Efficacy and safety of mycophenolate mofetil in patients with virus-negative lymphocytic myocarditis: A prospective cohort study

Successful treatment of fulminant and recurrent lymphocytic myocarditis with calcineurin inhibitors

Lymphocytic myocarditis (LM) is primarily triggered by various factors including viral infections and subsequent immune responses. While rare, some patients with LM experience recurrence with a life-threatening fulminant form. Although combining steroids and immunosuppressants, such as azathioprine and mycophenolate mofetil, has demonstrated favourable outcomes in patients with LM, their efficacy is limited to the chronic phase. Indeed, various immunosuppressants have been used for LM with fulminant manifestation; however, their evidence remains lacking. In our case series, two patients with LM experienced fulminant relapses during steroid tapering, and another presented persistent cardiac enzymes elevation despite steroid therapies. Consequently, we initiated calcineurin inhibitors alongside steroids, resulting in well-controlled clinical courses without further recurrence of LM and significant adverse effects. Our cases suggest calcineurin inhibitors as therapeutic options for managing steroid-resistant LM with fulminant relapse.

Therapeutic strategies for primary heart involvement in systemic sclerosis

Primary heart involvement (pHI) is frequent in systemic sclerosis (SSc), even though often underdiagnosed. SSc-pHI has been recently defined as cardiac abnormalities that are predominantly attributable to SSc rather than other causes and/or complications. SSc-pHI represents a major determinant of mortality in SSc, accounting alone for about 12% of disease-related deaths; its early recognition and promptly therapeutic interventions are therefore crucial. Both perfusion defects and myocardial inflammation contribute to the occurrence of myocardial fibrosis that precipitates myocardial remodeling, potentially leading to heart failure and arrhythmic complications. To date, clear evidence and guidelines for effectively managing SSc pHI are not established yet, resulting in a lack of a defined therapeutic algorithm. In this review we summarize the most recent scientific literature on the prevailing therapeutic strategies and interventions to manage SSc-pHI, with particular focus on therapeutic strategies to counteract the 3 major pathogenic events of the disease, i.e. microvascular damage, myocardial inflammation and myocardial fibrosis.

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.

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.

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.

Diagnosis and management of primary heart involvement in systemic sclerosis

PURPOSE OF REVIEW

In systemic sclerosis (SSc) primary heart involvement (pHI) is frequent, even though often unrecognized due to its occult nature and to the lack of a specific diagnostic algorithm. The purpose of this review is to report the state of the art of the evidence in the current literature, as well as the overall diagnostic modalities and therapeutic strategies for primary heart involvement in SSc.

RECENT FINDINGS

SSc-pHI is defined by the presence of cardiac abnormalities that are predominantly attributable to SSc rather than other causes and/or complications; it may be sub-clinical and must be confirmed through diagnostic investigations. Novel electrocardiographic analysis and cardiac magnetic resonance (CMR) with mapping techniques have been recently proposed, showing a great utility in the early identification of SSc-pHI and in the noninvasive characterization of myocardial tissue. Immunosuppressive therapy emerged as fundamental to curb myocardial inflammation, and recent preclinical and clinical data support the role of antifibrotic drugs to treat SSc-pHI.

SUMMARY

our review will help clinicians to properly integrate the available diagnostic modalities for the assessment of SSc-pHI. The ultimate goal is to propose a feasible diagnostic algorithm for the early identification of patients with SSc-pHI, and a schematic therapeutic approach to manage SSc-pHI.

Fulminant Myocarditis: When One Size Does Not Fit All - A Critical Review of the Literature

Fulminant myocarditis, rather than being a distinct form of myocarditis, is instead a peculiar clinical presentation of the disease. The definition of fulminant myocarditis has varied greatly in the last 20 years, leading to conflicting reports on prognosis and treatment strategies, mainly because of varied inclusion criteria in different studies. The main conclusion of this review is that fulminant myocarditis may be due to different histotypes and aetiologies that can be diagnosed only by endomyocardial biopsy and managed by aetiology-directed treatment. This life-threatening presentation requires rapid, targeted management both in the short term (mechanical circulatory support, inotropic and antiarrhythmic treatment and endomyocardial biopsy) and in the long term (including prolonged follow-up). Fulminant presentation has also recently been identified as a risk factor for worsened prognosis, even long after the resolution of the acute phase of myocarditis.

Immunosuppressive Therapy of Biopsy-Proven, Virus-Negative, Autoimmune/Immune-Mediated Myocarditis-Focus on Azathioprine: A Review of Existing Evidence and Future Perspectives

The use of immunosuppressive therapy (IT) in biopsy-proven, autoimmune/immune-mediated (AI), virus-negative myocarditis has become the standard of care. In particular, according to recent guidelines, azathioprine (AZA), in association with steroids, is a cornerstone of first-line therapy regimens. IT may have a crucial impact on the natural history of AI myocarditis, preventing its progression to end-stage heart failure, cardiovascular death, or heart transplantation, provided that strict appropriateness and safety criteria are observed. In particular, AZA treatment for AI virus-negative myocarditis requires the consideration of some crucial aspects regarding its pharmacokinetics and pharmacodynamics, as well as a high index of suspicion to detect its overt and/or subclinical side effects. Importantly, besides a tight teamwork with a clinical immunologist/immuno-rheumatologist, before starting IT, it is also necessary to carry out a careful "safety check-list" in order to rule out possible contraindications to IT and minimize patient's risk. The aim of this review is to describe the pharmacological properties of AZA, as well as to discuss practical aspects of its clinical use, in the light of existing evidence, with particular regard to the new field of cardioimmunology.

Dilated cardiomyopathy and chronic cardiac inflammation: Pathogenesis, diagnosis and therapy

Dilated cardiomyopathy (DCM) is typically defined by left ventricular dilation and systolic dysfunction in the absence of a clear precipitant. Idiopathic disease is common; up to 50% of patients with DCM have no cause found despite imaging, genetic and biopsy assessments. Treatment remains focused on managing symptoms, reducing the risk of sudden cardiac death and ameliorating the structural and electrical complications of disease progression. In the absence of aetiology-specific treatments, the condition remains associated with a poor prognosis; mortality is approximately 40% at 10 years. The role of immune-mediated inflammatory injury in the development and progression of DCM was first proposed over 30 years ago. Despite the subsequent failures of three large clinical trials of immunosuppressive treatment (ATTACH, RENEWAL and the Myocarditis Treatment Trial), evidence for an abnormal adaptive immune response in DCM remains significant. In this review, we summarise and discuss available evidence supporting immune dysfunction in DCM, with a specific focus on cellular immunity. We also highlight current clinical and experimental treatments. We propose that the success of future immunosuppressive treatment trials in DCM will be dependent on the deep immunophenotyping of patients, to identify those with active inflammation and/or an abnormal immune response who are most likely to respond to therapy.

Primary heart involvement in systemic sclerosis, from conventional to innovative targeted therapeutic strategies

Primary heart involvement is frequent in systemic sclerosis, even though often sub-clinical, and includes cardiac abnormalities that are predominantly attributable to systemic sclerosis rather than other causes and/or complications. A timely diagnosis is crucial to promptly start the appropriate therapy and to prevent the potential life-threatening early and late complications. There is little evidence on how to best manage systemic sclerosis-primary heart involvement as no specific treatment recommendations for heart disease are available, and a shared treatment approach is still lacking. The objective of this review is to summarize the state of the art of current literature and the overall management strategies and therapeutic approaches for systemic sclerosis-primary heart involvement. Novel insights into pathogenic mechanisms of systemic sclerosis-primary heart involvement are presented to facilitate the comprehension of therapeutic targets and novel treatment strategies.

Cardiac magnetic resonance imaging before and after therapeutic interventions for systemic sclerosis-associated myocarditis

OBJECTIVES

Cardiac Magnetic Resonance (CMR) imaging is increasingly used to evaluate cardiac involvement in Systemic Sclerosis (SSc). We assessed changes, including inflammatory and/or fibrotic myocardial lesions detected by CMR, following therapeutic interventions for SSc-associated symptomatic myocarditis.

METHODS

In this retrospective study, myocarditis was diagnosed by CMR (2018 revised Lake Louise criteria) in 14 diffuse and 4 limited SSc patients (16/18 women, aged 56 ± 11 years, disease duration 8 ± 11 years, 17/18 with lung involvement) with cardiac symptoms and abnormal findings in echocardiography (4/18) and/or in 24-h Holter monitoring (12/14). CMR was repeated after 8 ± 3 months following administration of cyclophosphamide (n = 11, combined with corticosteroids in 3 and rituximab in 1), mycophenolate (n = 1), tocilizumab (n = 1), methotrexate/corticosteroids (n = 2), corticosteroids (n = 1) or autologous stem cell transplantation (n = 2).

RESULTS

Functional cardiac improvement was evident by increases in left (by 5.8%±7.8%, p= 0.006) and right ventricular ejection fraction (by 4.5%±11.4%, p= 0.085) in the second CMR compared with the first. Notably, Late Gadolinium Enhancement, currently considered to denote replacement fibrosis, decreased by 3.1%±3.8% (p= 0.003), resolving in 6 patients. Markers of myocardial oedema, namely T2-ratio and T2-mapping, decreased by 0.27 ± 0.40 (p= 0.013) and 6.0 ± 7 (p= 0.025), respectively. Conversely, both T1-mapping, considered to reflect acute oedema and diffuse fibrosis, and extracellular volume fraction, reflecting diffuse fibrosis, remained unchanged.

CONCLUSIONS

CMR may distinguish between reversible inflammatory/fibrotic and irreversible fibrotic lesions in SSc patients with active myocarditis, confirming the unique nature of primary cardiac involvement in SSc. Whether, and how, CMR should be used to monitor treatment effects in SSc-associated myocarditis warrants further study.

Combination of Sophora flavescens alkaloids and Panax quinquefolium saponins modulates different stages of experimental autoimmune myocarditis via the NF‑κB and TGF‑β1 pathways

Chronic cardiac inflammation and fibrosis can progress into severe forms of cardiomyopathy. Sophora flavescens alkaloids (KuShen) have been previously reported to exert anti-inflammatory effects, whereas Panax quinquefolium saponins (XiYangShen) has been shown to alleviate cardiac fibrosis. Therefore, the potential effects of their combination (KX) on different stages of autoimmune myocarditis were investigated in the present study. Mice were randomly divided into the following four groups: Control; experimental autoimmune myocarditis (EAM); KX-High (275 mg/kg); and KX-Low (138 mg/kg). A 21-day and a 60-day EAM model was established through multi-site subcutaneous injections of cardiac myosin mixed with complete Freund's adjuvant on days 0, 7, 21 and 42. Mice in the High and Low KX groups were treated by gavage (10 ml/kg) daily from day 0 (1 day before treatment) until sacrifice (day 21 or 60). Mice in the control and EAM groups received an equivalent volume of distilled water. The levels of lactate dehydrogenase (LDH), creatine kinase-myocardial band (CK-MB), cardiac troponin I (cTn-I), IL-1β, IL-6, TNF-α, TGF-β1, collagen type I (Col Ⅰ) and collagen type III (Col Ⅲ) were measured by ELISA in the mouse myocardial tissues or serum. Myocardial tissue structure and extent of fibrosis were visualized using H&E and Masson's staining. Western blotting and immunohistochemistry were used to measure the expression levels NF-κB and TGF-β1 pathway proteins in the myocardial tissues. The degree of inflammation in the 21-day EAM model was found to be significantly higher compared with that in the 60-day EAM model. KX significantly reduced the inflammatory response at 21 days by decreasing the expression levels of CK-MB, LDH, cTn-I, IL-1β, IL-6, TNF-α and TGF-β-activated kinase 1-binding protein 1/NF-κB pathway proteins. Myocardial fibrosis in the 60-day EAM model was also significantly worse compared with that in the 21-day EAM model. However, fibrosis was significantly delayed by treatment with KX. In addition, KX significantly decreased the expression levels of TGF-β1, Smad2, Smad4, Col I and Col III. Therefore, these data suggest that KX is beneficial for treating myocarditis by targeting multiple pathways.

Cardiac magnetic resonance in systemic sclerosis myocarditis: the value of T2 mapping to detect myocardial inflammation

Objectives

Myocarditis in systemic sclerosis (SSc) is associated with a poor prognosis. Cardiac Magnetic Resonance (CMR) is the non-invasive diagnostic modality of choice for SSc-myocarditis. Our study investigates the performance of the mapping techniques, included in the revised Lake Louise Criteria (LLC), for the identification of SSc-myocarditis.

Methods

CMR data (right and left ventricular function and morphology, early and late gadolinium enhancement [LGE], T2 ratio, and T1 mapping, extra-cellular volume [ECV] and T2 mapping) of SSc patients diagnosed with myocarditis were reviewed. Myocarditis was defined by the presence of symptoms of SSc-heart involvement with increased high-sensitive troponin T(hs-TnT) and/or NT-proBNP and at least an abnormality at 24 h-ECG-Holter and/or echocardiography and/or CMR. A p-value < 0.05 was considered as statistically significant.

Results

19 patients (median age 54 [46–70] years; females 78.9%; diffuse SSc 52.6%; anti-Scl70 + 52.6%) were identified: 11(57.9%) had echocardiographic, and 8(42.8%) 24 h-ECG Holter abnormalities. All patients had at least one CMR abnormality: LGE in 18(94.7%), increased ECV in 10(52.6%), T2 mapping > 50ms in 15(78.9%). Median T1 and T2 mapping were 1085[1069–1110]ms and 53.1[52–54]ms, respectively. T1 mapping directly correlated with NT-proBNP(r = 0.620; p= 0.005), ESR(r = 0.601; p= 0.008), CRP(r = 0.685; p= 0.001) and skin score(r = 0.507; p= 0.027); ECV correlated with NT-proBNP serum levels(r = 0.702; p= 0.001). No correlations emerged between T2 mapping and other parameters. Ten patients satisfied the 2009 LLC, 17 the 2018 LLC. With the new criteria including T2-mapping, the sensitivity improved from 52.6% to 89.5%.

Conclusion

the CMR mapping techniques improve the sensitivity to detect myocardial inflammation in patients with SSc-heart involvement. The evaluation of T2 mapping increases diagnostic accuracy for the recognition of myocardial inflammation in SSc.

Heart Involvement in Systemic Sclerosis: the Role of Magnetic Resonance Imaging

Systemic sclerosis (SSc) is a severe connective tissue disease characterized by diffuse vascular damage and aberrant activation of immune system, resulting in inflammation and fibrosis of skin and internal organs, including the heart. Cardiac involvement is frequent in SSc, even though often unrecognized due to the occult nature at early stages and to the lack of a defined diagnostic algorithm. Once clinically evident, heart involvement is associated with a poor prognosis, representing the leading cause of death in about one third of SSc patients. Thus, its early recognition and monitoring are of crucial importance to allow a prompt therapeutic intervention and to improve patients' outcomes. Cardiac Magnetic Resonance (CMR) is a non-invasive, non-radiating imaging technique of great importance for the assessment of cardiovascular system, and represents the modality of choice for the morpho-functional and structural characterization of the heart. In SSc, CMR allows a precise definition of biventricular and biatrial size and function, and a detailed tissue characterization. CMR has been therefore extensively proposed in SSc as a non-invasive diagnostic tool to characterize heart involvement, particularly myocardial involvement. In this review, we summarize the most recent evidences to support the use of CMR in SSc as an important tool to recognize and characterize scleroderma heart disease. Furthermore, the unmet needs and the future perspectives of a CMR-based approach for the early detection of SSc heart involvement are discussed.

Management of myocarditis in clinical practice

Myocarditis is an inflammatory heart muscle disease characterised by heterogeneous clinical presentation and outcome. Clinical heterogeneity of myocarditis, ranging from acute onset chest pain with electrocardiographic changes resembling an acute coronary syndrome, to arrhythmic storm and chronic decompensated heart failure, makes diagnosis challenging. A correct diagnosis is however key to proper patients' management and should always be aimed at. Although a definite diagnosis is only provided by endomyocardial biopsy, the European Society of Cardiology task force on myocardial and pericardial diseases provided specific criteria for the diagnosis of clinically suspected myocarditis, which has been facilitated by the advent of non invasive imaging tests (i.e. cardiovascular magnetic resonance based myocardial tissue characterization). Due to the heterogeneous presentation and disease course of myocarditis, a tailored treatment would be the best strategy, but a standardised management is still not available. Over the years, however, new, promising, therapies, such as anti-viral and immune-suppressive treatment, have come side by side to the standard pharmacological heart treatment, i.e. anti-heart failure medications. In this paper we will review the basic principles of myocarditis management in clinical practice, including diagnostic work-up, conventional and disease-specific therapy and patients' follow-up.

Systemic sclerosis myocarditis has unique clinical, histological and prognostic features: a comparative histological analysis

OBJECTIVE

To outline the clinical, histological and prognostic features of systemic sclerosis (SSc) endomyocardial biopsy-proven myocarditis with respect to those of diverse endomyocardial biopsy-proven virus-negative myocarditis (VNM).

METHODS

We retrospectively analysed data from three cohorts of endomyocardial biopsy-proven myocarditis: SSc-related VNM (SSc-VNM); isolated VNM (i-VNM); and VNM related to other systemic autoimmune diseases (a-VNM). The degree of myocardial fibrosis was expressed as relative percentage and fibrotic score (0-3). Clinical data, cardiac enzymes, echocardiogram, 24 h ECG Holter and cardiac magnetic resonance were obtained at baseline and during follow-up. Non-parametric tests were used.

RESULTS

We enrolled 12 SSc-VNM [11 females, mean age 49.3 (14.2) years; seven diffuse-SSc, five early-SSc], 12 i-VNM [12 females, mean age 47.7 (10.8) years] and 10 a-VNM [four females, mean age 48.4 (16.3) years] patients. SSc patients had higher degrees of myocardial fibrosis as assessed by both percentage [SSc-VNM: 44.8 (18.8)%; a-VNM: 28.6 (16.5)%; i-VNM: 24.9 (10.3)%; P = 0.019] and score [SSc-VNM: 2.3 (0.8); a-VNM: 1.4 (1.1); i-VNM: 1.2 (0.7); P = 0.002]. Myocardial fibrosis directly correlated with skin score (r = 0.625, P = 0.03) and number of ventricular ectopic beats on 24 h ECG Holter in SSc patients (r = 0.756, P = 0.01). Dyspnoea class was higher at presentation in SSc-VNM patients (P = 0.041) and we found heart failure only in SSc patients (25%) (P = 0.05). At cardiac magnetic resonance, myocardial oedema was nearly undetectable in SSc-VNM patients compared with others (P = 0.02). All patients received immunosuppressive treatment. The number of patients who died during follow-up due to cardiac complications was significantly higher in SSc-VNM patients (50%), as compared with a-VNM (0%) and i-VNM (8.3%) patients (P = 0.006). Patients who died during follow-up had higher degrees of myocardial fibrosis [52.2 (11.6)% vs 27.5 (12.9)%, P = 0.024; fibrotic score: 2.83 (0.41) vs 1.4 (0.9), P < 0.001].

CONCLUSION

SSc has unique clinical and histological features, as it tends to present more frequently with heart failure and a higher dyspnoea class and to show higher degrees of myocardial fibrosis. These specific features are paralleled by a worse cardiac prognosis.

Myocarditis and inflammatory cardiomyopathy: current evidence and future directions

Inflammatory cardiomyopathy, characterized by inflammatory cell infiltration into the myocardium and a high risk of deteriorating cardiac function, has a heterogeneous aetiology. Inflammatory cardiomyopathy is predominantly mediated by viral infection, but can also be induced by bacterial, protozoal or fungal infections as well as a wide variety of toxic substances and drugs and systemic immune-mediated diseases. Despite extensive research, inflammatory cardiomyopathy complicated by left ventricular dysfunction, heart failure or arrhythmia is associated with a poor prognosis. At present, the reason why some patients recover without residual myocardial injury whereas others develop dilated cardiomyopathy is unclear. The relative roles of the pathogen, host genomics and environmental factors in disease progression and healing are still under discussion, including which viruses are active inducers and which are only bystanders. As a consequence, treatment strategies are not well established. In this Review, we summarize and evaluate the available evidence on the pathogenesis, diagnosis and treatment of myocarditis and inflammatory cardiomyopathy, with a special focus on virus-induced and virus-associated myocarditis. Furthermore, we identify knowledge gaps, appraise the available experimental models and propose future directions for the field. The current knowledge and open questions regarding the cardiovascular effects associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are also discussed. This Review is the result of scientific cooperation of members of the Heart Failure Association of the ESC, the Heart Failure Society of America and the Japanese Heart Failure Society.

Viral presence-guided immunomodulation in lymphocytic myocarditis: an update

Latest statements from European and American societies recommend to rule out viral presence in endomyocardial biopsy (EMB) via polymerase chain reaction (PCR) analysis before starting immunosuppression or immunomodulation in acute lymphocytic myocarditis presenting with life‐threatening scenarios. However, recommendations in myocarditis are mostly based on heterogeneous studies enrolling patients with inflammatory cardiomyopathies and established heart failure rather than acute myocarditis. Thus, definitive evidence of a survival benefit from immunomodulation guided by viral presence is currently lacking. Finally, distinguishing innocent bystanders from causative agents among EMB‐detected viruses remain challenging and a major goal to achieve in the near future. Therefore, considerable divergence remains between official recommendations and clinical practice, including the possibility of starting immunosuppressive therapy empirically, without knowing viral PCR results. This review systematically discusses the unsolved issues of immunomodulation guided by viral presence in acute lymphocytic myocarditis, namely (i) virus epidemiology and prognosis, (ii) variability of viral presence rates, (iii) the role of potential viral bystander findings, and (iv) the main results of immunosuppression controlled trials in lymphocytic myocarditis. Furthermore, a practical approach for the critical use of viral presence analysis in guiding immunomodulation is provided, highlighting its importance before starting immunosuppression or immunomodulation. Future, multicentre studies are needed to address specific scenarios such as fulminant lymphocytic myocarditis and a virus‐tailored management as for parvovirus B19.

Therapeutic strategies for virus-negative myocarditis: a comprehensive review

Virus-negative or autoimmune myocarditis(VNM) is an inflammatory disease affecting the myocardium that may occur as a distinct disease with exclusive cardiac involvement, or in the context of systemic autoimmune or inflammatory disorders. The pathogenesis of VNM involves both innate and acquired immunity and is not completely elucidated: an early immune-mediated pathogenic process lead to subacute and chronic stages and eventually results in tissue remodeling, fibrosis, contractile dysfunction, dilated cardiomyopathy and arrhythmic burden, accounting for a dismal prognosis. Treatment interventions effectively curbing the acute inflammatory process at an early stage can prevent late cardiac remodeling and improve patient's outcome. The mainstay of treatment of VNM remains symptomatic therapy of heart failure and arrhythmia, while the use of immunosuppressive treatments has long been considered controversial until recently, and strategies effectively targeting the inflammatory and immune-mediated substrate of the disease remain elusive. Only steroids and azathioprine have been tested in clinical trials, and nowadays represent the therapy of choice. A substantial proportion of patients are resistant to first line strategies, suggesting that some critical inflammatory mechanisms are not responsive to conventional immunosuppression with steroids and azathioprine, or experience drug-related adverse events. Thus, second-line targeted therapeutic strategies to treat VNM are eagerly awaited. Recent data on the pathogenic mechanisms underlying myocardial inflammation are paving the way to novel, promising treatment strategies for myocarditis, which could reformulate future treatment strategies for VNM. In this review, we summarize the current therapeutic opportunities, beyond corticosteroids, to treat VNM, including conventional and biologic immunosuppressive drugs and cytokine blocking agents.

Immunosuppressive Therapy and Risk Stratification of Patients With Myocarditis Presenting With Ventricular Arrhythmias

OBJECTIVES

This study sought to investigate the effects of immunosuppression on arrhythmic myocarditis.

BACKGROUND

The effects of immunosuppressive therapy (IST) on ventricular arrhythmia (VA) have not been reported in patients with immune-mediated biopsy-proven myocarditis. Furthermore, myocarditis arrhythmic risk is still unpredictable.

METHODS

We enrolled 255 patients with biopsy-proven virus-negative myocarditis and VA (major: ventricular fibrillation, ventricular tachycardia; minor: nonsustained ventricular tachycardia, Lown grade ≥2 premature ventral complexes) at presentation. Serum cardiac autoantibodies (antiheart antibodies, anti-intercalated disk autoantibodies [AIDA]) were detected by a standardized indirect immunofluorescence technique. Whenever accepted and noncontraindicated, IST was started. Control individuals (IST^-) were chosen after 1:1 matching to IST⁺ patients by age, sex, ethnicity, left ventricular ejection fraction, VA type, and treatment.

RESULTS

A total of 58 matched patient couples (age 42 ± 13 years; 67% male) were analyzed in the main study cohort. IST duration was 12 ± 1 months. By the 24-month prospective follow-up, major VA occurred in 6 IST⁺ versus 10 IST^- patients (p = 0.42), with no episodes following IST termination. As compared to IST^- patients, IST⁺ patients showed a significant reduction in minor VA burden, as well as improvement in clinical, laboratory, and imaging findings (all p < 0.05). Major VA onset and positive AIDA status were independently associated with major VA at follow-up (hazard ratio [HR]: 14.2; 95% confidence interval [CI]: 2.9 to 68.7 and HR: 8.0; 95% CI: 2.6 to 25.2, respectively; both p < 0.001). Furthermore, in the whole study population (N = 255), IST was independently associated with protection from major VA (HR: 0.3; 95% CI: 0.2 to 0.7; p = 0.01) at 38 ± 21 months of follow-up.

CONCLUSIONS

In patients with immune-mediated virus-negative myocarditis presenting with VA, IST is associated with positive effects on minor VA and nonarrhythmic endpoints. Short-term effects are limited on major VA, which were independently associated with major VA onset and positive AIDA.

A Toolbox of Potential Immune-Related Therapies for Inflammatory Cardiomyopathy

Myocarditis is a multifactorial disorder, characterized by an inflammatory reaction in the myocardium, predominantly triggered by infectious agents, but also by antigen mimicry or autoimmunity in susceptible individuals. Unless spontaneously resolved, a chronic inflammatory course concludes with cardiac muscle dysfunction portrayed by ventricular dilatation, clinically termed inflammatory cardiomyopathy (Infl-CM). Treatment strategies aim to resolve chronic inflammation and preserve cardiac function. Beside standard heart failure treatments, which only play a supportive role in this condition, systemic immunosuppressants are used to diminish inflammatory cell function at the cost of noxious side effects. To date, the treatment protocols are expert-based without large clinical evidence. This review describes concept and contemporary strategies to alleviate myocardial inflammation and sheds light on potential inflammatory targets in an evidence-based order.