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

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.

Recent Trends in Incidence and Outcomes for Acute Myocarditis in Children in the United States

Lack of defined diagnostic criteria for acute myocarditis makes its diagnosis dependent on clinical suspicion. The objective of this study was to the current trends in demographics, clinical manifestations, treatments, and outcomes in the United States for children hospitalized with acute myocarditis. This retrospective study was conducted using data collected from the Pediatric Health Information System database for the years 2014 to 2020. We included patients 21 years of age or younger with acute myocarditis. The statistical analysis was performed using chi-squared test and continuous variables using Mann–Whitney's U-test for continuous data comparisons. We found 1,199 patients with acute myocarditis. About 60% of patients required admission to the intensive care unit (ICU). The median hospital length of stay was 4 days for all patients and 6 days for ICU patients. Two hundred sixty-five (22.1%) patients required invasive mechanical ventilation, 127 (10.6%) required extracorporeal membrane oxygenation, 33 (2.8%) required ventricular assist device, and 22 (1.8%) required cardiac transplantations. Milrinone was the most used vasoactive agent. The overall hospital mortality was 2.3%. Intravenous immunoglobulin (IVIG) infusion use decreased during the study period. On multivariate analysis, vasoactive medication use (p < 0.01) and arrhythmia (p = 0.02) were independently associated with increased odds of mortality. IVIG use (p = 0.01) was associated with decreased odds of mortality. Despite high morbidity and frequent need for advanced life support measures, the survival outcomes of acute myocarditis in children are favorable. Vasoactive medication support and occurrence of arrythmia were independently associated with mortality, most likely due to disease severity. Administration of IVIG was independently associated with reduced mortality. The Clinical trial registration is not applicable.

Extracorporeal Membrane Oxygenation Cannulation Timing in the Pediatric Myocarditis Population: An Exploratory Analysis From the Extracorporeal Life Support Organization Registry

Children presenting with acute myocarditis may experience rapid clinical deterioration requiring extracorporeal membrane oxygenation (ECMO); however, our understanding of best practices and timing of ECMO initiation are lacking. We explored the relationships between pre-cannulation factors and survival in this high-acuity patient population.

DESIGN

Retrospective review of a large international registry. Primary outcome was survival to hospital discharge, stratified by incident cardiac arrest (CA) prior to ECMO and time to cannulation after intubation.

SETTING AND SUBJECTS

The Extracorporeal Life Support Organization registry was queried for patients less than or equal to 18 years old receiving ECMO support for myocarditis between 2007 and 2018. Exclusion criteria included being nonindex runs, non-venoarterial ECMO or missing data points for main variables studied.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Population characteristics and survival were compared using t test, Wilcoxon rank-sum test, or Fisher exact test. Multivariable logistic regression was used for significant factors in the unadjusted logistic regression. Among 506 index ECMO runs in pediatric patients with myocarditis, survival for the cohort was 72%, with no difference between early and late eras (2007-2012 vs 2013-2018; p = 0.69). Survivors demonstrated higher pre-ECMO pH levels as well as shorter intubation-to-cannulation (ITC) times (3 hr [interquartile range (IQR)], 1-14 hr vs 6 hr [IQR, 2-20 hr]; p = 0.021). CA occurred within 24 hours prior to ECMO cannulation, including extracorporeal cardiopulmonary resuscitation, in 54% of ECMO runs (n = 273). Accounting for the interaction between pre-ECMO CA occurrence and ITC time, longer ITC time remained associated with lower survival for patients who did not experience a CA prior to ECMO, with adjusted odds ratio of 0.09 (IQR, 0.02-0.40; p = 0.002) for ITC time greater than or equal to 18 hours.

CONCLUSIONS

The results of this multicenter analysis of ECMO utilization and outcomes for pediatric myocarditis suggest that patients approaching ECMO cannulation who have not experienced CA may have better survival outcomes if cannulated onto ECMO early after intubation.

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.

Are clinical features and cardiac biomarkers at admission related to severity in pediatric acute myocarditis?: Clinical features and cardiac biomarkers in pediatric acute myocarditis

OBJECTIVES

To evaluate the factors associated with intensive care requirement and mortality in pediatric myocarditis.

METHODS

Children aged 28 days to 18 years who were diagnosed with acute myocarditis in a pediatric emergency department between January 2010 and September 2020 were enrolled in the study retrospectively. Demographic and clinical features, cardiac biomarkers, and imaging findings were evaluated. Length of hospital stay, need for hospitalization in the pediatric intensive care unit (PICU), treatments, and survival outcomes were recorded. To define the severity of disease, three groups were created and the data were compared in terms of clinical, laboratory, and imaging findings. The patients treated in the pediatric ward were compared with those hospitalized in the PICU. Ventricular dysfunction was defined in patients with a left ventricular ejection fraction (LVEF) of <50% and these patients were compared with those who had an LVEF of >50%. Also, survivor and non-survivor patients were compared.

RESULTS

A total number of 62 patients with a median age of 8 years were included. Chest pain and tachycardia were the most common findings on physical examination. The mean LVEF was 59.3 ± 13.0% at admission. Of the patients, 17 were hospitalized in the PICU (27.4%). Chest pain was more common in patients hospitalized in the pediatric ward (p<0.001), and hypotension, vomiting, arrhythmia, were more common and LVEF was lower in patients in the PICU (p = 0.017, p = 0.008, p = 0.006, and p = 0.025, respectively). The children treated in the PICU were younger than those in the pediatric ward (p = 0.009). Troponin I levels were significantly higher in the pediatric ward (p = 0.035), and brain natriuretic peptide (BNP) levels were higher in patients in the PICU (p = 0.012). Death occurred in four patients. Hypotension and vomiting were significantly more common in non-survivors (p = 0.020 and 0.004, respectively). Inotropes and intravenous immunoglobulin (IVIG) were more commonly used in non-survivors (p = 0.001 and p = 0.015, respectively). BNP levels were higher in non-survivors (p = 0.008), and troponin I levels were not different between survivors and non-survivors (p = 0.260).

CONCLUSION

In pediatric acute myocarditis, lower LVEF, increased BNP, as well as the presence of hypotension and arrhythmia were found to be related to intensive care requirement. Hypotension and vomiting were found to be more common in non-survivors. Due to the possibility of rapidly worsening disease, physicians should be alert to the presence of these findings.

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSIONS

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

Frequency of Extracorporeal Membrane Oxygenation Support and Outcomes After Implementation of a Structured PICU Network in Neonates and Children: A Prospective Population-Based Study in the West of France

OBJECTIVES

To describe the frequency and outcomes on the use of extracorporeal membrane oxygenation (ECMO) among critically ill neonates and children within a structured pediatric critical care network in the West of France. To assess the optimality of decision-making process for patients primarily admitted in non-ECMO centers.

DESIGN

Observational prospective population-based study from January 2015 to December 2019.

PATIENTS

Neonates over 34 weeks of gestational age, weighing more than 2,000 g and children under 15 years and 3 months old admitted in one of the 10 units belonging to a Regional Pediatric Critical Care Network.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Eight-thousand one hundred eighty-nine children and 3,947 newborns were admitted within one of the 10 units of the network over the study period. Sixty-five children (8.1% [95% CI, 6.2-10‰]) and 35 newborns (9.4% [95% CI, 6.4-12%]) required ECMO support. Of these patients, 31 were first admitted to a non-ECMO center, where 20 were cannulated in situ (outside the regional ECMO center) and 11 after transfer to the ECMO regional center. Cardiogenic shock, highest serum lactate level, and cardiac arrest prior to first phone call with the regional ECMO center were associated with higher rate of in situ cannulation. During the study period, most of the patients were cannulated for underlying cardiac issue (42/100), postoperative cardiac surgery instability (38/100), and pediatric (10/100) and neonatal (10/100) respiratory distress syndrome. Patients primarily admitted in non-ECMO centers or not had similar 28-day post-ICU survival rates compared with those admitted in the referral ECMO center (58% vs 51%; p = 0.332). Pre-ECMO cardiac arrest, ECMO, and lower pH at ECMO onset were associated with lower 28-day post-ICU survival.

CONCLUSIONS

Our local results suggest that a structured referral network for neonatal and pediatric ECMO in the region of Western France facilitated escalation of care with noninferior (or similar) early mortality outcome. Our data support establishing referral networks in other equivalent regions.

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.

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.

Evolution of acute myocarditis in a pediatric population: An MRI based study

BACKGROUND

Cardiac Magnetic Resonance (CMR) data regarding myocarditis presentation and disease course is still lacking in pediatric patients. We evaluate baseline CMR and evolution of functional and tissue abnormalities in children with acute myocarditis.

METHODS

CMR was performed in 125 patients with clinical diagnosis of acute myocarditis. Clinical follow-up was performed for a median of 498 (214-923) days.

RESULTS

LVEF was depressed (<55%) in 56 cases (45%) upon baseline CMR. LGE was found in 93 patients (77%) of cases. LGE was exclusively subepicardial in 29 patients (23%), while other LGE patterns (midwall/mixed) were present in 64 (51%). CMR was repeated in 92 (74%) patients. 67% presented recover of function at a median of 170 (70-746) days after onset of symptoms. Midwall/mixed LGE pattern had a statistically significant correlation with absent recover of function (OR 0.20 p 0.036). Thirteen patients (16%) had recovery from LV dysfunction but with persistence of LGE. Sub-epicardial pattern of LGE (OR 3.33, 95% CI 1.08-10.2, p = 0.036) and the presence of fever at admission (OR 4.67, 95% CI 1.16-18.7, p = 0.03) were associated with a significantly higher likelihood of complete normalization while midwall/mixed LGE pattern was associated with non-recovery.

CONCLUSIONS

In pediatric myocarditis, midwall/mixed LGE pattern is associated with absent recover of function. Patients with recover of function may still have persistence of LGE, while a complete recovery from functional and tissue abnormalities is found only in a third of patients. Midwall/mixed pattern of LGE at first MRI was associated to worse outcome.

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.

Factors Associated With In-hospital Mortality of Children With Acute Fulminant Myocarditis on Extracorporeal Membrane Oxygenation

Aim: To analyze the factors associated with in-hospital mortality of children with acute fulminant myocarditis on venoarterial extracorporeal membrane oxygenation (VA-ECMO). Methods: This was a retrospective cohort study using chart reviews of patients diagnosed with acute fulminant myocarditis at the pediatric intensive care unit of two tertiary medical centers between January 1, 2005 and December 31, 2017. The inclusion criteria for this study were: (1) age from 1 month to 18 years; (2) diagnosed with acute myocarditis; (3) cardiogenic shock and need vasoactive-inotropic score ≥20 within 48 h after the use of vasoactive-inotropic agents; and (4) the need for ECMO placement. Results: Thirty-three children with acute fulminant myocarditis who needed ECMO were included. Clinical parameters were retrospectively reviewed. The overall survival rate was 69.6%. Higher levels of pre-ECMO troponin-I and pre-ECMO lactate, and lower post-ECMO left ventricular ejection fraction (LVEF) were significantly associated with in-hospital mortality in univariate analysis. Only higher pre-ECMO lactate and lower post-ECMO LVEF remained as predictors for in-hospital mortality in multivariate analysis. The areas under the curve of pre-ECMO lactate and post-ECMO LVEF in predicting survival were 0.848 (95% CI, 0.697-0.999, p = 0.002) and 0.824 (95% CI, 0.704-0.996, p = 0.01), respectively. A pre-ECMO lactate level of 79.8 mg/dL and post-ECMO LVEF of 39% were appropriate cutoff points to predict mortality. Conclusion: Pre-ECMO lactate level was associated with mortality in children with acute fulminant myocarditis, with an optimal cutoff value of 79.8 mg/dL. After VA-ECMO implantation, post-ECMO LVEF was associated with mortality, with an optimal cutoff value of 39%. The use of LVADs or urgent heart transplantation should be considered if the post-ECMO LVEF does not improve.