Ventricular remodeling in active myocarditis. Myocarditis Treatment Trial

Myocarditis and pericarditis: Case definition and guidelines for data collection, analysis, and presentation of immunization safety data

Myocarditis and/or pericarditis (also known as myopericarditis) are inflammatory diseases involving the myocardium (with non-ischemic myocyte necrosis) and/or the pericardial sac. Myocarditis/pericarditis (MPC) may present with variable clinical signs, symptoms, etiologies and outcomes, including acute heart failure, sudden death, and chronic dilated cardiomyopathy. Possible undiagnosed and/or subclinical acute myocarditis, with undefined potential for delayed manifestations, presents further challenges for diagnosing an acute disease and may go undetected in the setting of infection as well as adverse drug/vaccine reactions. The most common causes of MPC are viral, with non-infectious, drug/vaccine associated hypersensitivity and/or autoimmune causes being less well defined and with potentially different inflammatory mechanisms and treatment responses. Potential cardiac adverse events following immunization (AEFIs) encompass a larger scope of diagnoses such as triggering or exacerbating ischemic cardiac events, cardiomyopathy with potential heart failure, arrhythmias and sudden death. The current published experience does not support a potential causal association with vaccines based on epidemiologic evidence of relative risk increases compared with background unvaccinated incidence. The only evidence supporting a possible causal association of MPC with a vaccine comes from case reports. Hypersensitivity MPC as a drug/vaccine induced cardiac adverse event has long been a concern for post-licensure safety surveillance, as well as safety data submission for licensure. Other cardiac adverse events, such as dilated cardiomyopathy, were also defined in the CDC definitions for adverse events after smallpox vaccination in 2006. In addition, several groups have attempted to develop and improve the definition and adjudication of post-vaccination cardiovascular events. We developed the current case definitions for myocarditis and pericarditis as an AEFI building on experience and lessons learnt, as well as a comprehensive literature review. Considerations of other etiologies and causal relationships are outside the scope of this document.

Acute Myocarditis in Children: An Overview of Treatment and Recent Patents

BACKGROUND

Pediatric myocarditis is rare but challenging. This overview summarized the current knowledge and recent patents on childhood myocarditis.

METHODS

Clinical queries and keywords of "myocarditis" and "childhood" were used as search engine.

RESULTS

Viral infections are the most common causes of acute myocarditis. Affected children often have a prodrome of fever, malaise, and myalgia. Clinical manifestations of acute myocarditis in children can be nonspecific. Some children may present with easy fatigability, poor appetite, vomiting, abdominal pain, exercise intolerance, respiratory distress/tachypnea, dyspnea at rest, orthopnea, chronic cough with wheezing, chest pain, unexplained tachycardia, hypotension, syncope, and hepatomegaly. Supraventricular arrhythmias, ventricular arrhythmias, and heart block may be present. A subset of patients have fulminant myocarditis and present with cardiovascular collapse, which may progress to severe cardiogenic shock, and even death. A high index of suspicion is crucial to its diagnosis and timely management. Cardiac magnetic resonance imaging is important in aiding clinical diagnosis while, endomyocardial biopsy remains the gold standard. The treatment consists of supportive therapy, ranging from supplemental oxygen and fluid restriction to mechanical circulatory support. Angiotensinconverting enzyme inhibitors, angio-tensin II receptor blockers, β-blockers, and aldosterone antagonists might be used for the treatment of heart failure while, immunosuppression treatments remain controversial. There are a few recent patents targeting prevention or treatment of viral myocarditis, including an immunogenic composition comprising a PCV-2 antigen, glutathione-S-transferase P1, neuregulins, NF-[kappa] B inhibitor, a pharmaceutical composition which contains 2-amino-2- (2- (4-octyl phenyl) - ethyl) propane 1,3-diol, a composition containing pycnojenol, Chinese herbal concoctions, and a Korean oral rapamycin. Evidence of their efficacy is still lacking.

CONCLUSION

This article reviews the current literature regarding etiology, clinical manifestations, diagnosis, and management of acute myocarditis in children.

Myocarditis in the Setting of Cancer Therapeutics: Proposed Case Definitions for Emerging Clinical Syndromes in Cardio-Oncology

Recent developments in cancer therapeutics have improved outcomes but have also been associated with cardiovascular complications. Therapies harnessing the immune system have been associated with an immune-mediated myocardial injury described as myocarditis. Immune checkpoint inhibitors are one such therapy with an increasing number of case and cohort reports describing a clinical syndrome of immune checkpoint inhibitor–associated myocarditis. Although the full spectrum of immune checkpoint inhibitor–associated cardiovascular disease still needs to be fully defined, described cases of myocarditis range from syndromes with mild signs and symptoms to fatal events. These observations in the clinical setting stand in contrast to outcomes from randomized clinical trials in which myocarditis is a rare event that is investigator reported and lacking in a specific case definition. The complexities associated with diagnosis, as well as the heterogeneous clinical presentation of immune checkpoint inhibitor–associated myocarditis, have made ascertainment and identification of myocarditis with high specificity challenging in clinical trials and other data sets, limiting the ability to better understand the incidence, outcomes, and predictors of these rare events. Therefore, establishing a uniform definition of myocarditis for application in clinical trials of cancer immunotherapies will enable greater understanding of these events. We propose an operational definition of cancer therapy-associated myocarditis that may facilitate case ascertainment and report and therefore may enhance the understanding of the incidence, outcomes, and risk factors of this novel clinical syndrome.

Imaging-Specific Cardiomyopathies: A Practical Guide

Heart failure is a clinical syndrome with a broad spectrum of presentations. Cardiovascular imaging techniques such as echocardiography, cardiovascular magnetic resonance, computed tomography, and nuclear imaging play a crucial role in diagnosis, guiding management, and providing prognostic information. Each of these imaging modalities has their own respective strengths and weaknesses. Cardiac imaging can help differentiate between ischemic and nonischemic cardiomyopathies. Additionally, imaging techniques can display disease-specific findings, aiding in diagnosis of nonischemic cardiomyopathies and can provide a means to monitor response to therapy. The choice of imaging modality in the workup of cardiomyopathy should be based on the specific clinical question and the knowledge of the strengths and limitations of each imaging modality.

Noninvasive Contrast-Enhanced Ultrasound Molecular Imaging Detects Myocardial Inflammatory Response in Autoimmune Myocarditis

Background—

Cardiac tests for diagnosing myocarditis lack sensitivity or specificity. We hypothesized that contrast-enhanced ultrasound molecular imaging could detect myocardial inflammation and the recruitment of specific cellular subsets of the inflammatory response in murine myocarditis.

Methods and Results—

Microbubbles (MB) bearing antibodies targeting lymphocyte CD4 (MB CD4 ), endothelial P-selectin (MB PSel ), or isotype control antibody (MB Iso ) and MB with a negative electric charge for targeting of leukocytes (MB Lc ) were prepared. Attachment of MB CD4 was validated in vitro using murine spleen CD4+ T cells. Twenty-eight mice were studied after the induction of autoimmune myocarditis by immunization with α-myosin-peptide; 20 mice served as controls. Contrast-enhanced ultrasound molecular imaging of the heart was performed. Left ventricular function was assessed by conventional and deformation echocardiography, and myocarditis severity graded on histology. Animals were grouped into no myocarditis, moderate myocarditis, and severe myocarditis. In vitro, attachment of MB CD4 to CD4+ T cells was significantly greater than of MB Iso . Of the left ventricular ejection fraction or strain and strain rate readouts, only longitudinal strain was significantly different from control animals in severe myocarditis. In contrast, contrast-enhanced ultrasound molecular imaging showed increased signals for all targeted MB versus MB Iso both in moderate and severe myocarditis, and MB CD4 signal correlated with CD4+ T-lymphocyte infiltration in the myocardium.

Conclusions—

Contrast-enhanced ultrasound molecular imaging can detect endothelial inflammation and leukocyte infiltration in myocarditis in the absence of a detectable decline in left ventricular performance by functional imaging. In particular, imaging of CD4+ T cells involved in autoimmune responses could be helpful in diagnosing myocarditis.

Myocarditis

Viral myocarditis remains a prominent infectious-inflammatory disease for patients throughout the lifespan. The condition presents several challenges including varied modes of clinical presentation, a range of timepoints when patients come to attention, a diversity of approaches to diagnosis, a spectrum of clinical courses, and unsettled perspectives on therapeutics in different patient settings and in the face of different viral pathogens. In this review, we examine current knowledge about viral heart disease and especially provide information on evolving understanding of mechanisms of disease and efforts by investigators to identify and evaluate potential therapeutic avenues for intervention.

Injectable collagen implant improves survival, cardiac remodeling, and function in the early period after myocarditis in rats

AIM

Despite clear evidence of immune system involvement in the pathogenesis of myocarditis, the treatment of myocarditis remains nonspecific and supportive. We sought to test the hypothesis that injection of a collagen-based implant into the inflamed myocardium would stabilize the left ventricular (LV) wall and prevent adverse remodeling and dysfunction.

METHODS AND RESULTS

Autoimmune myocarditis was induced in 42 male Lewis rats. Development of myocarditis was evaluated and confirmed by serial echocardiography and cardiac magnetic resonance scans, LV wall thickening, global and regional LV wall motion abnormalities, and in some cases pericardial effusion. Sick animals were randomized to either injectable collagen implantation or saline injection into the anterior inflamed myocardium 14 days after immunization. Significantly, injectable collagen implantation improved 31-day survival compared with controls (85.7% vs 50%; P = .03). Furthermore, although injectable collagen significantly attenuated LV systolic and diastolic dilatation and preserved LV geometry and function, control animals developed significant LV dilatation and dysfunction. These favorable effects on LV remodeling were confirmed by postmortem morphometry. Significantly, the injectable collagen implant attenuated cardiomyocyte hypertrophy and infiltration of macrophages and lymphocytes into the myocardium.

CONCLUSIONS

The present study shows, for the first time, that injectable collagen biomaterial improves survival and attenuates cardiac inflammation, cardiomyocyte hypertrophy, LV remodeling, and dysfunction in the early period after myocarditis in rats. Our findings suggest a new biomaterial-based strategy to ameliorate the devastating effects of myocarditis.

Diagnosis and treatment of viral myocarditis

Myocarditis, an inflammatory disease of heart muscle, is an important cause of dilated cardiomyopathy worldwide. Viral infection is also an important cause of myocarditis, and the spectrum of viruses known to cause myocarditis has changed in the past 2 decades. Several new diagnostic methods, such as cardiac magnetic resonance imaging, are useful for diagnosing myocarditis. Endomyocardial biopsy may be used for patients with acute dilated cardiomyopathy associated with hemodynamic compromise, those with life-threatening arrhythmia, and those whose condition does not respond to conventional supportive therapy. Important prognostic variables include the degree of left and right ventricular dysfunction, heart block, and specific histopathological forms of myocarditis. We review diagnostic and therapeutic strategies for the treatment of viral myocarditis. English-language publications in PubMed and references from relevant articles published between January 1, 1985, and August 5, 2008, were analyzed. Main keywords searched were myocarditis, dilated cardiomyopathy, endomyocardial biopsy, cardiac magnetic resonance imaging, and immunotherapy.

Rapid Recovery from Acute, Potentially Lethal Myocarditis

Two cases of acute myocarditis in young men, both with clinical and laboratory criteria indicating poor prognosis, were initially treated with conventional treatment (captopril plus metoprolol). The addition of intravenous immunoglobulin was followed by rapid clinical and laboratory recovery. This observation is considered to support previous but ambiguous evidence that autoimmune treatment may help recovery from acute myocarditis that has evidence of poor prognosis.

Myocarditis

Myocarditis may present with a wide range of symptoms, ranging from mild dyspnea or chest pain that resolves without specific therapy to cardiogenic shock and death. Dilated cardiomyopathy with chronic heart failure is the major long-term sequela of myocarditis. Most often, myocarditis results from common viral infections; less commonly, specific forms of myocarditis may result from other pathogens, toxic or hypersensitivity drug reactions, giant-cell myocarditis, or sarcoidosis. The prognosis and treatment of myocarditis vary according to the cause, and clinical and hemodynamic data usually provide guidance to decide when to refer a patient to a specialist for endomyocardial biopsy. The aim of this review is to provide a practical and current approach to the evaluation and treatment of suspected myocarditis.

Cardiac involvement after respiratory tract viral infection--detection by cardiac magnetic resonance

OBJECTIVE

The purpose of our study was to investigate whether cardiovascular magnetic resonance imaging can detect early myocardial tissue edema as a first step in the development of myocarditis.

METHODS

We examined 36 consecutive patients who were presented with symptoms of fatigue, weakness, and/or palpitations after respiratory tract infection but normal left ventricular function and compared these patients with 21 consecutive controls without acute symptoms. Electrocardiogram-triggered, T2-weighted, fast spin echo triple-inversion recovery sequences were performed in all patients.

RESULTS

We found a significant difference between patients with suspected myocarditis and controls in global myocardial signal intensity. The ratio of global myocardial signal intensity/muscle signal intensity was 2.4 +/- 0.3 in patients and 1.9 +/- 0.3 in controls, which was highly significant (P < 0.001).

CONCLUSIONS

Patients with symptoms of fatigue, weakness, and/or palpitations after respiratory tract infection showed an elevated signal intensity of the myocardium, indicating edematous tissue, which may be the first step in the development of myocarditis.

Coronary flow reserve in idiopathic dilated cardiomyopathy: relation with left ventricular wall stress, natriuretic peptides, and endothelial dysfunction

Studies have demonstrated impaired coronary blood flow reserve (CBFR) in idiopathic dilated cardiomyopathy (IDCM). It was the aim of this study to examine the potential underlying mechanisms for CBFR reduction in patients with IDCM by Doppler ultrasound techniques. Forty-eight clinically stable patients with heart failure caused by IDCM (New York Heart Association classes 1-3) were evaluated by echocardiographic and Doppler techniques with the assessments of CBFR and brachial artery flow-mediated dilation (FMD). CBFR was estimated as the hyperemic (dipyridamole: 0.84 mg/kg in 10 minutes, intravenously) to resting coronary diastolic peak velocities ratio. N-terminal pro-brain natriuretic peptide (Nt-pro-BNP) plasma levels were measured at the time of the index echocardiogram. Left ventricular (LV) ejection fraction was 30% +/- 8%, and wall motion score index was 2.0 +/- 0.25. The best correlation with CBFR was found with LV wall thickness-to-cavity radius (r = 0.77, P < .0001). A strong correlation of log-transformed Nt-pro-BNP levels was observed with CBFR (r = -0.64; P < .0001). No significant correlation was documented between CBFR and FMD. The stepwise regression model showed that LV wall thickness-to-cavity radius was the strongest independent predictor of CBFR followed by New York Heart Association class and log-transformed Nt-pro-BNP leading to a cumulative R value of 0.82 (P < .0001). The results of the study indicate that by measuring variables related to LV end-diastolic wall stress, such as LV wall thickness-to-cavity radius and plasma Nt-proBNP, it is possible to have information about CBFR in patients with heart failure secondary to IDCM.

Active bacterial myocarditis: a case report and review of the literature

Bacterial myocarditis (BM) is an uncommon cause of infectious myocarditis. BM is usually seen in the context of overwhelming sepsis or as part of a specific bacterial syndrome. The definitive diagnosis of bacterial myocarditis requires biopsy or morphologically proven active myocarditis with evidence of bacterial invasion or positive tissue cultures. The management of bacterial myocarditis consists of aggressive and early antibiotic or anti-toxin treatment, appropriate hemodynamic support, and treatment of arrhythmias or mechanical complications. We present a case of acute Listeria monocytogenes myocarditis in an immunocompetent patient and highlight the challenges in the diagnosis and treatment of bacterial myocarditis.

Noninvasive imaging in myocarditis

Increased recognition of the role of inflammation in acute and chronic dilated cardiomyopathy has revived an interest in noninvasive imaging for detection of myocarditis. Diagnostic strategies that are based on molecular imaging promise to further advance our understanding and improve diagnostic precision. This article reviews the strengths and limitations of common clinical tests used for the diagnosis of myocarditis, with a focus on the emerging role of cardiovascular magnetic resonance imaging. Novel imaging modalities that are currently in preclinical development are discussed with recommendations for future clinical research.

Ventricular remodeling in children with left ventricular dysfunction secondary to various cardiomyopathies

The ventricular remodeling that occurs in adults with left ventricular (LV) dysfunction is characterized by a change in LV shape from an ellipse to more of a sphere and is associated with increased functional mitral regurgitation (MR), decreased exercise tolerance, and poor outcome. There are limited data on the occurrence and importance of LV remodeling in children with LV dysfunction. The purposes of this study were to evaluate in children with LV dysfunction (1) LV shape, (2) changes in LV shape as LV function improves, and (3) the relation between LV shape and functional MR. Children with LV dysfunction were identified and compared with controls. Patient demographics, treatment, and outcomes were noted. Echocardiograms were reviewed for LV function and shape (sphericity index). The echos of a subset of children whose LV ejection fractions (LVEFs) increased by >10% over a follow-up of >6 months were analyzed for changes in sphericity, mitral annulus size, and the degree of MR. Twenty-five children with LV dysfunction were compared with 37 age-matched controls. LV remodeling to a more spherical shape was inversely related to LVEF but was not associated with clinical outcome. In a subset of patients (n = 17) whose LVEFs improved, the reversal of remodeling (decrease in sphericity index) was associated with a decrease in MR and mitral annulus size. In conclusion, LV remodeling occurs in children with LV dysfunction. The reversal of this remodeling with a decrease in the degree of MR and the size of the mitral annulus occurs as systolic function improves.

Coxsackievirus group B type 3 infection upregulates expression of monocyte chemoattractant protein 1 in cardiac myocytes, which leads to enhanced migration of mononuclear cells in viral myocarditis

Coxsackievirus group B type 3 (CVB3) is an important cause of viral myocarditis. The infiltration of mononuclear cells into the myocardial tissue is one of the key events in viral myocarditis. Immediately after CVB3 infects the heart, the expression of chemokine(s) by infected myocardial cells may be the first trigger for inflammatory infiltration and immune response. However, it is unknown whether CVB3 can induce the chemokine expression in cardiac myocytes. Monocyte chemoattractant protein 1 (MCP-1) is a potent chemokine that stimulates the migration of mononuclear cells. The objective of the present study was to investigate the effect of CVB3 infection on MCP-1 expression in murine cardiac myocytes and the role of MCP-1 in migration of mononuclear cells in viral myocarditis. Our results showed that the expression of MCP-1 was significantly increased in cardiac myocytes after wild-type CVB3 infection in a time- and dose-dependent manner, which resulted in enhanced migration of mononuclear cells in mice with viral myocarditis. The migration of mononuclear cells was partially abolished by antibodies specific for MCP-1 in vivo and in vitro. Administration of anti-MCP-1 antibody prevented infiltration of mononuclear cells bearing the MCP-1 receptor CCR2 in mice with viral myocarditis. Infection by UV-irradiated CVB3 induced rapid and transient expression of MCP-1 in cardiac myocytes. In conclusion, our results indicate that CVB3 infection stimulates the expression of MCP-1 in myocardial cells, which subsequently leads to migration of mononuclear cells in viral myocarditis.

Long-Term Prognosis of Fulminant Myocarditis Rescued by Percutaneous Cardiopulmonary Support Device

BACKGROUND

The long-term prognosis and cardiac function of fulminant myocarditis treated with percutaneous cardiopulmonary support (PCPS) was compared with the outcome of those not treated with PCPS.

METHODS AND RESULTS

From 1991 to 2000, 14 patients with fulminant myocarditis (left ventricle ejection fraction (LVEF) < or =40%) were admitted to hospital. PCPS was necessary for treatment of shock in 8 (PCPS group), but not for the remaining 6 patients (non-PCPS group). In the PCPS group, 6 patients (75%) survived the critical phase and did not have any cardiac problems after discharge (range of follow-up period, 1.4-6.0 years). All patients in the non-PCPS group survived the acute phase; 1 patient had congestive heart failure 1.5 years after discharge, and another died from malignancy (follow-up period range, 2.2-9.4 years). Although the left ventricular ejection fraction (LVEF) of the PCPS group was significantly lower than that of the non-PCPS group in the acute phase, there was no significant difference in LVEF between the 2 groups in the chronic phase.

CONCLUSION

Patients who survive the acute phase crisis of acute myocarditis have a favorable long-term survival rate, whether or not mechanical support is used.

Echocardiographic predictors of survival and response to early revascularization in cardiogenic shock

BACKGROUND

Although echocardiography is used in diagnosis and management of myocardial infarction, it has not been established whether specific features of cardiac structure or function early in the course of cardiogenic shock provide prognostic value. The purposes of this substudy of the SHould we emergently revascularize Occluded Coronaries for cardiogenic shocK (SHOCK) trial were to describe the echocardiographic features of cardiogenic shock, identify findings on early echocardiograms associated with outcome, examine the interaction of such features with treatment, and determine whether these features could provide insights into the survival benefit observed with early revascularization and guide selection of patients for this strategy.

METHODS AND RESULTS

One hundred seventy-five echocardiograms performed within 24 hours of randomization to the early revascularization (ERV) or initial medical stabilization (IMS) arms of the trial were submitted for quantitative assessment, and 169 were suitable for analysis. The 2 groups were similar in terms of clinical and early echocardiographic characteristics. Mean left ventricular ejection fraction (LVEF) was 31%, and moderate or greater mitral regurgitation (MR) was noted in 39.1%. On multivariate analysis, the only independent predictors of survival were MR severity and LVEF. A survival benefit for the ERV strategy was observed at all levels of LVEF and MR.

CONCLUSIONS

A wide range of cardiac structural and functional abnormalities exists in patients presenting with acute cardiogenic shock. Both short- and long-term mortality appear to be associated with initial left ventricular systolic function and MR as assessed by echocardiography, and a benefit of ERV is noted regardless of baseline LVEF or MR.

High-dose intravenous immunoglobulin in the treatment of acute myocarditis. A case report and review of the literature

A few reports have suggested the beneficial effect of high-dose intravenous immunoglobulin (IVIG) in the treatment of acute myocarditis and cardiomyopathy. We describe a 49-year-old woman in which acute myocarditis was diagnosed on the basis of clinical and echocardiographic findings. Conventional treatment with captopril and frusemide was administered: intravenous heparin and, subsequently, oral anticoagulants were added because of the appearance of an apical thrombus. On the fifth day of hospitalization, treatment with high-dose (400 mg kg(-1) day(-1)) IVIG was started and prosecuted for 5 days. A dramatic improvement of clinical conditions was observed, with increase of the left ventricular ejection fraction (LVEF) from 30% to 75% within 1 week. One year after the diagnosis the patient is in good health, with steady normal LVEF. The rapid recovery, which was immediately subsequent to the administration of high-dose IVIG, suggests that this kind of treatment has been effective in our patient with acute myocarditis.

The group B coxsackieviruses and myocarditis

The six serotypes of the group B coxsackieviruses (CVB) are common human enteroviruses linked etiologically to inflammatory cardiomyopathies. This has been demonstrated by molecular detection of enteroviral RNA in human heart tissue, serologic associations with disease, and virus isolation from cases of fulminant myocarditis. The murine model of CVB-associated myocarditis has demonstrated that CVB can be attenuated through mutations at different genomic sites. Human CVB3 isolates demonstrate varying degrees of cardiovirulence in the murine model; one site of virulence determination has been mapped to domain II of the 5' non-translated region. The interplay of CVB replication and the immune response to that replication in the heart is a complex interaction determining the extent to which the virus replication is limited and the degree to which a pathogenic inflammation of cardiac muscle occurs. Studies of CVB3-induced myocarditis in murine strains lacking subsets of the immune system or genes regulating the immune response have demonstrated a pivotal role of the T cell response to the generation of myocarditis. While CVB are associated with 20-25% of cases of myocarditis or cardiomyopathy, the severity of the disease and the existence of attenuated strains shown to generate protective immunity in animal models indicates that vaccination against the CVBs would be valuable.