National Trends, Gender, Management, and Outcomes of Patients Hospitalized for Myocarditis

Myocarditis incidence and hospital mortality from 2007 to 2022: insights from a nationwide registry

OBJECTIVES

To investigate the burden of disease of myocarditis in Germany and identify similarities and differences in myocarditis with or without COVID-19.

METHODS

All patients hospitalized with myocarditis in Germany were included in this nationwide retrospective analysis. Data were retrieved from the Federal Statistical Office of Germany (DESTATIS) for the years from 2007 to 2022. The primary endpoint was hospital mortality.

RESULTS

A total of 88,159 patients hospitalized with myocarditis were analyzed. Annual cases increased from 5100 in 2007 to 6593 in 2022 (p < 0.001 for trend) with higher incidence during winter months. Incidence per 100,000 inhabitants was 6.2 in 2007 rising to 7.8 in 2022 (p < 0.001 for trend). Hospital mortality remained constant at an average of 2.44% (p = 0.164 for trend). From 2020 to 2022, 1547/16,229 (9.53%) patients were hospitalized with both, myocarditis and COVID-19 (incidence 0.62/100,000 inhabitants and 180/100,000 hospitalizations with COVID-19). These patients differed significantly in most patient characteristics and had a higher rate of hospital mortality compared to myocarditis without COVID-19 (12.54% vs. 2.26%, respectively, p < 0.001).

CONCLUSIONS

Myocarditis hospitalizations were slowly rising over the past 16 years with hospital mortality remaining unchanged. Incidence of hospitalizations with combined myocarditis and COVID-19 was low, but hospital mortality was high.

Sex-Based Differences in Clinical Characteristics of Patients with Acute Myocarditis: A Cohort Study

BACKGROUND

This study investigated sex differences in acute myocarditis patients during index hospitalization.

METHODS

We included 365 patients with acute myocarditis, hospitalized with continuous monitoring at the intensive care unit from 2000-2023 into the Basel Myocarditis Cohort study. We compared sex differences in clinical presentation, the presenting electrocardiogram, prior medical history, inflammatory and cardiac biomarkers, cardiac imaging, arrhythmia occurrence, and short- to midterm outcomes.

RESULTS

Mean age was 41.3 years, and 26.3% were female. Compared with men, women were older (median 49.7 vs 38.3 years, P < .001) at the time of diagnosis and presented more frequently with dyspnea (41 vs 26%, P = .013) and a higher Killip class (P = .011). In the presenting electrocardiogram, men had a higher occurrence of diffuse ST-elevation (38 vs 9%, P < .001) and PQ-depression (31 vs 20%, P = .042), compared with women. Women had higher N-terminal pro B-type natriuretic peptide levels (1180 vs 387 ng/L, P = .015), lower cardiac troponin T levels (389 vs 726 ng/L, P = .006), and fewer segments with nonischemic late gadolinium enhancement on cardiac magnetic resonance imaging (1 vs 3, P = .005), but similar left ventricular ejection fraction (55 vs 55%, P = .629), compared with men. Overall, hospital stay was longer in women compared with men (7 vs 5 days, P = .018), with a similar length of intensive care unit stay (2.6 vs 2.7 days, P = .922). Women more often developed severe arrhythmia (8.3 vs 2.2%, P = .015) and heart failure during the hospitalization (31.3 vs 16.4%, P = .003).

CONCLUSION

Compared with men, women with acute myocarditis were older at the time of diagnosis, presented more often with heart failure, and had an increased frequency of severe arrhythmia.

Unveiling the Diagnostic Value of Strain Parameters Across All 4 Cardiac Chambers in Patients With Acute Myocarditis With Varied Ejection Fraction: A Cardiovascular Magnetic Resonance Feature-Tracking Approach

BACKGROUND

This study assesses the diagnostic utility of strain parameters from cardiovascular magnetic resonance feature tracking across all cardiac chambers in patients with acute myocarditis, stratified by ejection fraction.

METHODS AND RESULTS

Our cohort included 65 patients with acute myocarditis and 25 healthy controls; all underwent cardiac magnetic resonance imaging. Patients were divided into 2 groups based on left ventricular ejection fraction (EF)with a 55% cutoff: acute myocarditis with preserved EF, EF ≥55%, n=48; and acute myocarditis with reduced EF, EF <55%, n=17. The control group matched for age and sex. Cardiovascular magnetic resonance feature tracking evaluated strain parameters across all cardiac chambers. Both acute myocarditis with preserved EF and acute myocarditis with reduced EF groups showed significant decreases in left atrial peak early negative strain rate compared with controls. The acute myocarditis with reduced EF group had significantly reduced left ventricular circumferential strain relative to acute myocarditis with preserved EF and controls. Receiver operating characteristic curve analysis confirmed the diagnostic accuracy in distinguishing patients with acute myocarditis with preserved EF from controls, with left atrial peak early negative strain rate achieving 92.9% specificity, left ventricular circumferential strain demonstrating an area under the curve of 0.832, and similarly effective results for left ventricular longitudinal strain and right ventricular longitudinal strain. Additionally, left atrial peak early negative strain rate and left ventricular circumferential strain showed significant correlations with troponin I levels, indicating myocardial injury.

CONCLUSIONS

Cardiovascular magnetic resonance feature-tracking-derived strain parameters, particularly left atrial peak early negative strain rate and left ventricular circumferential strain, effectively diagnose acute myocarditis across different EFs, enhancing diagnostic accuracy and facilitating early detection, notably in patients with preserved EF.

The Influence of Biological Sex on Presentation and Outcomes of Acute Myocarditis: A Systematic Review and Meta-Analysis

There is growing evidence of sex-related differences in the epidemiology and pathophysiology of cardiovascular diseases. This is the first systematic review and meta-analysis that aimed to highlight the sex-specific differences in the clinical features and outcomes of acute myocarditis. Electronic searches were performed on Scopus, Embase, and PubMed from inception up to June 2023 to identify studies comparing the clinical features and outcomes of acute myocarditis in males and females. Both qualitative and quantitative summaries were conducted. In this systematic review and meta-analysis of 11 studies involving 34,791 patients presenting with acute myocarditis. Male patients, who comprised 69.8% of the entire pooled population, presented at a markedly younger age (mean difference: -8.99 years; 95% CI: -13.60, -4.38; p=0.0001). They also had significantly lower rates of hypertension, diabetes mellitus, and coronary artery disease compared to female patients (p<0.01). Male patients were more likely to present with ST elevation (RR: 2.57 [1.38, 4.79]; p=0.003) and higher C-reactive protein levels (RR: 3.04 [2.75, 3.34]; p<0.00001) compared to female patients. This review underscores the crucial sex-specific evaluation in acute myocarditis, necessitating tailored approaches in assessment and diagnostic evaluation, and emphasizing the need for additional research in this domain.

Gender Effect on Clinical Profiles, Pharmacological Treatments and Prognosis in Patients Hospitalized for Heart Failure

Heart failure (HF) is a significant disease affecting 1-2% of the general population. Despite its general aspects, HF, like other cardiovascular diseases, presents various gender-specific aspects in terms of etiology, hemodynamics, clinical characteristics, therapy, and outcomes. As is well known, HF with preserved ejection fraction more frequently affects females, with diabetes and arterial hypertension representing the most critical determinants of HF. On the other hand, women are traditionally underrepresented in clinical trials and are often considered undertreated. However, it is not clear whether such differences reflect cultural behaviors and clinical inertia or if they indicate different clinical profiles and the impact of sex on hard clinical outcomes. We aimed to review the sex-related differences in patients affected by HF.

Sex differences in myocarditis hospitalizations: Rates, outcomes, and hospital characteristics in the National Readmission Database

Inflammation of the myocardium, or myocarditis, presents with varied severity, from mild to life-threatening such as cardiogenic shock or ventricular tachycardia storm. Existing data on sex-related differences in its presentation and outcomes are scarce. Using the Nationwide Readmission Database (2016-2019), we identified myocarditis hospitalizations and stratified them according to sex to either males or females. Multivariable regression analyses were used to determine the association between sex and myocarditis outcomes. The primary outcome was in-hospital mortality, and the secondary outcomes included sudden cardiac death (SCD), cardiogenic shock (CS), use of mechanical circulatory support (MCS), and 90-day readmissions. We found a total of 12,997 myocarditis hospitalizations, among which 4,884 (37.6 %) were females. Compared to males, females were older (51 ± 15.6 years vs. 41.9 ± 14.8 in males) and more likely to have connective tissue disease, obesity, and a history of coronary artery disease. No differences were noted between the two groups with regards to in-hospital mortality (adjusted odds ratio [aOR] 1.20; confidence interval [CI] 0.93-1.53; P = 0.16), SCD (aOR:1.18; CI 0.84-1.64; P = 0.34), CS (aOR: 1.01; CI 0.85-1.20;P = 0.87), or use of MCS (aOR: 1.07; CI:0.86-1.34; P = 0.56). In terms of interventional procedures, females had lower rates of coronary angiography (aOR: 0.78; CI 0.70-0.88; P < 0.01), however, similar rates of right heart catheterization (aOR 0.93; CI:0.79-1.09; P = 0.36) and myocardial biopsy (aOR: 1.16; CI:0.83-1.62; P = 0.38) compared to males. Additionally, females had a higher risk of 90-day all-cause readmission (aOR: 1.25; CI: 1.16-1.56; P < 0.01) and myocarditis readmission (aOR:1.58; CI 1.02-2.44; P = 0.04). Specific predictors of readmission included essential hypertension, congestive heart failure, malignancy, and peripheral vascular disease. In conclusion, females admitted with myocarditis tend to have similar in-hospital outcomes with males; however, they are at higher risk of readmission within 90 days from hospitalization. Further studies are needed to identify those at higher risk of readmission.

Mechanical Circulatory Support in Pediatric Myocarditis: Support Strategies and Outcomes in a Nationally Representative Cohort

Background

Myocarditis is a common cause of pediatric heart failure which may require mechanical circulatory support (MCS). The purpose of this study is to describe MCS strategies used in a nationwide cohort of pediatric patients with myocarditis, identify trends over time, and compare outcomes between MCS strategies.

Methods

This study utilized the Kids' Inpatient Database (KID), a national sample of administrative discharge data. KID admissions from 2003-2016 were queried using ICD-9/10 codes to identify those with a diagnosis of myocarditis. MCS outcomes were compared using logistic regression.

Results

Of 5,661 admissions for myocarditis, MCS was used in 424 (7.5%), comprised of extracorporeal membrane oxygenation (ECMO) in 312 (73.6%), including 32 (10.2%) instances of extracorporeal cardiopulmonary resuscitation (ECPR), temporary ventricular assist devices (tVAD) in 28 (6.6%), durable VAD (dVAD) in 42 (9.9%) and combination MCS in 42 (9.9%). MCS use increased over time (p=0.031), but MCS strategies did not significantly change. Mortality was high in the MCS group (28.3%). There was no difference in odds of death in the VAD only or combination MCS group compared to the non-ECPR ECMO group (p=0.07 and p=0.65, respectively).

Conclusion

MCS is used in 1 in 13 pediatric myocarditis cases, and MCS use is increasing over time with ECMO remaining the most frequently used modality. Mortality remains high in patients that receive MCS but does not differ between those receiving VAD or combination MCS as compared to non-ECPR ECMO on unadjusted analysis. Further prospective analysis is required to evaluate the relative effectiveness of MCS modalities in this disease.

Sex-based differences in late gadolinium enhancement among patients with acute myocarditis

OBJECTIVE

The aims of our study were to investigate the sex differences in late gadolinium enhancement (LGE) using cardiovascular magnetic resonance (CMR) in a single-centre cohort of consecutive patients with acute myocarditis (AM).

METHOD

This retrospective study performed CMR scans in 135 consecutive patients with AM that met the Lake Louise criteria. On CMR, LV ventricular strain functions were performed on conventional cine SSFP sequences. Besides myocardial strain measurements, myocardial scar location, extension, and size were assigned and quantified by LGE imaging.

RESULTS

There was no difference in age (age 42.51 ± 19.64 years vs 40.92 ± 19.94 years; p = 0.74) and cardiovascular risk profile between women and men. Despite similar comorbidities, women were more like to present with dyspnea (p = 0.001). Women demonstrated higher prevalence of septal LGE (p = 0.004) and increased global circumferential strain parameters (p = 0.008) in comparison with men. In multivariate analysis, female sex remained an independent determinant of septal LGE (β coefficient = -0.520, p = 0.001).

CONCLUSION

This is the first study reporting sex differences in LGE localization in AM. Women have more septal LGE involvement independent of age, cardiovascular risk factors, and CMR parameters. These findings further emphasize the sex-based differences in cardiovascular diseases.

Sex Differences in Heart Failure: What Do We Know?

Heart failure (HF) remains an important global health issue, substantially contributing to morbidity and mortality. According to epidemiological studies, men and women face nearly equivalent lifetime risks for HF. However, their experiences diverge significantly when it comes to HF subtypes: men tend to develop HF with reduced ejection fraction more frequently, whereas women are predominantly affected by HF with preserved ejection fraction. This divergence underlines the presence of numerous sex-based disparities across various facets of HF, encompassing aspects such as risk factors, clinical presentation, underlying pathophysiology, and response to therapy. Despite these apparent discrepancies, our understanding of them is far from complete, with key knowledge gaps still existing. Current guidelines from various professional societies acknowledge the existence of sex-based differences in HF management, yet they are lacking in providing explicit, actionable recommendations tailored to these differences. In this comprehensive review, we delve deeper into these sex-specific differences within the context of HF, critically examining associated definitions, risk factors, and therapeutic strategies. We provide a specific emphasis on aspects exclusive to women, such as the impact of pregnancy-induced hypertension and premature menopause, as these unique factors warrant greater attention in the broader HF discussion. Additionally, we aim to clarify ongoing controversies and knowledge gaps pertaining to the pharmacological treatment of HF and the sex-specific indications for cardiac implantable electronic devices. By shining a light on these issues, we hope to stimulate a more nuanced understanding and promote the development of more sex-responsive approaches in HF management.

Cytokinopathy with aberrant cytotoxic lymphocytes and profibrotic myeloid response in SARS-CoV-2 mRNA vaccine-associated myocarditis

Rare immune-mediated cardiac tissue inflammation can occur after vaccination, including after SARS-CoV-2 mRNA vaccines. However, the underlying immune cellular and molecular mechanisms driving this pathology remain poorly understood. Here, we investigated a cohort of patients who developed myocarditis and/or pericarditis with elevated troponin, B-type natriuretic peptide, and C-reactive protein levels as well as cardiac imaging abnormalities shortly after SARS-CoV-2 mRNA vaccination. Contrary to early hypotheses, patients did not demonstrate features of hypersensitivity myocarditis, nor did they have exaggerated SARS-CoV-2-specific or neutralizing antibody responses consistent with a hyperimmune humoral mechanism. We additionally found no evidence of cardiac-targeted autoantibodies. Instead, unbiased systematic immune serum profiling revealed elevations in circulating interleukins (IL-1β, IL-1RA, and IL-15), chemokines (CCL4, CXCL1, and CXCL10), and matrix metalloproteases (MMP1, MMP8, MMP9, and TIMP1). Subsequent deep immune profiling using single-cell RNA and repertoire sequencing of peripheral blood mononuclear cells during acute disease revealed expansion of activated CXCR3+ cytotoxic T cells and NK cells, both phenotypically resembling cytokine-driven killer cells. In addition, patients displayed signatures of inflammatory and profibrotic CCR2+ CD163+ monocytes, coupled with elevated serum-soluble CD163, that may be linked to the late gadolinium enhancement on cardiac MRI, which can persist for months after vaccination. Together, our results demonstrate up-regulation in inflammatory cytokines and corresponding lymphocytes with tissue-damaging capabilities, suggesting a cytokine-dependent pathology, which may further be accompanied by myeloid cell-associated cardiac fibrosis. These findings likely rule out some previously proposed mechanisms of mRNA vaccine--associated myopericarditis and point to new ones with relevance to vaccine development and clinical care.

Sex and gender differences in myocarditis and dilated cardiomyopathy: An update

In the past decade there has been a growing interest in understanding sex and gender differences in myocarditis and dilated cardiomyopathy (DCM), and the purpose of this review is to provide an update on this topic including epidemiology, pathogenesis and clinical presentation, diagnosis and management. Recently, many clinical studies have been conducted examining sex differences in myocarditis. Studies consistently report that myocarditis occurs more often in men than women with a sex ratio ranging from 1:2-4 female to male. Studies reveal that DCM also has a sex ratio of around 1:3 women to men and this is also true for familial/genetic forms of DCM. Animal models have demonstrated that DCM develops after myocarditis in susceptible mouse strains and evidence exists for this progress clinically as well. A consistent finding is that myocarditis occurs primarily in men under 50 years of age, but in women after age 50 or post-menopause. In contrast, DCM typically occurs after age 50, although the age that post-myocarditis DCM occurs has not been investigated. In a small study, more men with myocarditis presented with symptoms of chest pain while women presented with dyspnea. Men with myocarditis have been found to have higher levels of heart failure biomarkers soluble ST2, creatine kinase, myoglobin and T helper 17-associated cytokines while women develop a better regulatory immune response. Studies of the pathogenesis of disease have found that Toll-like receptor (TLR)2 and TLR4 signaling pathways play a central role in increasing inflammation during myocarditis and in promoting remodeling and fibrosis that leads to DCM, and all of these pathways are elevated in males. Management of myocarditis follows heart failure guidelines and there are currently no disease-specific therapies. Research on standard heart failure medications reveal important sex differences. Overall, many advances in our understanding of the effect of biologic sex on myocarditis and DCM have occurred over the past decade, but many gaps in our understanding remain. A better understanding of sex and gender effects are needed to develop disease-targeted and individualized medicine approaches in the future.

[Pericardial and myocardial involvement after SARS-CoV-2 infection: a cross-sectional descriptive study in healthcare workers]

Introduction and objectives

The cardiac sequelae of SARS-CoV-2 infection are still poorly documented. We conducted a cross-sectional study in healthcare workers to report evidence of pericardial and myocardial involvement after SARS-CoV-2 infection.

Methods

We studied 139 healthcare workers with confirmed past SARS-CoV-2 infection. Participants underwent clinical assessment, electrocardiography, and laboratory tests, including immune cell profiling and cardiac magnetic resonance (CMR). Clinically suspected pericarditis was diagnosed when classic criteria were present and clinically suspected myocarditis was based on the combination of at least 2 CMR criteria.

Results

Median age was 52 (41-57) years, 71.9% were women, and 16.5% were previously hospitalized for COVID-19 pneumonia. On examination (10.4 [9.3-11.0] weeks after infection-like symptoms), participants showed hemodynamic stability. Chest pain, dyspnea or palpitations were present in 41.7% participants, electrocardiographic abnormalities in 49.6%, NT-proBNP elevation in 7.9%, troponin in 0.7%, and CMR abnormalities in 60.4%. A total of 30.9% participants met criteria for either pericarditis and/or myocarditis: isolated pericarditis was diagnosed in 5.8%, myopericarditis in 7.9%, and isolated myocarditis in 17.3%. Most participants (73.2%) showed altered immune cell counts in blood, particularly decreased eosinophil (27.3%; P < .001) and increased cytotoxic T cell numbers (17.3%; P < .001). Clinically suspected pericarditis was associated (P < .005) with particularly elevated cytotoxic T cells and decreased eosinophil counts, while participants diagnosed with clinically suspected myopericarditis or myocarditis had lower (P < .05) neutrophil counts, natural killer-cells, and plasma cells.

Conclusions

Pericardial and myocardial involvement with clinical stability are frequent after SARS-CoV-2 infection and are associated with specific immune cell profiles.Full English text available from:www.revespcardiol.org/en.

Pericardial and myocardial involvement after SARS-CoV-2 infection: a cross-sectional descriptive study in healthcare workers

INTRODUCTION AND OBJECTIVES

The cardiac sequelae of SARS-CoV-2 infection are still poorly documented. We conducted a cross-sectional study in healthcare workers to report evidence of pericardial and myocardial involvement after SARS-CoV-2 infection.

METHODS

We studied 139 healthcare workers with confirmed past SARS-CoV-2 infection. Participants underwent clinical assessment, electrocardiography, and laboratory tests, including immune cell profiling and cardiac magnetic resonance (CMR). Clinically suspected pericarditis was diagnosed when classic criteria were present and clinically suspected myocarditis was based on the combination of at least 2 CMR criteria.

RESULTS

Median age was 52 (41-57) years, 71.9% were women, and 16.5% were previously hospitalized for COVID-19 pneumonia. On examination (10.4 [9.3-11.0] weeks after infection-like symptoms), participants showed hemodynamic stability. Chest pain, dyspnea or palpitations were present in 41.7% participants, electrocardiographic abnormalities in 49.6%, NT-proBNP elevation in 7.9%, troponin in 0.7%, and CMR abnormalities in 60.4%. A total of 30.9% participants met criteria for either pericarditis and/or myocarditis: isolated pericarditis was diagnosed in 5.8%, myopericarditis in 7.9%, and isolated myocarditis in 17.3%. Most participants (73.2%) showed altered immune cell counts in blood, particularly decreased eosinophil (27.3%; P<.001) and increased cytotoxic T cell numbers (17.3%; P <.001). Clinically suspected pericarditis was associated (P <.005) with particularly elevated cytotoxic T cells and decreased eosinophil counts, while participants diagnosed with clinically suspected myopericarditis or myocarditis had lower (P <.05) neutrophil counts, natural killer-cells, and plasma cells.

CONCLUSIONS

Pericardial and myocardial involvement with clinical stability are frequent after SARS-CoV-2 infection and are associated with specific immune cell profiles.

Case Series of Myocarditis Following mRNA COVID Vaccine Compared to Pediatric Multisystem Inflammatory Syndrome: Multicenter Retrospective Study

Introduction: Since the development of COVID-19 vaccines, more than 4.8 billion people have been immunized worldwide. Soon after vaccinations were initiated, reports on cases of myocarditis following the second vaccine dose emerged. This study aimed to report our experience with adolescent and young adults who developed post-COVID-19 vaccine myocarditis and to compare these patients to a cohort of patients who acquired pediatric inflammatory multisystem syndrome (PIMS/PIMS-TS) post-COVID-19 infection. Methods: We collected reported cases of patients who developed myocarditis following COVID-19 vaccination (Pfizer mRNA BNT162b2) from all pediatric rheumatology centers in Israel and compared them to a cohort of patients with PIMS. Results: Nine patients with post-vaccination myocarditis were identified and compared to 78 patients diagnosed with PIMS. All patients with post-vaccination myocarditis were males who developed symptoms following their second dose of the vaccine. Patients with post-vaccination myocarditis had a shorter duration of stay in the hospital (mean 4.4 ± 1.9 vs. 8.7 ± 4.7 days) and less myocardial dysfunction (11.1% vs. 61.5%), and all had excellent outcomes as compared to the chronic changes among 9.2% of the patients with PIMS. Conclusion: The clinical course of vaccine-associated myocarditis appears favorable, with resolution of the symptoms in all the patients in our cohort.

Prevalence of myocarditis, genetic cardiomyopathies and their combinations among patients of the Cardiology Hospital of the V.N. Vinogradov Faculty Therapeutic Clinic of the Sechenov University

Aim. To establish the prevalence of myocarditis and primary (genetic) cardiomyopathies (CMP) among patients in a cardiology hospital.

Material and methods. Medical records of 671 patients of the cardiology department were analyzed. The diagnosis at admission and at discharge was recorded. The diagnoses were divided into 7 following categories: hypertension, coronary artery disease, heart disease, idiopathic arrhythmias, cardiomyopathy, myocarditis and others. Types of myocarditis and cardiomyopathy, the presence of arrhythmias and heart failure were also recorded.

Results. Myocarditis was diagnosed in 194 (28,9%) patients, cardiomyopathy — in 76 (11,3%) patients, combination of cardiomyopathy and myocarditis — in 26 (3,9%) patients. Myocarditis with the development of arrhythmia and heart dilatation prevailed as follows: 47,4 and 41,2%, respectively. The most numerous CMPs were left ventricular noncompaction (n=30), non-inflammatory dilated CMP (n=13), hypertrophic CMP (n=10) and arrhythmogenic CMP of the right ventricle (n=9). In the group with idiopathic arrhythmias, 64,3% of patients were diagnosed with myocarditis, and 19,4% — with cardiomyopathy.

Conclusion. The prevalence of non-coronary myocardial diseases among patients in a cardiology hospital is high and amounts to 40,2%. The presence of arrhythmias, heart failure or dilated cardiomyopathy may be a manifestation of non-coronary myocardial diseases, and requires a comprehensive examination aimed, in particular, at ruling out or verifying the diagnosis of myocarditis.

Sex-Related Differences in Genetic Cardiomyopathies

Cardiomyopathies are a heterogeneous collection of diseases that have in common primary functional and structural abnormalities of the heart muscle, often genetically determined. The most effective categorization of cardiomyopathies is based on the presenting phenotype, with hypertrophic, dilated, arrhythmogenic, and restrictive cardiomyopathy as the prototypes. Sex modulates the prevalence, morpho-functional manifestations and clinical course of cardiomyopathies. Aspects as diverse as ion channel expression and left ventricular remodeling differ in male and female patients with myocardial disease, although the reasons for this are poorly understood. Moreover, clinical differences may also result from complex societal/environmental discrepancies between sexes that may disadvantage women. This review provides a state-of-the-art appraisal of the influence of sex on cardiomyopathies, highlighting the many gaps in knowledge and open research questions.

Increased Interleukin 18-Dependent Immune Responses Are Associated With Myopericarditis After COVID-19 mRNA Vaccination

Myocarditis and myopericarditis may occur after COVID-19 vaccination with an incidence of two to twenty cases per 100,000 individuals, but underlying mechanisms related to disease onset and progression remain unclear. Here, we report a case of myopericarditis following the first dose of the mRNA-1273 COVID-19 vaccine in a young man who had a history of mild COVID-19 three months before vaccination. The patient presented with chest pain, elevated troponin I level, and electrocardiogram abnormality. His endomyocardial biopsy revealed diffuse CD68⁺ cell infiltration. We characterized the immune profile of the patient using multiplex cytokine assay and flow cytometry analysis. Sex-matched vaccinated individuals and healthy individuals were used as controls. IL-18 and IL-27, Th1-type cytokines, were highly increased in the patient with COVID-19 vaccine-related myopericarditis compared with vaccinated controls who experienced no cardiac complications. In the patient, circulating NK cells and T cells showed an activated phenotype and mRNA profile, and monocytes expressed increased levels of IL-18 and its upstream NLRP3 inflammasome. We found that recombinant IL-18 administration into mice caused mild cardiac dysfunction and activation of NK cells and T cells in the hearts, similar to the findings in the patient with myopericarditis after COVID-19 mRNA vaccination. Collectively, myopericarditis following COVID-19 mRNA vaccination may be associated with increased IL-18-mediated immune responses and cardiotoxicity.

Biological Sex and Its Impact on Clinical Characteristics in Patients Presenting with Myocarditis

INTRODUCTION

Biological sex has a paramount influence on the pathophysiology of diseases, and thus on clinical presentation. In this study, we provide a comprehensive analysis of sex-specific differences in patients with myocarditis.

MATERIALS AND METHODS

Patients with myocarditis who were admitted to our study center in the time-period of 2009-2019 were retrospectively enrolled in this study. Clinical data, laboratory parameters, and measurements from transthoracic echocardiography were extracted from hospital records. Follow-up was acquired for 2 years after admission.

RESULTS

Two hundred twenty-four patients with myocarditis were enrolled in this study. Of these, 78% were men and 22% women. Female patients were older (median 50 years vs. 35 years, p < 0.0001), had a higher prevalence of respiratory tract infections, and had less frequently ST-segment elevations on electrocardiogram (ECG) (28% vs. 59%, p = 0.003). Furthermore, C-reactive protein was lower in women (median 0.60 mg/dL vs. 3.90 mg/dL, p < 0.0001), but showed a less pronounced decrease within 3 days when compared to men (fold-change 1.00 vs. 0.80, p = 0.002). Cardiac magnetic resonance imaging was conducted less often in women, whereas time to coronary angiography was significantly longer. We found no difference in left ventricular systolic function or all-cause-mortality between the 2 sexes.

CONCLUSION

We observed sex-specific differences in laboratory parameters, abnormalities on ECG, and diagnostic procedures conducted in patients with myocarditis. Understanding these differences, both at the cellular level and in regard to the clinical presentation of patients, could be helpful in the diagnosis and treatment of this disease, and could further expand our understanding of its pathophysiology.

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.

Circular RNA circACSL1 aggravated myocardial inflammation and myocardial injury by sponging miR-8055 and regulating MAPK14 expression

Myocarditis (MC) is a common, potentially life-threatening inflammatory disease of the myocardium. A growing body of evidence has shown that mitogen-activated protein kinase 14 (MAPK14) participates in the pathogenesis of MC. However, the upstream regulators of MAPK14 remain enigmatic. Circular RNAs (circRNAs) have been identified to play vital roles in the pathophysiology of cardiovascular diseases. Nevertheless, the clinical significance, biological function, and regulatory mechanisms of circRNAs in MC remain poorly understood. In this study, we determined a novel circRNA, circACSL1 (ID: hsa_circ_0071542), which was significantly upregulated in the acute phase of MC, and its dynamic change in expression was related to the progression of MC. We used lipopolysaccharide (LPS) to induce the inflammatory responses in the human cardiomyocytes (HCM) line for in vitro and in cellulo experiments. The pro-inflammatory factors (IL-1β, IL-6, and TNF-α), myocardial injury markers (cTnT, CKMB, and BNP), cell viability, and cell apoptosis were measured to evaluate the extent of myocardial inflammation and myocardial injury level. Functional experiments, including gain-of-function and loss-of-function, were then performed to investigate the pro-inflammatory roles of circACSL1. The results revealed that circACSL1 could aggravate inflammation, myocardial injury, and apoptosis in HCM. Mechanistically, circACSL1 acted as a sponge for miR-8055-binding sites to regulate the downstream target MAPK14 expression. Furthermore, overexpression of miR-8055 rescued the pro-inflammatory effects of circACSL1 on HCM, and the upregulation of MAPK14 induced by circACSL1 was attenuated by miR-8055 overexpression. Knockdown of circACSL1 or overexpression of miR-8055 reduced myocardial inflammation and myocardial injury level and these effects were rescued by overexpression of MAPK14. In summary, our study demonstrated that circACSL1 could aggravate myocardial inflammation and myocardial injury through competitive absorption of miR-8055, thereby upregulating MAPK14 expression. Moreover, circACSL1 may represent a potential novel biomarker for the precise diagnosis of MC and offer a promising therapeutic target for MC treatment.

Incidence and outcomes of hospital treated acute myocarditis from 2003 to 2015 in Spain

BACKGROUND

There are no data on population-based epidemiological changes in acute myocarditis in Europe. Our aim was to evaluate temporal trends in incidence, clinical features and outcomes of hospital treated acute myocarditis (AM) in Spain from 2003 to 2015.

METHODS

We conducted a retrospective longitudinal study using information of all hospital discharges of the Spanish National Health System. All episodes with a discharge diagnosis of AM from 1 January 2003 to 31 December 2015 were included. The risk-standardized in-hospital mortality ratio (RSMR) was calculated using a multilevel risk-adjustment model developed by the Medicare and Medicaid Services. Temporal trends for in-hospital mortality were modelled using Poisson regression analysis.

RESULTS

A total of 11 147 episodes of AM were analysed, most of them idiopathic (94.7%). The rate of AM discharges increased along the period, from 13 to 30/million inhabitants/year (2003-2015), and this increase was statistically significant when weighted by age and sex (incidence rate ratio, IRR 1.06, 95% CI 1.04-1.08, P = .001). In-hospital crude mortality rate was 3.1%, diminishing significantly along 2003-2015 (IRR 0.95, 95% CI 0.92-0.99, P = .02). RSMR also significantly diminished along the period (IRR 0.95, 95% CI 0.92-0.99, P = .01). Renal failure (OR 7.03, 5.38-9.18, P = .001), liver disease (OR 4.61, 2.59-8.21, P = .001), pneumonia (OR 4.13, 2.75-6.20, P = .001) and heart failure (OR 1.91, 95% CI 1.47-2.47, P = .001) were the strongest independent factors associated with in-hospital mortality.

CONCLUSIONS

Acute myocarditis is an uncommon entity, although hospital discharges have increased in Spain along the study period. Most of AM were idiopathic. Adjusted mortality was low and seemed to decrease from 2003 to 2015, suggesting an improvement in AM management.

Characterization and long-term outcomes of patients with myocarditis: a retrospective observational study

Introduction

There is limited data on the long-term follow-up of patients with myocarditis.

Aim

To investigate the long-term follow-up of patients with myocarditis.

Material and methods

We performed a retrospective observational analysis on the clinical long-term outcomes of patients with myocarditis over a 10-year period. The primary outcome was mortality. We identified risk factors for mortality and adverse clinical outcomes. We also compared the characteristics and outcomes of patients presenting with fulminant myocarditis to those presenting with non-fulminant myocarditis.

Results

Between May 2004 and December 2014, 203 patients with myocarditis or perimyocarditis were admitted to our center. Most patients were male (87.7%) with a median age at presentation of 33 years (interquartile range: 25.4–38.9). The median follow-up period was 56.9 months (interquartile range 25.3–87.3 months), during which the overall mortality was 4.4% (9 patients). Fifteen patients presented with fulminant myocarditis. After multivariable analysis, older age (HR = 1.11, 95% CI: 1.05–1.16, p < 0.001) and a poorer New York Heart Association (NYHA) function class (HR = 4.6, 95% CI: 1.18–18, p = 0.028) were found to be independently associated with a higher risk of mortality, whereas higher albumin levels at presentation (HR = 0.2, 95% CI: 0.07–0.56, p = 0.002) were associated with decreased mortality. The group presenting with fulminant myocarditis had a more severe course of disease and a higher in-hospital mortality (13.3% vs. 0%, p = 0.005).

Conclusions

The overall prognosis of patients with myocarditis is good – in terms of both survival and recovery without residual left ventricular dysfunction.

HEllenic Registry on Myocarditis SyndromES on behalf of Hellenic Heart Failure Association: The HERMES-HF Registry

AIMS

Despite the existence of many studies, there are still limited data about the characteristics of myocarditis in Greece. This led to the creation of the Greek Myocarditis Registry aiming to document the different symptoms and treatment of myocarditis, assess possible prognostic factors, and find similarities and differences to what is already published in literature. This paper is a preliminary descriptive analysis of this Registry.

METHODS AND RESULTS

We analysed data for the hospitalization period of all patients included in the Registry from December 2015 until November 2017. Statistics are reported as frequency (%) or median and inter-quartile range (IQR) as appropriate. In total, 146 patients were included; 83.3% of the patients reported an infection during the last 3 months. The most common symptom, regardless of the underlying infection, was chest pain (82.2%) followed by dyspnoea (18.5%), while the most common finding in clinical examination was tachycardia (26.7%). Presentation was more frequent in the winter months. ECG findings were not specific, with the repolarization abnormalities being the most frequent (60.3%). Atrial fibrillation was observed in two patients, both of whom presented with a reduced ventricular systolic function. Left ventricular ejection fraction changed significantly during the hospitalization [55% (IQR: 50-60%) on admission vs. 60% (IQR: 55-60%) on discharge, P = 0.0026]. Cardiac magnetic resonance was performed in 88 patients (61%), revealing mainly subepicardial and midcardial involvement of the lateral wall. Late gadolinium enhancement was present in all patients, while oedema was found in 39 of them. Only 11 patients underwent endomyocardial biopsy. Discharge medication consisted mainly of beta-blockers (71.9%) and angiotensin-converting enzyme inhibitors (41.8%), while 39.7% of the patients were prescribed both.

CONCLUSIONS

This preliminary analysis describes the typical presentation of myocarditis patients in Greece. It is a first step in developing a better prognostic model for the course of the disease, which will be completed after the incorporation of the patients' follow-up data.

Immune Checkpoint Inhibitor Cardiotoxicity: Understanding Basic Mechanisms and Clinical Characteristics and Finding a Cure

Immune checkpoint inhibitors (ICIs) attenuate mechanisms of self-tolerance in the immune system, enabling T cell responses to cancerous tissues and revolutionizing care for cancer patients. However, by loweringbarriers against self-reactivity, ICIs often result in varying degrees of autoimmunity. Cardiovascular complications, particularly myocarditis but also arrhythmias, pericarditis, and vasculitis, have emerged as significant complications associated with ICIs. In this review, we examine the clinical aspects and basic science principles that underlie ICI-associated myocarditis and other cardiovascular toxicities. In addition, we discuss current therapeutic approaches. We believe a better mechanistic understanding of ICI-associated toxicities can lead to improved patient outcomes by reducing treatment-related morbidity.

Sex-Based Differences in Characteristics and In-Hospital Outcomes among Patients With Diagnosed Acute Myocarditis

Data are scarce regarding sex differences among patients with acute myocarditis (AM). Our aim was to define the sex differences in clinical characteristics as well as in-hospital outcomes in a cohort of consecutive patients hospitalized due to AM. We analyzed data of 322 consecutive patients from January 2005 to December 2017 who were hospitalized with the diagnosis of AM. Eighty-four percent (N = 272) of the patients were males. When compared to females, male patients were younger (36 ± 14 vs 45 ± 17 years, p <0.001), more likely to present with ST segment elevation (75% vs 44%. p <0.001) as well as PR depression upon ECG, and have higher admission troponin levels (7.6 ± 11 vs 2.3 ± 4 µg/L, p <0.001). Moreover, males were more likely to have late gadolinium enhancement upon cardiac magnetic resonance. While male patients were more likely to have ventricular arrhythmias during hospitalization (7% vs 0%, p = 0.05), there were no differences in the incidence of in-hospital mortality or the need for escalation therapy during hospitalization between both groups. There were no episodes of mortality upon all patients among a follow-up of 1 year. In conclusion, male patients, which constitute the majority of patients admitted with AM were younger, more likely to present with ST elevation, had higher troponin levels at admission, and had a higher rate of ventricular arrhythmias compared to females. There were no differences in post-discharge mortality rates between males and females.

Autoimmunity in Acute Myocarditis: How Immunopathogenesis Steers New Directions for Diagnosis and Treatment

PURPOSE OF REVIEW

Over the last decade, myocarditis has been increasingly recognized as common cause of sudden cardiac death in young adults and heart failure overall. The purpose of this review is to discuss hypothesis of development of non-infectious myocarditis, to provide a description of the immunopathogenesis and the most common mechanisms of autoimmunity in myocarditis, and to provide an update on therapeutic options.

RECENT FINDINGS

A new entity of myocarditis is immune checkpoint inhibitor (ICI) induced myocarditis. ICIs are used in advanced cancer to "disinhibit" the immune system and make it more aggressive in fighting cancer. This novel drug class has doubled life expectancy in metastatic melanoma and significantly increased progression free survival in advanced non-small-cell lung cancer, but comes with a risk of autoimmune diseases such as myocarditis resulting from an overly aggressive immune system. Myocarditis is an inflammatory disease of the heart with major public health impact. Thorough understanding of its immunopathogenesis is crucial for accurate diagnosis and effective treatment.