Management of Acute Myocarditis and Chronic Inflammatory Cardiomyopathy: An Expert Consensus Document

The role of echocardiography in sports cardiology: An expert opinion statement of the Italian Society of Sports Cardiology (SIC sport)

Transthoracic echocardiography (TTE) is routinely required during pre-participation screening in the presence of symptoms, family history of sudden cardiac death or cardiomyopathies <40-year-old, murmurs, abnormal ECG findings or in the follow-up of athletes with a history of cardiovascular disease (CVD). TTE is a cost-effective first-line imaging modality to evaluate the cardiac remodeling due to long-term, intense training, previously known as the athlete's heart, and to rule out the presence of conditions at risk of sudden cardiac death, including cardiomyopathies, coronary artery anomalies, congenital, aortic and heart valve diseases. Moreover, TTE is useful for distinguishing physiological cardiac adaptations during intense exercise from pathological behavior due to an underlying CVD. In this expert opinion statement endorsed by the Italian Society of Sports Cardiology, we discussed common clinical scenarios where a TTE is required and conditions falling in the grey zone between the athlete's heart and underlying cardiomyopathies or other CVD. In addition, we propose a minimum dataset that should be included in the report for the most common indications of TTE in sports cardiology clinical practice.

Fatal ventricular arrhythmias in myocarditis: A review of current indications for defibrillator devices

Historically, patients with myocarditis were considered for implantable cardioverter defibrillator (ICD) utilization only in the chronic phase of the disease following the development of persistent cardiomyopathy refractory to medical therapy or occurrence of a major ventricular arrhythmic event. However, recent literature has indicated that ventricular arrhythmias are frequently reported even in the acute phase of the disease, challenging the long-standing perception that this disease process was largely reversible. Given this changing environment of information, the latest US and European guidelines were recently updated in 2022 to now consider ICD implantation during the acute phase which has significantly increased the number of individuals eligible for these devices. Additionally, several studies with small subgroups of patients have demonstrated a possible benefit of wearable cardioverter defibrillators (WCDs) in this patient demographic. Assuming that larger studies confirm their utility, it is possible that WCDs can assist in detection of ventricular arrhythmias and selection of high-risk candidates for ICD implantation, while providing temporary protection for a small percentage of patients before the development of a major arrhythmic event. This review ultimately serves as a comprehensive review of the most recent guidelines for defibrillator use in acute and chronic myocarditis. OPINION STATEMENT: The latest US and European guidelines support ICD use for myocarditis patients following the development of persistent cardiomyopathy refractory to medical therapy or occurrence of a major ventricular arrhythmic event. Previously, patients in the acute phase were excluded from ICD utilization even after experiencing malignant ventricular tachycardia or ventricular fibrillation due to the long-standing perception that this disease process was largely reversible. However, recent literature has indicated that ventricular arrhythmias are frequently reported even in the acute phase of the disease. Additionally, we found that the myocardial damage that is inflicted persists many years after the initial episode. Given this changing environment of information, guidelines were recently updated in 2022 to now consider ICD implantation during the acute phase which has significantly increased the number of individuals eligible for these devices. We support possible ICD utilization for secondary prevention during the acute phase of myocarditis given the elevated risk of arrhythmia recurrence and the fact that any ventricular arrhythmia can induce sudden cardiac death. Future prospective studies are needed to assess which patients may benefit most from early ICD implantation. WCDs have improved survival in patient populations at high-risk for sudden cardiac death who are not candidates for ICD implantation. After analyzing several recent studies with small subgroups of patients, WCDs appear to demonstrate similar efficacy for myocarditis patients as well. Assuming that larger studies confirm their utility, we believe that WCDs can assist in detection of ventricular arrhythmias and selection of high-risk candidates for ICD implantation. Furthermore, WCDs have the additional benefit of acting as primary prevention by providing temporary protection for a small percentage of myocarditis patients before they develop a major arrhythmic event.

When, Why and How to Re-challenge Clozapine in Schizophrenia Following Myocarditis

Clozapine-induced myocarditis (CIM) is among the most important adverse events limiting the use of clozapine as the most effective treatment for schizophrenia. CIM necessitates the immediate termination of clozapine, often resulting in its permanent discontinuation with considerable detrimental effects on patients' psychopathology and long-term outcome. Consequently, a clozapine re-challenge after CIM is increasingly regarded as a viable alternative, with published reports indicating a success rate of approximately 60%. However, published cases of re-challenges after CIM remain limited. Here, we provide a narrative review of the current state of research regarding the epidemiology, pathophysiology, risk factors, diagnosis and clinical management of CIM as well as a synthesis of current recommendations for re-challenging patients after CIM. This includes a step-by-step guide for this crucial procedure based on the current evidence regarding the pathophysiology and risk factors for CIM. Slow dose titration regimes and addressing risk factors including concomitant valproate and olanzapine are crucial both to prevent CIM and to ensure a safe and successful re-challenge. Furthermore, we discuss the utility of C-reactive protein, troponin, N-terminal-pro hormone and brain natriuretic peptide, therapeutic drug-monitoring and cardiac magnetic resonance imaging for CIM screening and diagnosis as well as for post-CIM re-challenges.

The natural history of CVB3 myocarditis in C57BL/6J mice: an extended in-depth characterization

BACKGROUND AND AIMS

Viral infections are the leading cause of myocarditis. Besides acute cardiac complications, late-stage sequelae such as myocardial fibrosis may develop, importantly impacting the prognosis. Coxsackievirus B3 (CVB)-induced myocarditis in mice is the most commonly used translational model to study viral myocarditis and has provided the majority of our current understanding of the disease pathophysiology. Nevertheless, the late stages of disease, encompassing fibrogenesis and arrhythmogenesis, have been underappreciated in viral myocarditis research to date. The present study investigated the natural history of CVB-induced myocarditis in C57BL/6J mice, expanding the focus beyond the acute phase of disease. In addition, we studied the impact of sex and inoculation dose on the disease course.

METHODS AND RESULTS

C57BL/6J mice (12 weeks old; n=154) received a single intraperitoneal injection with CVB to induce viral myocarditis, or vehicle (PBS) as control. Male mice (n=92) were injected with 5 × 105 (regular dose) (RD) or 5 × 106 (high dose) (HD) plaque-forming units of CVB, whereas female mice received the RD only. Animals were sacrificed 1, 2, 4, 8, and 11 weeks after CVB or PBS injection. Virally inoculated mice developed viral disease with a temporary decline in general condition and weight loss, which was less pronounced in female animals (P<.001). In male CVB mice, premature mortality occurred between days 8 and 23 after inoculation (RD: 21%, HD: 20%), whereas all female animals survived. Over the course of disease, cardiac inflammation progressively subsided, with faster resolution in female mice. There were no substantial group differences in the composition of the inflammatory cell infiltrates: predominance of cytotoxic T cells at day 7 and 14, and a switch from arginase1-reactive macrophages to iNOS-reactive macrophages from day 7 to 14 were the main findings. There was concomitant development and maturation of different patterns of myocardial fibrosis, with enhanced fibrogenesis in male mice. Virus was almost completely cleared from the heart by day 14. Serum biomarkers of cardiac damage and cardiac expression of remodeling genes were temporarily elevated during the acute phase of disease. Cardiac CTGF gene upregulation was less prolonged in female CVB animals. In vivo electrophysiology studies at weeks 8 and 11 demonstrated that under baseline conditions (i.e. in the absence of proarrhythmogenic drugs), ventricular arrhythmias could only be induced in CVB animals. The cumulative arrhythmia burden throughout the entire stimulation protocol was not significantly different between CVB and control groups.

CONCLUSION

CVB inoculation in C57BL/6J mice represents a model of acute self-limiting viral myocarditis, with progression to different patterns of myocardial fibrosis. Sex, but not inoculation dose, seems to modulate the course of disease.

A challenging case of eosinophilic myocarditis leading to heart failure and transplantation

The large spectrum of etiologies, severities, and histologic appearances of eosinophilic myocarditis (EoM) poses challenges to its diagnosis and management. Endomyocardial biopsy is the current gold standard for diagnosis. However, cardiovascular magnetic resonance imaging is becoming more frequently used to diagnose acute myocarditis because of enhanced sensitivity when compared to histopathologic examination, and its less invasive nature. We report a complicated case of EoM in a male in his mid-thirties that led to fulminant cardiogenic shock that required immunosuppressive therapy on day 5 of admission and implantation of a left ventricular assist device (LVAD) on day 30. EoM was diagnosed on histopathologic examination of the resected fragment of the left ventricular myocardium. Nine months after the initial presentation, the patient ultimately required heart transplantation. The explanted heart showed minimal residual interstitial inflammation with evidence of mildly active intimal arteritis and patchy areas of interstitial fibrosis. In this report, we describe our patient's clinical features and correlate them with imaging and histopathologic findings to illustrate the difficulty in diagnosing EoM, particularly in this complicated patient that ultimately required heart transplantation. The diagnosis can be challenging due to the variable histopathologic features, clinical presentation, and utilization of therapeutic medications and devices.

Endosomal Toll-Like Receptors intermediate negative impacts of viral diseases, autoimmune diseases, and inflammatory immune responses on the cardiovascular system

INTRODUCTION

Cardiovascular disease (CVD) is the leading cause of morbidity globally, with chronic inflammation as a key modifiable risk factor. Toll-like receptors (TLRs), pivotal components of the innate immune system, including TLR-3, -7, -8, and -9 within endosomes, trigger intracellular cascades, leading to inflammatory cytokine production by various cell types, contributing to systemic inflammation and atherosclerosis. Recent research highlights the role of endosomal TLRs in recognizing self-derived nucleic acids during sterile inflammation, implicated in autoimmune conditions like myocarditis.

AREAS COVERED

This review explores the impact of endosomal TLRs on viral infections, autoimmunity, and inflammatory responses, shedding light on their intricate involvement in cardiovascular health and disease by examining literature on TLR-mediated mechanisms and their roles in CVD pathophysiology.

EXPERT OPINION

Removal of endosomal TLRs mitigates myocardial damage and immune reactions, applicable in myocardial injury. Targeting TLRs with agonists enhances innate immunity against fatal viruses, lowering viral loads and mortality. Prophylactic TLR agonist administration upregulates TLRs, protecting against fatal viruses and improving survival. TLRs play a complex role in CVDs like atherosclerosis and myocarditis, with therapeutic potential in modulating TLR reactions for cardiovascular health.

A novel predictive score model for successful weaning from mechanical circulatory support in patients with cardiogenic shock

BACKGROUND

Clinical evidence regarding predictors of successful weaning from mechanical circulatory support (MCS) is lacking. This study aimed to create a simple risk score to predict successful weaning from MCS in patients with cardiogenic shock.

METHODS

This retrospective single-center cohort study included 114 consecutive patients with cardiogenic shock treated with veno-arterial extracorporeal membrane oxygenation or IMPELLA between January 2013 and June 2023. Patients with out-of-hospital cardiac arrest were excluded. The primary endpoint was successful weaning from MCS defined as successful decannulation without the need for MCS re-implantation and survival to discharge. Multivariable logistic regression with a stepwise variable selection was performed to generate the prediction model. We first developed a general weaning score model, and then created a simple version of the score model using the same variables.

RESULTS

Fifty-five patients were successfully weaned from MCS. The following variables measured during weaning evaluation were selected as the components of the weaning score model: acute myocardial infarction (AMI), mean blood pressure, left ventricular ejection fraction (LVEF), lactate level, and QRS duration. According to the results, we conducted a novel weaning score model to predict successful weaning from MCS: 1.774-2.090×(AMI)+0.062×[mean blood pressure (mmHg)]+0.139×[LVEF (%)]-0.322×[Lactate (mg/dl)]-0.066×[QRS (msec)]. The following variables were selected as the components of the simple version of the weaning score model: AMI, mean blood pressure ≥80 mmHg, lactate <10 mg/dL, QRS duration ≤95 msec, and LVEF >35%.

CONCLUSIONS

We developed a simple model to predict successful weaning from MCS in patients with cardiogenic shock.

Early identification of severe immune checkpoint inhibitor associated myocarditis: From an electrocardiographic perspective

OBJECTIVES

Immune checkpoint inhibitor (ICI)-associated myocarditis, particularly severe ICI-associated myocarditis, has a high mortality rate. However, the predictive value of electrocardiogram (ECG) remains unclear. The present study aimed to evaluate the predictive value of clinical and electrocardiographic parameters for severe myocarditis.

METHODS

Clinical and electrocardiographic data of 73 cancer patients with ICI-associated myocarditis were retrospectively collected. The severity of ICI-associated myocarditis was graded using the NCCN guidelines for managing immunotherapy-related toxicities. Myocarditis grades 1-2 and grades 3-4 were classified as mild and severe myocarditis, respectively. Logistic regression analysis was performed to analyze the predictive value of each parameter in predicting severe myocarditis.

RESULTS

Among the 73 patients with myocarditis, 20 (27.4%) patients had severe myocarditis. Compared with mild myocarditis group, sinus tachycardia (p = 0.001), QRS duration ≥110 ms (p = 0.001), prolonged QTc interval (p < 0.001), and bundle branch block (p = 0.007) at the time of myocarditis were more common in the severe myocarditis group. Logistic regression analysis revealed that sinus tachycardia (p = 0.028) and QTc interval prolongation (p = 0.007) were predictors of severe myocarditis. Whereas the predictive value of other electrocardiographic parameters was weak. Concurrent targeted therapy didn't increase the risk of severe myocarditis. A high NT-proBNP level was associated with severe myocarditis.

CONCLUSIONS

ECG at the onset of myocarditis manifested as sinus tachycardia and prolonged QTc interval predicted a high risk of severe myocarditis. Early detection of ECG abnormalities may faciliate early detection of severe ICI-associated myocarditis.

Diagnosis and treatment of myocarditis and inflammatory cardiomyopathy. Consensus document of the SEC-Working Group on Myocarditis

Myocarditis is defined as myocardial inflammation and its etiology is highly diverse, including infectious agents, drugs, and autoimmune diseases. The clinical presentation also varies widely, extending beyond the classic clinical picture of acute chest pain, and includes cases of cardiomyopathy of unknown cause whose etiology may be inflammatory. Because certain patients may benefit from targeted treatments, the search for the etiology should begin when myocarditis is first suspected. There remain several areas of uncertainty in the diagnosis and treatment of this disease. Consequently, this consensus document aims to provide clear recommendations for its diagnosis and treatment. Hence, a diagnostic algorithm is proposed, specifying when non-invasive diagnosis with cardiac MR is appropriate vs a noninvasive approach with endomyocardial biopsy. In addition, more novel aspects are discussed, such as when to suspect an underlying genetic etiology. The recommendations cover the management of myocarditis and inflammatory cardiomyopathy, both for general complications and specific clinical entities.

Cardiovascular magnetic resonance parametric mapping in the risk stratification of patients affected by chronic myocarditis

OBJECTIVES

Chronic myocardial inflammation is the substrate for arrhythmias and dilated cardiomyopathy onset, causing morbidity and mortality. Cardiovascular magnetic resonance (CMR) is the noninvasive gold standard for myocardial inflammation detection, due to the high sensitivity of the parametric mapping techniques. However, the potential prognostic capabilities of CMR mapping have not been studied in the setting of chronic myocarditis.

METHODS

This is a retrospective study on consecutive patients undergoing CMR with suspicion of chronic myocarditis from September 2017 to November 2021. CMR was acquired according to 2018 Lake Louise Criteria recommendations. The outcome (chronic heart failure, recurrent chronic myocarditic chest pain, ICD/PM implantation, arrhythmias [Lown class ≥ 2]) was collected at follow-up. The extent and degree of native T1, T2, and extracellular volume fraction alterations were used to create multivariate binary logistic regression models for outcome prediction, with or without left ventricle ejection fraction; their AUCs were compared with DeLong test. Differences between other parameters were assessed using Chi-square test, Fisher's exact test, or Mann-Whitney U-test.

RESULTS

The population included 88 patients (age 43 [32-52] yo), mostly male (53/88, 60%). After a median follow-up of 21 (17-34) months, 31/88 (35%) patients experienced the outcome. The model based on the extension of mapping alterations and LV dysfunction reached a good predictability (AUC 0.71). The model based on the intensity of mapping alterations and LV dysfunction had a very good performance (AUC 0.80).

CONCLUSION

The quantitative analysis of CMR mapping parameters indicative of myocardial damage severity may improve risk stratification in patients with chronic myocarditis.

CLINICAL RELEVANCE STATEMENT

The intensity of myocardial damage, assessed as the degree of native T1, T2, and ECV alteration, together with left ventricle dysfunction, improved patient risk stratification. Further prospective studies will be necessary for validation before clinical application.

KEY POINTS

Risk stratification of patients affected by chronic myocarditis is an unmet clinical need. Cardiovascular MRI (CMR) can role in risk stratification thanks to its multiparametric capabilities of tissue characterization. A model based on CMR parametric mapping and left ventricle ejection fraction can predict arrhythmia, heart failure, and recurrent symptoms.

Novel tracers to assess myocardial inflammation with radionuclide imaging

Myocardial inflammation plays a central role in the pathophysiology of various cardiac diseases. While FDG-PET is currently the primary method for molecular imaging of myocardial inflammation, its effectiveness is hindered by physiological myocardial uptake as well as its propensity for uptake by multiple disease-specific mechanisms. Novel radiotracers targeting diverse inflammatory immune cells and molecular pathways may provide unique insight through the visualization of underlying mechanisms central to the pathogenesis of inflammatory cardiac diseases, offering opportunities for increased understanding of immunocardiology. Moreover, the potentially enhanced specificity may lead to better quantification of disease activity, aiding in the guidance and monitoring of immunomodulatory therapy. This review aims to provide an update on advancements in non-FDG radiotracers for imaging myocardial inflammatory diseases, with a focus on cardiac sarcoidosis, myocarditis, and acute myocardial infarction.

Treatment time limit for successful weaning from veno-arterial extracorporeal membrane oxygenation in cardiogenic shock

AIMS

Knowing the upper time limit for successful weaning from temporary mechanical circulatory support in cardiogenic shock will help with decision-making regarding advanced heart failure (HF) therapy or considering withdrawal of care. The aim of this study was to investigate the association between the support duration and successful weaning from veno-arterial extracorporeal membrane oxygenation (VA-ECMO) in patients with cardiogenic shock.

METHODS AND RESULTS

A retrospective single-centre cohort study was conducted between January 2013 and June 2023. It included 100 consecutive patients with cardiogenic shock who were treated with VA-ECMO. Patients with out-of-hospital cardiac arrest were excluded. The primary outcome was successful weaning from VA-ECMO (i.e., VA-ECMO decannulation and survival to discharge). The association between the length of support duration and the weaning success rate was analysed. Patients were divided into three groups according to ECMO support duration: Group A (≤7 days), Group B (8-14 days), and Group C (≥15 days). Multivariable logistic regression analysis was used to evaluate the impact of the length of support duration on successful weaning of VA-ECMO. The median age was 67 years, and 73% of study participants were male. The underlying aetiologies of cardiogenic shock were as follows: acute myocardial infarction, 50; fulminant myocarditis, 19; cardiomyopathy, 15; valvular heart disease, 8; and other, 8. Seventy-five patients (75%) were attempted to wean VA-ECMO, and 67 moved on to decannulation. In total, 43 (43%) patients were successfully weaned from VA-ECMO. The median length of ECMO support duration was 8 [3-15] days. Compared with those who underwent successful ECMO decannulation, those who did not had a significantly longer support duration of VA-ECMO (5 [3-9] days vs. 12 [3-22] days, P = 0.004). The weaning success rate was significantly higher in patients with short support duration; 58% (29/50), 40% (10/25), 16% (4/25) in Groups A, B, and C, respectively (P = 0.002). Overall, none of the patients supported for over 24 days (0/11) were successfully weaned from VA-ECMO. On multivariable logistic regression analysis, the length of support duration was independently associated with successful weaning after adjusting for age, sex, underlying aetiology, and left ventricular ejection fraction (odds ratio, 0.813 [per 3 days]; 95% confidence interval, 0.679-0.914; P = 0.025).

CONCLUSIONS

Long support duration of VA-ECMO was significantly associated with a low rate of successful weaning in patients with cardiogenic shock. Patients who require VA-ECMO for over 1 week should start considering advanced HF therapy or withdrawal of care.

Clinical Characteristics and Mechanisms of Acute Myocarditis

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT05335928.

Mechanisms of myocardial reverse remodelling and its clinical significance: A scientific statement of the ESC Working Group on Myocardial Function

Cardiovascular disease (CVD) is the leading cause of morbimortality in Europe and worldwide. CVD imposes a heterogeneous spectrum of cardiac remodelling, depending on the insult nature, that is, pressure or volume overload, ischaemia, arrhythmias, infection, pathogenic gene variant, or cardiotoxicity. Moreover, the progression of CVD-induced remodelling is influenced by sex, age, genetic background and comorbidities, impacting patients' outcomes and prognosis. Cardiac reverse remodelling (RR) is defined as any normative improvement in cardiac geometry and function, driven by therapeutic interventions and rarely occurring spontaneously. While RR is the outcome desired for most CVD treatments, they often only slow/halt its progression or modify risk factors, calling for novel and more timely RR approaches. Interventions triggering RR depend on the myocardial insult and include drugs (renin-angiotensin-aldosterone system inhibitors, beta-blockers, diuretics and sodium-glucose cotransporter 2 inhibitors), devices (cardiac resynchronization therapy, ventricular assist devices), surgeries (valve replacement, coronary artery bypass graft), or physiological responses (deconditioning, postpartum). Subsequently, cardiac RR is inferred from the degree of normalization of left ventricular mass, ejection fraction and end-diastolic/end-systolic volumes, whose extent often correlates with patients' prognosis. However, strategies aimed at achieving sustained cardiac improvement, predictive models assessing the extent of RR, or even clinical endpoints that allow for distinguishing complete from incomplete RR or adverse remodelling objectively, remain limited and controversial. This scientific statement aims to define RR, clarify its underlying (patho)physiologic mechanisms and address (non)pharmacological options and promising strategies to promote RR, focusing on the left heart. We highlight the predictors of the extent of RR and review the prognostic significance/impact of incomplete RR/adverse remodelling. Lastly, we present an overview of RR animal models and potential future strategies under pre-clinical evaluation.

European Association of Cardiovascular Imaging survey on cardiovascular multimodality imaging in acute myocarditis

AIMS

To assess the current role of cardiac imaging in the diagnosis, management, and follow-up of patients with acute myocarditis (AM) through a European Association of Cardiovascular Imaging survey.

METHODS AND RESULTS

A total of 412 volunteers from 74 countries responded to the survey. Most participants worked in tertiary centres (56%). All participants had access to echocardiography, while 79 and 75% had access to cardiac computed tomography angiography (CCTA) and cardiac magnetic resonance (CMR), respectively. Less than half (47%) had access to myocardial biopsy, and only 5% used this test routinely. CMR was performed within 7 days of presentation in 73% of cases. Non-ischaemic late gadolinium enhancement (LGE, 88%) and high-signal intensity in T2-weighted images (74%) were the most used diagnostic criteria for AM. CCTA was preferred to coronary angiography by 47% of participants to exclude coronary artery disease. Systematic prescription of beta-blockers and angiotensin-converting enzyme inhibitors was reported by 38 and 32% of participants. Around a quarter of participants declared considering LGE burden as a reason to treat. Most participants (90%) reported performing a follow-up echocardiogram, while 63% scheduled a follow-up CMR. The main reason for treatment discontinuation was improvement of left ventricular ejection fraction (89%), followed by LGE regression (60%). In two-thirds of participants, the decision to resume high-intensity sport was influenced by residual LGE.

CONCLUSION

This survey confirms the high utilization of cardiac imaging in AM but reveals major differences in how cardiac imaging is used and how the condition is managed between centres, underlining the need for recommendation statements in this topic.

Atrial and Ventricular Involvement in Acute Myocarditis Patients with Preserved Ejection Fraction: A Single-Center Cardiovascular Magnetic Resonance Study

Cardiac magnetic resonance (CMR) is commonly employed to confirm the diagnosis of acute myocarditis (AM). However, the impact of atrial and ventricular function in AM patients with preserved ejection fraction (EF) deserves further investigation. Therefore, the aim of this study was to explore the incremental diagnostic value of combining atrial and strain functions using CMR in patients with AM and preserved EF. This retrospective study collected CMR scans of 126 consecutive patients with AM (meeting the Lake Louise criteria) and with preserved EF, as well as 52 age- and sex-matched control subjects. Left atrial (LA) and left ventricular (LV) strain functions were assessed using conventional cine-SSFP sequences. In patients with AM and preserved EF, impaired ventricular and atrial strain functions were observed compared to control subjects. These impairments remained significant even in multivariable analysis. The combined model of atrial and ventricular functions proved to be the most effective in distinguishing AM patients with preserved ejection fraction from control subjects, achieving an area under the curve of 0.77 and showing a significant improvement in the likelihood ratio. These findings suggest that a combined analysis of both atrial and ventricular functions may improve the diagnostic accuracy for patients with AM and preserved EF.

Autoimmune Myocarditis, Old Dogs and New Tricks

Autoimmunity significantly contributes to the pathogenesis of myocarditis, underscored by its increased frequency in autoimmune diseases such as systemic lupus erythematosus and polymyositis. Even in cases of myocarditis caused by viral infections, dysregulated immune responses contribute to pathogenesis. However, whether triggered by existing autoimmune conditions or viral infections, the precise antigens and immunologic pathways driving myocarditis remain incompletely understood. The emergence of myocarditis associated with immune checkpoint inhibitor therapy, commonly used for treating cancer, has afforded an opportunity to understand autoimmune mechanisms in myocarditis, with autoreactive T cells specific for cardiac myosin playing a pivotal role. Despite their self-antigen recognition, cardiac myosin-specific T cells can be present in healthy individuals due to bypassing the thymic selection stage. In recent studies, novel modalities in suppressing the activity of pathogenic T cells including cardiac myosin-specific T cells have proven effective in treating autoimmune myocarditis. This review offers an overview of the current understanding of heart antigens, autoantibodies, and immune cells as the autoimmune mechanisms underlying various forms of myocarditis, along with the latest updates on clinical management and prospects for future research.

The Emerging Field of Cardioimmunology: Past, Present and Foreseeable Future

Over the past 30 years, the field of cardioimmunology has moved from being dismissed as a field that was chasing an epiphenomenon of little biological consequence to a scientific discipline that is providing important new insights into the immunologic basis for hypertension, atherosclerosis, myocarditis, pericarditis, autoimmune heart disease, and heart failure. In this article, we will review the conceptual insights and technical breakthroughs that have allowed the field to move forward, as well as the clinical trials in the cardioimmunology space, to provide a historical context for the articles that will appear in the compendium that is focused on the interface between cardioimmunology, myocardial function, and disease.

STING-Targeted PET Imaging for Specific Detection and Therapeutic Monitoring of Myocarditis

Imaging strategies for the specific detection and therapeutic monitoring of myocarditis are still lacking. Stimulator of interferon genes (STING) is a signal transduction molecule involved in an innate immune response. Here, we evaluated the feasibility of the recently developed STING-targeted radiotracer [18F]FBTA for positron emission tomography (PET) imaging to detect myocardial inflammation and monitor treatment in myocarditis mice. [18F]FBTA-PET imaging was performed in myocarditis mice and normal mice to verify the specificity of [18F]FBTA for the diagnosis of myocarditis. We also performed PET imaging in mice with myocarditis treated to verify the ability of [18F]FBTA in therapeutic monitoring. The expression of STING and inflammatory cell types was confirmed by flow cytometry and immunohistochemistry. [18F]FDG-PET imaging of myocarditis was used as a contrast. [18F]FBTA-PET imaging showed that the average radioactive uptake was significantly higher in the hearts of the myocarditis group than in the control group. STING was highly overexpressed in cardiac inflammatory cells, including macrophages, dendritic cells (DCs), and T cells. However, there was no significant difference in cardiac radiotracer uptake of [18F]FDG between the myocarditis group and the control group. Moreover, cardiac uptake of [18F]FBTA was significantly reduced in cyclosporin A-treated myocarditis mice and myocardial STING expression was also significantly reduced after the treatment. Overall, we showed that a STING-targeted PET tracer [18F]FBTA can be used to monitor changes in the inflammatory microenvironment in myocarditis. Besides, [18F]FBTA-PET is also suitable for real-time monitoring of myocarditis treatment, representing a promising diagnostic and therapeutic monitoring approach for myocarditis.

Rationale and design of the French cohort of acute myocarditis diagnosed by cardiac magnetic resonance imaging (MyocarditIRM)

BACKGROUND

Acute myocarditis usually presents as chest pain with rising troponin and normal coronary arteries. Despite frequent favourable evolution at the acute phase, it is associated with heart failure and ventricular rhythm disorders, and is considered the leading cause of sudden cardiac death in young, apparently healthy, adults. There are no specific recommendations for acute myocarditis diagnosis and management, only expert consensus, given the lack of large databases.

AIM

The main objective is to describe the contemporary presentation of acute myocarditis, its management and in-hospital outcomes. Secondary objectives are to investigate survival and event-free survival for up to 10years of follow-up, the determinants of prognosis, the modalities of treatment and follow-up and the gaps between expert consensus and real-life management.

METHODS

MyocarditIRM is a prospective multicentre cohort that enrolled 803 consecutive patients with acute myocarditis in 49 participating centres in France between 01 May 2016 and 28 February 2019. The diagnosis of acute myocarditis was acknowledged by cardiac magnetic resonance, using the Lake Louise Criteria. Exclusion criteria were age<18years, lack of health coverage, contraindication to cardiac magnetic resonance and refusal to participate. Detailed information was collected prospectively, starting at admission. Cardiac magnetic resonance imaging (diagnosis and follow-up) is analysed centrally by the certified core laboratory IHU ICAN. Ten years of follow-up for each patient is ensured by linking with the French National Health Database, and includes information on death, hospital admissions, major clinical events and drug consumption.

CONCLUSION

This prospective cohort with long-term follow-up represents the largest database on acute myocarditis worldwide, and will improve knowledge about its presentation, management and outcomes.

Acute myocarditis: an overview of pathogenesis, diagnosis and management

Acute myocarditis encompasses a diverse presentation of inflammatory cardiomyopathies with infectious and non-infectious triggers. The clinical presentation is heterogeneous, from subtle symptoms like mild chest pain to life-threatening fulminant heart failure requiring urgent advanced hemodynamic support. This review provides a comprehensive overview of the current state of knowledge regarding the pathogenesis, diagnostic approach, management strategies, and directions for future research in acute myocarditis. The pathogenesis of myocarditis involves interplay between the inciting factors and the subsequent host immune response. Infectious causes, especially cardiotropic viruses, are the most frequently identified precipitants. However, autoimmune processes independent of microbial triggers, as well as toxic myocardial injury from drugs, chemicals or metabolic derangements also contribute to the development of myocarditis through diverse mechanisms. Furthermore, medications like immune checkpoint inhibitor therapies are increasingly recognized as causes of myocarditis. Elucidating the nuances of viral, autoimmune, hypersensitivity, and toxic subtypes of myocarditis is key to guiding appropriate therapy. The heterogeneous clinical presentation coupled with non-specific symptoms creates diagnostic challenges. A multifaceted approach is required, incorporating clinical evaluation, electrocardiography, biomarkers, imaging studies, and endomyocardial biopsy. Cardiovascular magnetic resonance imaging has become pivotal for non-invasive assessment of myocardial inflammation and fibrosis. However, biopsy remains the gold standard for histological classification and definitively establishing the underlying etiology. Management relies on supportive care, while disease-specific therapies are limited. Although some patients recover well with conservative measures, severe or fulminant myocarditis necessitates aggressive interventions such as mechanical circulatory support devices and transplantation. While immunosuppression is beneficial in certain histological subtypes, clear evidence supporting antiviral or immunomodulatory therapies for the majority of acute viral myocarditis cases remains insufficient. Substantial knowledge gaps persist regarding validated diagnostic biomarkers, optimal imaging surveillance strategies, evidence-based medical therapies, and risk stratification schema. A deeper understanding of the immunopathological mechanisms, rigorous clinical trials of targeted therapies, and longitudinal outcome studies are imperative to advance management and improve the prognosis across the myocarditis spectrum.

Acute lymphocytic myocarditis characterized by cardiogenic shock and conduction system abnormalities in patients with Hashimoto's thyroiditis: a case report and review of literature

Background

Acute myocarditis (AM) is an inflammatory heart disease that may occur as a consequence of autoimmune disorders. Although the correlation between myocarditis and hyperthyroidism has been reported in the literature, the association with hypothyroidism is less frequent.

Case summary

We describe a characteristic case of lymphocytic acute myocarditis deteriorated into cardiogenic shock due to Hashimoto's thyroiditis treated with vasopressor and inotropic drugs in combination with corticosteroid. On admission, electrocardiography revealed a sinus tachycardia with 1st degree atrioventricular (AV) block, right bundle branch block (RBBB), and left anterior fascicular block. Laboratory tests demonstrated a severe hypothyroidism and high-titre serum of antibodies against thyroglobulin. She presented a favourable clinical course, restoring haemodynamic stability. A resolution of hypothyroidism and a progressive reduction of the value of antibodies against thyroglobulin occurred. On Day 35, the patient was discharged showing on electrocardiogram the occurrence of left posterior fascicular block, disappearance of 1st degree AV block and partial improvement of RBBB along with the normalization of the left ventricular contractility abnormalities on echocardiography.

Discussion

Autoimmune features, mostly Hashimoto's thyroiditis, are associated in lymphocytic acute myocarditis to a worse prognosis and an increased risk of recurrence. More studies are needed to elucidate the underlying mechanism.

Prevalence of Pathogenic Variants in Cardiomyopathy-Associated Genes in Acute Myocarditis: A Systematic Review and Meta-Analysis

BACKGROUND

Acute myocarditis is an inflammatory condition that may precede the development of dilated or arrhythmogenic cardiomyopathy.

OBJECTIVES

The aim of this study was to investigate the reported prevalence of pathogenic or likely pathogenic (P/LP) variants in cardiomyopathy-associated genes in patients with acute myocarditis.

METHODS

For this systematic review and meta-analysis, the PubMed and Embase databases were searched on March 4, 2023. Observational studies evaluating the prevalence of P/LP variants in cardiomyopathy-associated genes in patients with acute myocarditis were included. Studies were stratified into adult and pediatric age groups and for the following scenarios: 1) complicated myocarditis (ie, presenting with acute heart failure, reduced left ventricular ejection fraction, or life-threatening ventricular arrhythmias); and 2) uncomplicated myocarditis. The study was registered with the International Prospective Register of Systematic Reviews (CRD42023408668) and followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

Of 732 studies identified, 8 met the inclusion criteria, providing data for 586 patients with acute myocarditis. A total of 89 P/LP variants in cardiomyopathy-associated genes were reported in 85 patients. For uncomplicated myocarditis, the pooled prevalence was 4.2% (95% CI: 1.8%-7.4%; I2 = 1.4%), whereas for complicated myocarditis, the pooled prevalence was 21.9% (95% CI: 14.3%-30.5%; I2 = 38.8%) and 44.5% (95% CI: 22.7%-67.4%; I2 = 52.8%) in adults and children, respectively. P/LP variants in desmosomal genes were predominant in uncomplicated myocarditis (64%), whereas sarcomeric gene variants were more prevalent in complicated myocarditis (58% in adults and 71% in children).

CONCLUSIONS

Genetic variants are present in a large proportion of patients with acute myocarditis. The prevalence of genetic variants and the genes involved vary according to age and clinical presentation.

Innate and adaptive immunity in acute myocarditis

Acute myocarditis is an acute inflammatory cardiomyopathy associated with cardiac damage triggered by a virus or a pathological immune activation. It may present with a wide range of clinical presentations, ranging from mild symptoms to severe forms like fulminant myocarditis, characterized by hemodynamic compromise and cardiogenic shock. The immune system plays a central role in the pathogenesis of myocarditis. In fact, while its function is primarily protective, aberrant responses can be detrimental. In this context, both innate and adaptive immunity play pivotal roles; notably, the innate system offers a non-specific and immediate defense, while the adaptive provides specialized protection with immunological memory. However, dysregulation in these systems can misidentify cardiac tissue, triggering autoimmune reactions and possibly leading to significant cardiac tissue damage. This review highlights the importance of innate and adaptive immune responses in the progression and treatment of acute myocarditis.

Interleukin-1 Inhibition for the Prevention and Treatment of Heart Failure

ABSTRACT

Heart failure (HF) is a complex syndrome that remains a leading cause of morbidity and mortality worldwide. Abundant evidence suggests inflammation plays a key role in the development and perpetuation of HF, but there are currently no anti-inflammatory treatments approved for use in HF. Interleukin-1, the prototypical proinflammatory cytokine, has been implicated in adverse cardiac remodeling and left ventricular dysfunction. Multiple early phase clinical trials using interleukin-1 blockade in patients at risk for or diagnosed with HF have suggested favorable safety and efficacy in reducing inflammatory biomarkers, as well as positive signals in surrogate and clinical end points. Additional large scale clinical trials are urgently needed to confirm the safety and efficacy of this therapeutic approach specifically in HF. In this narrative review, we discuss current evidence regarding interleukin-1 blockade in the prevention and treatment of HF.

COVID-19 Vaccination-Related Myocarditis: What We Learned From Our Experience and What We Need to Do in The Future

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 has led to a global health crisis with substantial mortality and morbidity. To combat the COVID-19 pandemic, various vaccines have been developed, but unexpected serious adverse events including vaccine-induced thrombotic thrombocytopenia, carditis, and thromboembolic events have been reported and became a huddle for COVID-19 vaccination. Vaccine-related myocarditis (VRM) is a rare but significant adverse event associated primarily with mRNA vaccines. This review explores the incidence, risk factors, clinical presentation, pathogenesis, management strategies, and outcomes associated with VRM. The incidence of VRM is notably higher in male adolescents and young adults, especially after the second dose of mRNA vaccines. The pathogenesis appears to involve an immune-mediated process, but the precise mechanism remains mostly unknown so far. Most studies have suggested that VRM is mild and self-limiting, and responds well to conventional treatment. However, a recent nationwide study in Korea warns that severe cases, including fulminant myocarditis or death, are not uncommon in patients with COVID-19 VRM. The long-term cardiovascular consequences of VRM have not been well understood and warrant further investigation. This review also briefly addresses the critical balance between the substantial benefits of COVID-19 vaccination and the rare risks of VRM in the coming endemic era. It emphasizes the need for continued surveillance, research to understand the underlying mechanisms, and strategies to mitigate risk. Filling these knowledge gaps would be vital to refining vaccination recommendations and improving patient care in the evolving COVID-19 pandemic landscape.

Incidence and Predictors for Recurrence of Ventricular Arrhythmia Presenting During Acute Myocarditis: A Multicenter Study

BACKGROUND

Management of acute myocarditis (AM) patients experiencing ventricular arrhythmia (VA) during acute illness is controversial, especially regarding early implantable cardioverter-defibrillator (ICD) implantation.

OBJECTIVES

The purpose of this study was to evaluate the prevalence of and find predictors for long-term sustained VA recurrence and overall mortality among AM patients with VA.

METHODS

This was a multicenter retrospective analysis of AM patients (verified by cardiac magnetic resonance imaging or myocardial biopsy) with documented VA during the acute illness ("initial VA"). Patients with history of myocardial infarction, heart failure, or VA were excluded. The study endpoint was a composite of sustained VA and overall mortality during follow-up.

RESULTS

The study included 69 AM patients with initial VA: sustained monomorphic ventricular tachycardia (MMVT) (n = 25), sustained polymorphic ventricular tachycardia (VT)/ventricular fibrillation (n = 13), and nonsustained VT (n = 31). Age was 44 ± 13 years, and 23 of 69 (33.3%) were women. During median follow-up of 5.5 years, 27 of 69 (39%) patients reached the composite endpoint including sustained VA (n = 24) and death (n = 11). Initial MMVT, predischarge left ventricular dysfunction (left ventricular ejection fraction <50%), and anteroseptal delayed enhancement on cardiac magnetic resonance imaging were significantly associated with the composite endpoint. On multivariable analysis, initial MMVT (HR: 5.17; 95% CI: 1.81-14.6; P = 0.001) and predischarge LV dysfunction (HR: 4.57; 95% CI: 1.83-11.5; P = 0.005) were independently associated with the composite endpoint. Using these 2 predictors, we could delineate subgroups with low (∼4%), medium (∼42%), and high (∼82%) 10-year incidence of composite endpoint.

CONCLUSIONS

AM patients presenting with VA have high incidence of sustained VA recurrence and mortality posthospitalization. Initial MMVT and predischarge LV dysfunction are independently associated with VA recurrence and mortality. Implantable cardioverter-defibrillator implantation may be considered in such high-risk patients.

Rate of cardiovascular events up to 8 years after uncomplicated myocarditis: a nationwide cohort study

AIMS

While prognosis of acute myocarditis with uncomplicated presentation is perceived as benign, data on long-term outcomes are scarce. We evaluated rates of myocarditis-associated cardiovascular events after a first-time hospitalization with uncomplicated acute myocarditis in patients without known heart disease.

METHODS AND RESULTS

In this retrospective nationwide population-based cohort study from 2013 to 2020, hospitalized patients with uncomplicated acute myocarditis but without known heart disease were 1:1 propensity score-matched with surgical controls hospitalized for laparoscopic appendectomy. As assessed in time-to-event analyses, the primary outcome was a composite of rehospitalization for myocarditis, pericardial disease, heart failure and its complications, arrhythmias, implantation of cardiac devices, and heart transplant. After matching, we identified 1439 patients with uncomplicated acute myocarditis (median age of 35 years, 74.0% male) and 1439 surgical controls (median age of 36 years, 74.4% male). Over a median follow-up of 39 months, compared with surgical controls, the hazard ratio for the primary composite outcome was 42.3 [95% confidence interval (CI) 17.4-102.8], corresponding to an incidence rate of 43.7 vs. 0.9 per 1000 patient-years (py) and an incidence rate difference of 42.7 (95% CI 36.7-48.8) per 1000 py.

CONCLUSION

Patients hospitalized with uncomplicated acute myocarditis and no known prior heart disease were associated with substantial risk for cardiovascular events over a follow-up of up to 8 years. This calls for a more efficient therapeutic management of this population of patients.

The Role of the Immune System in Pathobiology and Therapy of Myocarditis: A Review

The role of the immune system in myocarditis onset and progression involves a range of complex cellular and molecular pathways. Both innate and adaptive immunity contribute to myocarditis pathogenesis, regardless of its infectious or non-infectious nature and across different histological and clinical subtypes. The heterogeneity of myocarditis etiologies and molecular effectors is one of the determinants of its clinical variability, manifesting as a spectrum of disease phenotype and progression. This spectrum ranges from a fulminant presentation with spontaneous recovery to a slowly progressing, refractory heart failure with ventricular dysfunction, to arrhythmic storm and sudden cardiac death. In this review, we first examine the updated definition and classification of myocarditis at clinical, biomolecular and histopathological levels. We then discuss recent insights on the role of specific immune cell populations in myocarditis pathogenesis, with particular emphasis on established or potential therapeutic applications. Besides the well-known immunosuppressive agents, whose efficacy has been already demonstrated in human clinical trials, we discuss the immunomodulatory effects of other drugs commonly used in clinical practice for myocarditis management. The immunological complexity of myocarditis, while presenting a challenge to simplistic understanding, also represents an opportunity for the development of different therapeutic approaches with promising results.

Diagnosis and Management of Cardiac Sarcoidosis: A Scientific Statement From the American Heart Association

Cardiac sarcoidosis is an infiltrative cardiomyopathy that results from granulomatous inflammation of the myocardium and may present with high-grade conduction disease, ventricular arrhythmias, and right or left ventricular dysfunction. Over the past several decades, the prevalence of cardiac sarcoidosis has increased. Definitive histological confirmation is often not possible, so clinicians frequently face uncertainty about the accuracy of diagnosis. Hence, the likelihood of cardiac sarcoidosis should be thought of as a continuum (definite, highly probable, probable, possible, low probability, unlikely) rather than in a binary fashion. Treatment should be initiated in individuals with clinical manifestations and active inflammation in a tiered approach, with corticosteroids as first-line treatment. The lack of randomized clinical trials in cardiac sarcoidosis has led to treatment decisions based on cohort studies and consensus opinions, with substantial variation observed across centers. This scientific statement is intended to guide clinical practice and to facilitate management conformity by providing a framework for the diagnosis and management of cardiac sarcoidosis.

Case Report: Three cases of clinically suspected viral myocarditis with recovery of left ventricular dysfunction

Viral myocarditis is an important cause of non-ischemic cardiomyopathy. Multiple clinical manifestations have been reported, including acute heart failure, cardiogenic shock, and ventricular arrhythmias. We present three patients with clinically suspected viral myocarditis causing acute heart failure. Serum coxsackievirus B antibodies were positive in all three patients. Each case resulted in significant clinical improvement with hemodynamic support and acute recovery of left ventricular ejection fraction. Despite an initial critical presentation concerning for cardiogenic shock, we highlight three cases of clinically suspected coxsackie myocarditis with an excellent short-term prognosis.

Long COVID in Children, Adults, and Vulnerable Populations: A Comprehensive Overview for an Integrated Approach

Long COVID affects both children and adults, including subjects who experienced severe, mild, or even asymptomatic SARS-CoV-2 infection. We have provided a comprehensive overview of the incidence, clinical characteristics, risk factors, and outcomes of persistent COVID-19 symptoms in both children and adults, encompassing vulnerable populations, such as pregnant women and oncological patients. Our objective is to emphasize the critical significance of adopting an integrated approach for the early detection and appropriate management of long COVID. The incidence and severity of long COVID symptoms can have a significant impact on the quality of life of patients and the course of disease in the case of pre-existing pathologies. Particularly, in fragile and vulnerable patients, the presence of PASC is related to significantly worse survival, independent from pre-existing vulnerabilities and treatment. It is important try to achieve an early recognition and management. Various mechanisms are implicated, resulting in a wide range of clinical presentations. Understanding the specific mechanisms and risk factors involved in long COVID is crucial for tailoring effective interventions and support strategies. Management approaches involve comprehensive biopsychosocial assessments and treatment of symptoms and comorbidities, such as autonomic dysfunction, as well as multidisciplinary rehabilitation. The overall course of long COVID is one of gradual improvement, with recovery observed in the majority, though not all, of patients. As the research on long-COVID continues to evolve, ongoing studies are likely to shed more light on the intricate relationship between chronic diseases, such as oncological status, cardiovascular diseases, psychiatric disorders, and the persistent effects of SARS-CoV-2 infection. This information could guide healthcare providers, researchers, and policymakers in developing targeted interventions.

Changes in the epidemiology and clinical characteristics of viral gastroenteritis among hospitalized children in the Mainland of China: a retrospective study from 2016 to 2020

BACKGROUND

Acute gastroenteritis (AGE) causes significant morbidity in children worldwide; however, the disease burden of children hospitalized with viral gastroenteritis in China has been rarely described. Through this study, we analyzed the data of hospitalized children with viral gastroenteritis to explore the changes in the epidemiology and clinical characteristics of viral gastroenteritis in the mainland of China.

METHODS

Data were extracted from Futang Children's Medical Development Research Center (FRCPD), between 2016 and 2020, across 27 hospitals in 7 regions. The demographics, geographic distribution, pathogenic examination results, complications, hospital admission date, length of hospital stays, hospitalization charges and outcomes were collected and analyzed.

RESULTS

Viral etiological agents included rotavirus (RV), adenovirus (ADV), norovirus (NV) and coxsackievirus (CV) that were detected in 25,274 (89.6%), 1,047 (3.7%), 441 (1.5%) and 83 (0.3%) cases. There was a higher prevalence of RV and NV infection among children younger than 3 years of age. RV and NV had the highest detection rates in winter, while ADV in summer. Children with viral gastroenteritis were often accompanied by other diseases, such as myocardial diseases (10.98-31.04%), upper respiratory tract diseases (1.20-20.15%), and seizures (2.41-14.51%). Among those cases, the co-infection rate with other pathogens was 6.28%, with Mycoplasma pneumoniae (M. pneumoniae), Epstein-Barr virus (EBV), and influenza virus (FLU) being the most common pathogens. The median length of stay was 5 days, and the median cost of hospitalization corresponded to587 US dollars.

CONCLUSIONS

This finding suggests that viral gastroenteritis, especially those caused by RV, is a prevalent illness among younger children. Co-infections and the presence of other diseases are common. The seasonality and regional variation of viral etiological agents highlight the need for targeted prevention and control measures. Although viral gastroenteritis rarely leads to death, it also results in a significant economic burden on healthcare systems.

Cardiovascular magnetic resonance in the identification of extra-cardiac causes of myocarditis: a case series

Background

Myocarditis is challenging to diagnose due to its varied presentations. Endomyocardial biopsy is the gold standard for diagnosis, but its invasive nature has led to alternative non-invasive modalities, notably cardiovascular magnetic resonance (CMR). Identifying the precise aetiology of myocarditis is crucial for effective treatment, yet extra-cardiac causes are often overlooked. In this paper, we spotlight the underexplored role of CMR in diagnosing extra-cardiac aetiologies, utilizing three insightful cases for illustration.

Case summary

The first case is a 31-year-old patient with myocarditis secondary to a pyogenic liver abscess, identified through CMR, who improved after abscess drainage. The second case involves a 54-year-old patient with myocarditis attributed to adult T-cell leukaemia-lymphoma, with the loco-regional thickening process identified thanks to CMR. This patient had an unfavourable disease progression due to the underlying malignancy. The third case concerns a 23-year-old patient suffering from myocarditis associated with pneumonia, again illustrated effectively through CMR imaging, who recovered after antibiotic treatment.

Discussion

These cases underline the overlooked potential of CMR in diagnosing extra-cardiac aetiologies of myocarditis, even though such causes are rare. Despite current guidelines recognizing the importance of identifying the aetiology of myocarditis, they do not explicitly address the role of CMR in diagnosing extra-cardiac aetiologies. This article, therefore, proposes that future guidelines could emphasize the utility of CMR in exploring these causes, potentially leading to more accurate diagnoses and improved patient outcomes. It also advocates for a comprehensive, multidisciplinary approach to myocarditis diagnosis, encouraging vigilance for potential loco-regional causes, and calls for further research in this area.

Sacubitril/Valsartan inhibits M1 type macrophages polarization in acute myocarditis by targeting C-type natriuretic peptide

Studies have shown that Sacubitril/valsartan (Sac/Val) can reduce myocardial inflammation in myocarditis mice, in addition to its the recommended treatment of heart failure. However, the underlying mechanisms of Sac/Val in myocarditis remain unclear. C-type natriuretic peptide (CNP), one of the targeting natriuretic peptides of Sac/Val, was recently reported to exert cardio-protective and anti-inflammatory effects in cardiovascular systems. Here, we focused on circulating levels of CNP in patients with acute myocarditis (AMC) and whether Sac/Val modulates inflammation by targeting CNP in experimental autoimmune myocarditis (EAM) mice as well as LPS-induced RAW 264.7 cells and bone marrow derived macrophages (BMDMs) models. Circulating CNP levels were higher in AMC patients compared to healthy controls, and these levels positively correlated with the elevated inflammatory cytokines IL-6 and monocyte count. In EAM mice, Sac/Val alleviated myocardial inflammation while augmenting circulating CNP levels rather than BNP and ANP, accompanied by reduction in intracardial M1 macrophage infiltration and expression of inflammatory cytokines IL-1β, TNF-α, and IL-6. Furthermore, Sac/Val inhibited CNP degradation and directly blunted M1 macrophage polarization in LPS-induced RAW 264.7 cells and BMDMs. Mechanistically, the effects might be mediated by the NPR-C/cAMP/JNK/c-Jun signaling pathway apart from NPR-B/cGMP/NF-κB pathway. In conclusion, Sac/Val exerts a protective effect in myocarditis by increasing CNP concentration and inhibiting M1 macrophages polarization.

Chinese Society of Cardiology guidelines on the diagnosis and treatment of adult fulminant myocarditis

Fulminant myocarditis is an acute diffuse inflammatory disease of myocardium. It is characterized by acute onset, rapid progress and high risk of death. Its pathogenesis involves excessive immune activation of the innate immune system and formation of inflammatory storm. According to China's practical experience, the adoption of the "life support-based comprehensive treatment regimen" (with mechanical circulation support and immunomodulation therapy as the core) can significantly improve the survival rate and long-term prognosis. Special emphasis is placed on very early identification,very early diagnosis,very early prediction and very early treatment.

Case report: acute myocarditis in two patients with coronary artery disease presenting with chest pain-thinking outside the box

Background

In a subset of patients, acute myocarditis (AM) may mimic acute myocardial infarction, with a similar clinical presentation characterized by chest pain, electrocardiogram (ECG) changes consistent with acute coronary syndromes (ACS), and serum markers increment.

Case summary

We present two cases of infarct-like myocarditis in patients with known coronary artery disease (CAD), in which the discrepancy between transthoracic echocardiogram findings, ECG, and angiography prompted us to look beyond the simplest diagnosis. In these cases, making a prompt and correct diagnosis is pivotal to address adequate therapy and establish a correct prognosis.

Discussion

The right diagnosis can avoid unnecessary coronary revascularizations and subsequent antiplatelet therapy that may be associated with an increased haemorrhagic risk. Moreover, it allows setting up guideline-directed therapy for myocarditis, proper follow-up, as well as recommending abstention from physical activity.

Current Treatment and Immunomodulation Strategies in Acute Myocarditis

ABSTRACT

Myocarditis is an inflammatory disease of the myocardium characterized by a great heterogeneity of presentation and evolution. Treatment of myocarditis is often supportive, and the evidence for immunosuppression is scarce and debated. Conventional treatment is based on clinical presentation, ranging from conservative to advanced mechanical assist devices. In this setting, immunosuppression and immunomodulation therapies are mostly reserved for patients presenting with major clinical syndromes. In this review, we will summarize the current evidence and strategies for conventional and immunosuppressive treatments for patients presenting with acute myocarditis.

Long-term efficacy and safety of tailored immunosuppressive therapy in immune-mediated biopsy-proven myocarditis: A propensity-weighted study

AIMS

Standardized immunosuppressive therapy (IS) had been previously investigated in biopsy-proven (BP) lymphocytic myocarditis with heart failure (HF). This study evaluated efficacy and safety of tailored IS in BP immune-mediated myocarditis, irrespective of histology and clinical presentation.

METHODS AND RESULTS

Consecutive BP myocarditis patients treated with long-term tailored IS on top of optimal medical therapy (OMT), were compared with OMT non-IS controls using propensity-score weighting. The primary outcome was a composite of death or heart transplant, the secondary outcome was a composite of biventricular function, New York Heart Association (NYHA) class variation, and relapse. IS was managed by a multidisciplinary Cardioimmunology Team, involved a safety checklist and active patients' education. Ninety-one IS patients were compared with 267 non-IS patients. IS patients more frequently had systemic immune-mediated diseases (35% vs. 9.7%), lower baseline echocardiographic left ventricular ejection fraction (35% vs. 43%), lower right ventricular fractional area change (34% vs. 41%) and higher frequency of active lymphocytic, eosinophilic and giant cell myocarditis (71% vs. 58%, 12% vs. 1.1%, and 6.6% vs. 1.5%, respectively). At 5-year follow up, no difference was observed in the primary outcome (survival rate 93% in IS vs. 87% in non-IS), but IS patients had a higher relapse rate. Thus, IS patients, with a lower biventricular function and a higher risk profile at baseline, presented similar biventricular function and NYHA class to non-IS patients at follow-up. Minor adverse drug reactions occurred in 13% of patients, all resolved with therapy switch.

CONCLUSIONS

Prolonged tailored IS is effective and safe in BP immune-mediated myocarditis irrespective of histology and clinical presentation.

Eosinophilic myocarditis: systematic review

OBJECTIVE

In clinical practice, patients with eosinophilic myocarditis (EM) may forgo the gold standard diagnostic procedure, endomyocardial biopsy (EMB), although it is highly recommended in guidelines. This systematic review aims to summarise current approaches in diagnosing and treating EM with a particular emphasis on the utilisation and value of alternative diagnostic methods.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, we searched MEDLINE and EMBASE for all peer-reviewed articles using the keywords "eosinophilic myocarditis" from their inception to 10 September 2022.

RESULTS

We included 239 articles, including 8 observational studies and 274 cases, in this review. The median patient age was 45 years. Initial presentations were non-specific, including dyspnoea (50.0%) and chest pain (39.4%). The aetiologies of EM were variable with the most common being idiopathic (28.8%) and eosinophilic granulomatosis polyangiitis (19.3%); others included drug-induced (13.1%) and hypereosinophilic syndrome (12.8%). 82.4% received an EM diagnosis by EMB while 17.6% were diagnosed based on clinical reasoning and cardiac MRI (CMR). CMR-diagnosed patients exhibited a better risk profile at diagnosis, particularly higher left ventricular ejection fraction and less need for inotropic or mechanical circulatory supports. Glucocorticoids were the primary treatment with variability in dosages and regimens.

CONCLUSION

EMB is the mainstay for diagnostic testing for EM. CMR is potentially helpful for screening in appropriate clinical scenarios. Regarding treatment, there is no consensus regarding the optimal dosage of corticosteroids. Large clinical trials are warranted to further explore the utility of CMR in the diagnosis of EM and steroid regimen in treating EM.

Multisystemic Inflammation Influences Prognosis in Fulminant Lymphocytic Myocarditis

BACKGROUND

Multisystem inflammatory syndrome (MIS) is a hyperinflammatory shock associated with cardiac dysfunction and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, there are no reports on using MIS criteria, such as multisystemic inflammation (MSI) in fulminant myocarditis, without SARS-CoV-2 infection. This study investigated the differences in clinical characteristics and course between patients with fulminant lymphocytic myocarditis (FLM) plus MSI and those without MSI.

METHODS AND RESULTS

This multicenter retrospective cohort study included 273 patients with FLM registered in the JROAD-DPC database between April 2014 and March 2017. We evaluated the presence of MSI using criteria modified from previously reported MIS criteria and compared the characteristics and risk of mortality or heart transplantation between FLM patients with MSI and without MSI. Of the 273 patients with FLM, 107 (39%) were diagnosed with MSI. The MSI group was younger (44 vs. 57 years; P<0.0001) and had more females (50% vs. 36%; P=0.0236), a higher incidence of pericardial effusion (58% vs. 40%; P=0.0073), and a lower 90-day mortality rate (19% vs. 33%; P=0.0185) than the non-MSI group. The risk of mortality at 90 days was lower in FLM patients aged <50 years with MSI aged <50 years than in those without MSI (P=0.0463).

CONCLUSIONS

These results suggest that MSI may influence the prognosis of FLM, especially in patients aged <50 years.

The Epidemiology of COVID-19 Vaccine-Induced Myocarditis

Background

In December 2019, the emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) led to the COVID-19 pandemic, with millions of deaths worldwide. Vaccine breakthroughs in late 2020 resulted in the authorization of COVID-19 vaccines. While these vaccines have demonstrated efficacy, evidence from vaccine safety monitoring systems around the globe supported a causal association between COVID-19 vaccines, in particular those using mRNA technology, i.e., Moderna's mRNA-1273 and Pfizer-BioNTech's BNT162b2, and myocarditis.

Objective

This paper aims to investigate the epidemiology of mRNA COVID-19 vaccine-induced myocarditis, including age, ethnicity, and gender associations with these vaccines. It also discusses the immunopathophysiological mechanisms of mRNA COVID-19 vaccine-associated myocarditis and outlines principles of diagnosis, clinical presentation, and management.

Methods

A literature review was conducted using PubMed, Embase, and Queen Mary University of London Library Services databases. Search terms included "myocarditis," "coronavirus disease 2019," "SARS-CoV-2," "mRNA Covid-19 vaccines," "Covid vaccine-associated myocarditis," "epidemiology," "potential mechanisms," "myocarditis diagnosis," and "myocarditis management."

Results

While the definite mechanism of mRNA COVID-19 vaccine-associated myocarditis remains ambiguous, potential mechanisms include molecular mimicry of spike proteins and activation of the adaptive immune response with dysregulated cytokine expression. Male predominance in COVID-19 vaccine-induced myocarditis may be attributed to sex hormones, variations in inflammatory reactions, coagulation states based on gender, and female-specific protective factors. Moreover, an analysis of diagnostic and management strategies reveals a lack of consensus on acute patient presentation management.

Conclusion

In contrast to viral infections that stand as the predominant etiological factor for myocarditis with more severe consequences, the mRNA COVID-19 vaccination elicits a mild and self-limiting manifestation of the condition. There is currently insufficient evidence to confirm the definite underlying mechanism of COVID-19 vaccine-associated myocarditis. Further research is needed to develop preventive and therapeutic solutions in this context.

Clinical Application of Extracorporeal Membrane Oxygenation in the Treatment of Fulminant Myocarditis

Fulminant myocarditis (FM) is a rare but serious clinical syndrome which can be characterized by the rapid deterioration of cardiac function, with cardiogenic shock (CS) and arrhythmic electrical storms being common presentations, often requiring adjunctive support with mechanical circulatory devices. With the development of mechanical circulatory support (MCS) devices, there are now more and more studies investigating the application of MCS in FM patients, and the use of extracorporeal membrane oxygenation (ECMO) to treat FM has shown good survival rates. This review elucidates the treatment of FM, and the application and clinical outcomes associated with ECMO intervention.

Case report: acute myocarditis complicated with persistent complete heart block: a clinical dilemma when myocardial inflammation remains

Background

Atrioventricular conduction abnormalities due to acute myocarditis are typically transient and do not require ventricular pacing beyond the acute phase of myocardial inflammation. Notwithstanding, selective injury and necrosis of the heart's conduction system may lead to persistent complete heart block (CHB) requiring device implantation.

Case summary

We report the case of a 23-year-old man with acute lymphocytic myocarditis complicated by cardiogenic shock, cardiac arrest due to ventricular fibrillation, and persistent CHB. Endomyocardial biopsy (EMB) showed signs of subacute myocarditis, with no evidence of granulomas or giant cells, nor criteria for eosinophilic myocarditis. Aetiological work-up found serological evidence of previous Epstein-Barr virus (EBV) infection; Borrelia burgdorferi serology for Lyme disease was negative. The real time-polymerase chain reaction (RT-PCR) of the EMB was positive for the presence of EBV DNA, but in situ hybridization for viral ribosomal RNA (rRNA) was negative. The patient progressed favourably, and left ventricle ejection fraction recovered 2 weeks after initial presentation. However, CHB persisted for more than 3 weeks, and the patient underwent definitive pacemaker implantation with left bundle branch pacing.

Discussion

Persistent CHB after acute myocarditis is generally considered unlikely, but in rare circumstances the damage portended by inflammation may be irreversible. Besides the play of chance, possible mechanisms behind the apparent predilection for the conduction system of the myocardium warrant further research.