivor group (OR, 1.360; 95% CI, 1.066-1.734; p=0.013). The receiver operating characteristic curve of the left ventricular end-diastolic dimension z score at admission showed a cut-off level of 3.01 for predicting mortality (95% CI, 0.714-0.948). In conclusion, a high left ventricular end-diastolic dimension z score on admission was a significant predictor of worse outcomes, both regarding mortality and incomplete recovery.

Infant acute myocarditis mimicking acute myocardial infarction

Myocarditis is an inflammatory disease of the myocardium with heterogeneous clinical manifestations and progression. In clinical practice, although there are many methods of diagnosis of acute myocarditis, the diagnosis remains an embarrassing dilemma for clinicians. The authors report the case of 9-month-old infant who was brought to the Pediatric Emergency Department with sudden onset dyspnea. Examination disclosed heart failure and resuscitation was undertaken. The electrocardiogram showed an ST segment elevation in the anterolateral leads with a mirror image. Cardiac enzyme tests revealed a significant elevation of troponin and creatine phosphokinase levels. A diagnosis of acute myocardial infarction was made, and heparin therapy was prescribed. The infant died on the third day after admission with cardiogenic shock. The autopsy showed dilatation of the ventricles and massive edema of the lungs. Histological examinations of myocardium samples revealed the presence of a marked lymphocytic infiltrate dissociating myocardiocytes. Death was attributed to acute myocarditis. The authors call attention to the difficulties of differential diagnosis between acute myocarditis and acute myocardial infarction especially in children, and to the important therapeutic implications of a correct diagnosis.

Heart Failure and Mortality of Adult Survivors from Acute Myocarditis Requiring Intensive Care Treatment - A Nationwide Cohort Study

Background The correlation between severity and long-term outcomes of pediatric myocarditis have been reported, however this correlation in adults has rarely been studied. Materials and Methods This nationwide population-based cohort study used data from the National Health Insurance Research Database in Taiwan. Patients aged < 75 and > 18 years admitted to an intensive care unit due to acute myocarditis were enrolled and divided into three groups according to mechanical circulatory support (MCS) after excluding major comorbidities. All-cause mortality, cardiovascular death, and heart failure hospitalization were evaluated from January 1, 2001 to December 31, 2011. Results There were 1145 patients with acute myocarditis (mean age 40.2 years, SD: 14.8 years), of which 851 did not require MCS, 99 underwent intra-aortic balloon pump (IABP) support, and 195 extracorporeal membrane oxygenation (ECMO) support. There was no significant difference in heart failure hospitalization between the three groups after index admission. The incidence of cardiovascular death after discharge ranged from 10 % to 22%, which was highest in the ECMO group, and was also significantly different between the three groups within 3 months (p<0.001) but it disappeared after 3 months (p=0.458). The trend was also noted in incidence of all-cause mortality. Conclusions The severity of acute myocarditis did not affect long-term outcomes, however, it was associated with cardiovascular/all-cause death within 3 months after discharge.

Impact of Extracorporeal Membrane Oxygenation on Acute Fulminant Myocarditis-related Hemodynamic Compromise Arrhythmia in Children

BACKGROUND

Acute fulminant myocarditis (AFM) commonly presents as abrupt cardiogenic shock with or without dysrhythmia. This study evaluated the impact of extracorporeal membrane oxygenation (ECMO) on AFM-related hemodynamic compromise dysrhythmias. We also reported the clinical experience of AFM at our hospital.

METHODS

Eighteen children diagnosed with AFM were enrolled. Demographic variables, laboratory data, and clinical courses were reviewed. Thirteen surviving patients with hemodynamic compromise arrhythmia [complete atrioventricular block (CAVB) or ventricular tachycardia (VT)] during hospitalization were divided into Group A (ECMO group; n = 7) and Group B (non-ECMO group; n = 6).

RESULTS

The overall survival rate was 78% (14/18). There were no cases of mortality after ECMO was introduced at our hospital. Common symptoms at diagnosis included general malaise (94%), gastrointestinal symptoms (89%), chest pain (56%), shortness of breath (56%), and seizure/syncope (56%). In addition to abnormal cardiac enzyme levels, all patients displayed elevated alanine aminotransferase levels during early disease stages. Electrocardiography at diagnosis revealed dysrhythmia in 15 patients, namely, CAVB in 11 patients (61%) and VT in four patients (22%). During hospitalization, the dysrhythmia shifted from CAVB to VT in 10 patients and from sinus tachycardia to VT in one patient. New episodes of VT were common (overall occurrence rate, 83%). Although myocardial damage and dysfunction were more severe in Group A, the time to rhythm recovery in this group was shorter than that in Group B (median time, 1.7 days vs. 7.35 days, p = 0.045). All surviving patients had normal ventricular function at 6-month follow-up.

CONCLUSION

Hemodynamic compromise arrhythmia is common in AFM patients and may cause rapid deterioration. Simply correcting sinus rhythm is not always sufficient because of myocardium instability. Timely use of ECMO can improve the survival rate and shorten the time to recapture sinus rhythm in AFM patients with CAVB or VT.

T-cell immunity in myocardial inflammation: pathogenic role and therapeutic manipulation

T-cell-mediated immunity has been linked not only to a variety of heart diseases, including classic inflammatory diseases such as myocarditis and post-myocardial infarction (Dressler's) syndrome, but also to conditions without an obvious inflammatory component such as idiopathic dilated cardiomyopathy and hypertensive cardiomyopathy. It has been recently proposed that in all these conditions, the heart becomes the focus of T-cell-mediated autoimmune inflammation following ischaemic or infectious injury. For example, in acute myocarditis, an inflammatory disease of heart muscle, T-cell responses are thought to arise as a consequence of a viral infection. In a number of patients, persistent T-cell-mediated responses in acute viral myocarditis can lead to autoimmunity and chronic cardiac inflammation resulting in dilated cardiomyopathy. In spite of the major progress made in understanding the mechanisms of pathogenic T-cell responses, effective and safe therapeutic targeting of the immune system in chronic inflammatory diseases of the heart has not yet been developed due to the lack of specific diagnostic and prognostic biomarkers at an early stage. This has also prevented the identification of targets for patient-tailored immunomodulatory therapies that are both disease- and organ-selective. In this review, we discuss current knowledge of the development and functional characteristics of pathogenic T-cell-mediated immune responses in the heart, and, in particular, in myocarditis, as well as recent advances in experimental models which have the potential to translate into heart-selective immunomodulation.

LINKED ARTICLES

This article is part of a themed section on Targeting Inflammation to Reduce Cardiovascular Disease Risk. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.22/issuetoc and http://onlinelibrary.wiley.com/doi/10.1111/bcp.v82.4/issuetoc.

Coronary Artery Dilatation in Viral Myocarditis Mimics Coronary Artery Findings in Kawasaki Disease

Coronary artery (CA) dilatations are typical to Kawasaki disease (KD) in the pediatric population. CA involvement is a useful feature to help establish the diagnosis of KD. Since myocarditis is omnipresent in the acute phase of KD, we sought to investigate whether viral myocarditis may cause CA dilatation. This retrospective study reviewed 14 consecutive patients diagnosed with acute myocarditis at CHU Sainte-Justine, Montreal. KD diagnosis was excluded for all patients. All echocardiography studies were reviewed by an independent experienced echocardiographer for CA size and myocardial function parameters. CA involvement was classified under three categories: definite dilatation (Z-score ≥2.5 in one or more CA), occult dilatation (Z-score variation ≥2 points for the same CA on two different echocardiograms, but maximum Z-score always <2.5), and no dilatation otherwise. Demographics, laboratory values, microbial etiology testing, and diagnostic studies were collected from medical records. Mean age at presentation was 1.67 ± 3.22 years, where 11/14 (78 %) presented with acute and three with subacute myocarditis. Five (36 %) patients had normal CA measurements, six (43 %) had occult dilatation, and three (21 %) had definite dilatation. Maximal CA Z-score was within the first 8 days of presentation. Patients with viral myocarditis can present CA dilatation during the acute phase of the illness. This finding should be taken into account when KD diagnosis is being based on the CA involvement as the two illnesses may present with similar features.

Usefulness of arrhythmias as predictors of death and resource utilization in children with myocarditis

Myocarditis in children can result in significant morbidity and mortality, yet limited prognostic data exist. The aim of this study was to test the hypothesis that pediatric patients with arrhythmias during hospitalization for acute myocarditis have worse outcomes and increased resource utilization. A retrospective study using the Pediatric Health Information System database was performed to examine the effects of clinically significant arrhythmias on in-hospital mortality, length of stay, and costs per day. Data were obtained for children ≤18 years of age, discharged from January 1, 2004 to March 31, 2013, with a diagnosis of myocarditis. Clinically significant tachyarrhythmia was defined as supraventricular tachycardia, atrial fibrillation or flutter, or ventricular tachycardia or fibrillation in patients receiving antiarrhythmic medications or cardioversion. Clinically significant bradyarrhythmia was defined as second-degree, complete, or other heart block for which a pacemaker was placed. Multivariable analyses were performed. A total of 2,041 subjects with myocarditis were identified. Tachyarrhythmias were reported in 234 (11.5%) and bradyarrhythmias in 22 (1.1%). Overall mortality was 8.7%. In multivariable analyses, after considering the effects of gender, age at admission, geographic region, year and month of admission, presence of congenital heart disease or an identified virus, and use of steroids, nonsteroidal anti-inflammatories, or inotropes, and after controlling for clustering by institution, tachyarrhythmias were associated with a 2.3 times increase in the odds of mortality (95% confidence interval 1.6 to 3.3, p < 0.001), a 58% increase in length of stay (95% confidence interval 38% to 82%, p < 0.001), and a 28% increase in costs per day (95% confidence interval 15% to 43%, p < 0.001). Bradyarrhythmia was not associated with mortality, length of stay, or costs per day. In conclusion, tachyarrhythmias are associated with significant increases in mortality and resource utilization in children with myocarditis.

Effects of the elective introduction of extracorporeal membrane oxygenation on outcomes in pediatric myocarditis cases

Aim

To investigate the necessary indicators to diagnose pediatric myocarditis and choose appropriate candidates for extracorporeal membrane oxygenation therapy.

Methods

We retrospectively reviewed the medical records of children aged <16 years of age who were diagnosed with myocarditis and admitted to the pediatric intensive care unit in a Japanese children's hospital from 2002 to 2013. We collected demographic data and symptoms and signs during the entire clinical course, investigated the survival and neurological outcomes, and identified the predictors of death.

Results

Twenty-nine patients (median age, 5 years) met the inclusion criteria. Fever and gastrointestinal symptoms occurred in approximately 80% of the patients as initial symptoms and central nervous system symptoms were the most frequent symptom on emergency presentation (41%). Extracorporeal membrane oxygenation was administered to 16 patients; of these, five died. Of the 24 surviving patients, 23 achieved favorable neurological outcomes. Four of eight patients died following cardiopulmonary resuscitation-triggered extracorporeal membrane oxygenation, and one of eight died following elective extracorporeal membrane oxygenation. Multivariate analysis using stepwise logistic regression analysis revealed creatinine level as an independent predictor of death.

Conclusion

It is important to consider myocarditis when evaluating children with gastrointestinal or central nervous system symptoms. The elective introduction of extracorporeal membrane oxygenation before the completion of end-organ dysfunction has a positive effect on outcomes in pediatric myocarditis cases. Transfer to an institution that can initiate extracorporeal membrane oxygenation support should be promptly considered when managing pediatric myocarditis.

Nucleotide differences of coxsackievirus B3 and chronic myocarditis

The in vivo mechanisms in chronic myocarditis remain unclear. The aim of the current study was to clarify the genomic difference of amyocarditic (CB3O) and myocarditic (CB3M) coxsackievirus B3 (CB3) and the pathogenesis of in vivo mechanisms in chronic myocarditis. We examined the histopathology of CB3-inoculated wild-type (WT) and severe combined immunodeficient (SCID) mice with and without adoptive transfer of lymphocytes. There were no differences in viral growth between CB3O and CB3M. There were four to six nucleotide differences in the sequence of CB3O in comparison with the known CB3M. The difference in virus sequence between CB3O and CB3M was very minimal. The changes were located in 1A, 1C, and 1D regions, which encode the structural capsid proteins. Definite myocarditis developed in WT C3H (H-2(k)) inoculated with CB3M. On the contrary, trivial or mild myocarditis occurred in WT C3H mice inoculated with CB3O. In SCID C3H and SCID C57BL/6 (H-2(b)) mice, definite myocarditis developed by inoculation with both CB3O and CB3M. Myocardial lesion was less severe in the mice infected with CB3O than in those with CB3M. After anti-CD8 antibody treatment, myocarditis was easily induced in mice originally showing resistance to infection. In addition, chronic myocarditis developed in CB3O-infected SCID C3H mice reconstituted with CB3M-sensitized splenocytes of WT C3H mice. The development of chronic myocarditis primarily depends on the presence or absence of the virus genome, and secondarily on the complex interaction between virus virulence and immunological background of the host. CB3 infection may cause chronic myocarditis with ongoing inflammation with or without viral persistence.

The autopsy study of 553 cases of sudden cardiac death in Chinese adults

Despite a recent epidemiological study reporting a lower incidence of sudden cardiac death (SCD) in China as compared with that in Western countries, the exact causes of SCD are still unknown. Using a uniform review protocol and diagnostic criteria, a retrospective autopsy study identified 553 cases of SCD in 14,487 consecutive autopsies from eight regions in China representing different geographic and population features. Their ages ranged from 18 to 80 years (median 43.0 years) with a ratio of 4.3/1.0 for male/female. Out-of-hospital deaths and unwitnessed cases accounted for 74.3 and 22.6 %, respectively. The main causes of death were coronary atherosclerotic disease (CAD 50.3 %), myocarditis (14.8 %), and hypertrophic cardiomyopathy (4.5 %), with unexplained sudden death accounting for 12.1 % of the cases. CAD had a proportion of 10.4 % in victims <35 years, lower as compared with 59.0 and 83.0 % in victims aged 35-54 and in victims ≥55 years. On the other hand, myocarditis and unexplained sudden death were major causes and accounted for 34.7 and 22.5 % in victims <35 years. In order to differentiate the degree of the cause-effect relationship between autopsy findings and sudden death, a grading method was used in this series and characterized 24.3 % of findings as certain, 52.9 % as highly probable, and 22.8 % as uncertain. Our data indicated that there most likely are less CAD but more myocarditis and unexplained sudden death in Chinese youth with SCD than in populations from Western countries. Molecular genetic testing should be conducted in those cases with uncertain findings and unexplained sudden death in routine autopsy.