Combined immunosuppression for the treatment of idiopathic giant cell myocarditis

Systemic Diseases and Heart Block

Systemic diseases can cause heart block owing to the involvement of the myocardium and thereby the conduction system. Younger patients (<60) with heart block should be evaluated for an underlying systemic disease. These disorders are classified into infiltrative, rheumatologic, endocrine, and hereditary neuromuscular degenerative diseases. Cardiac amyloidosis owing to amyloid fibrils and cardiac sarcoidosis owing to noncaseating granulomas can infiltrate the conduction system leading to heart block. Accelerated atherosclerosis, vasculitis, myocarditis, and interstitial inflammation contribute to heart block in rheumatologic disorders. Myotonic, Becker, and Duchenne muscular dystrophies are neuromuscular diseases involving the myocardium skeletal muscles and can cause heart block.

Systemic Diseases and Heart Block

Systemic diseases can cause heart block owing to the involvement of the myocardium and thereby the conduction system. Younger patients (<60) with heart block should be evaluated for an underlying systemic disease. These disorders are classified into infiltrative, rheumatologic, endocrine, and hereditary neuromuscular degenerative diseases. Cardiac amyloidosis owing to amyloid fibrils and cardiac sarcoidosis owing to noncaseating granulomas can infiltrate the conduction system leading to heart block. Accelerated atherosclerosis, vasculitis, myocarditis, and interstitial inflammation contribute to heart block in rheumatologic disorders. Myotonic, Becker, and Duchenne muscular dystrophies are neuromuscular diseases involving the myocardium skeletal muscles and can cause heart block.

Different reverse remodelling between left ventricle and right ventricle in fulminant heart failure due to giant cell myocarditis: a case report

Background

Giant cell myocarditis (GCM) is a rare cause of fulminant heart failure (HF). The most common presentation is progressive hemodynamic deterioration, and a few cases present with idiopathic complete atrioventricular block (cAVB). The prognosis of GCM is poor, and GCM patients usually die of HF and ventricular arrhythmia unless cardiac transplantation is performed. Few reports have described the effects of treatments such as immunosuppression and detailed reverse remodelling in GCM patients.

Case summary

A 69-year-old female presented with cAVB. Transvenous pacemaker was implanted via the left subclavian vein. One and a half months later, she exhibited left ventricular dyssynchrony and lower left ventricular ejection fraction (LVEF), resulting in hospitalization for HF. She received cardiac resynchronization therapy; however, this had no apparently positive effects on her cardiac function. To investigate the cause of the lower LVEF, an endomyocardial biopsy was taken from the right ventricular septum. She was diagnosed with GCM and immediately received immunosuppression therapy with prednisolone and ciclosporin. This resulted in the functional recovery of the right ventricle; on the other hand, the left ventricle had still not recovered based on transthoracic echocardiography. Fortunately, she successfully recovered from severe HF without recurrence.

Discussion

This is a case of fulminant HF due to GCM which initially presented as cAVB. Moreover, this case demonstrates the quite difference of the functional recovery between the left ventricle and the right ventricle with immunosuppression therapy.

Giant cell myositis and myocarditis revisited

Giant cell myositis (GCMm) and giant cell myocarditis (GCMc) are two rare autoimmune conditions. Among these, GCMc is a life-threatening disease with a 1-year mortality rate of 70%. Lethal ventricular arrhythmias, rapid evolution to heart failure and sudden death risk makes GCMc an emergency condition. It is thought to be mediated by T-cells and characterized by the presence of myofiber necrosis and giant cells in biopsies. Most commonly co-manifesting conditions with GCMm and/or GCMc are thymoma, myasthenia gravis and orbital myositis, all of which are treatable. As suspicion is the key approach in diagnosis, the physician following patients with thymoma with or without myasthenia gravis and with orbital myositis should always be alert. The fatal nature of GCMc associated with these relatively benign diseases deserves a special emergency attention with prompt institution of combined immunosuppressive treatment and very early inclusion of heart failure teams.

Evaluation of Myocardial Gene Expression Profiling for Superior Diagnosis of Idiopathic Giant-Cell Myocarditis and Clinical Feasibility in a Large Cohort of Patients with Acute Cardiac Decompensation

Aims: The diagnostic approach to idiopathic giant-cell myocarditis (IGCM) is based on identifying various patterns of inflammatory cell infiltration and multinucleated giant cells (GCs) in histologic sections taken from endomyocardial biopsies (EMBs). The sampling error for detecting focally located GCs by histopathology is high, however. The aim of this study was to demonstrate the feasibility of gene profiling as a new diagnostic method in clinical practice, namely in a large cohort of patients suffering from acute cardiac decompensation. Methods and Results: In this retrospective multicenter study, EMBs taken from n = 427 patients with clinically acute cardiac decompensation and suspected acute myocarditis were screened (mean age: 47.03 ± 15.69 years). In each patient, the EMBs were analyzed on the basis of histology, immunohistology, molecular virology, and gene-expression profiling. Out of the total of n = 427 patient samples examined, GCs could be detected in 26 cases (6.1%) by histology. An established myocardial gene profile consisting of 27 genes was revealed; this was narrowed down to a specified profile of five genes (CPT1, CCL20, CCR5, CCR6, TLR8) which serve to identify histologically proven IGCM with high specificity in 25 of the 26 patients (96.2%). Once this newly established profiling approach was applied to the remaining patient samples, an additional n = 31 patients (7.3%) could be identified as having IGCM without any histologic proof of myocardial GCs. In a subgroup analysis, patients diagnosed with IGCM using this gene profiling respond in a similar fashion to immunosuppressive therapy as patients diagnosed with IGCM by conventional histology alone. Conclusions: Myocardial gene-expression profiling is a promising new method in clinical practice, one which can predict IGCM even in the absence of any direct histologic proof of GCs in EMB sections. Gene profiling is of great clinical relevance in terms of (a) overcoming the sampling error associated with purely histologic examinations and (b) monitoring the effectiveness of therapy.

Recognition and Initial Management of Fulminant Myocarditis: A Scientific Statement From the American Heart Association

Fulminant myocarditis (FM) is an uncommon syndrome characterized by sudden and severe diffuse cardiac inflammation often leading to death resulting from cardiogenic shock, ventricular arrhythmias, or multiorgan system failure. Historically, FM was almost exclusively diagnosed at autopsy. By definition, all patients with FM will need some form of inotropic or mechanical circulatory support to maintain end-organ perfusion until transplantation or recovery. Specific subtypes of FM may respond to immunomodulatory therapy in addition to guideline-directed medical care. Despite the increasing availability of circulatory support, orthotopic heart transplantation, and disease-specific treatments, patients with FM experience significant morbidity and mortality as a result of a delay in diagnosis and initiation of circulatory support and lack of appropriately trained specialists to manage the condition. This scientific statement outlines the resources necessary to manage the spectrum of FM, including extracorporeal life support, percutaneous and durable ventricular assist devices, transplantation capabilities, and specialists in advanced heart failure, cardiothoracic surgery, cardiac pathology, immunology, and infectious disease. Education of frontline providers who are most likely to encounter FM first is essential to increase timely access to appropriately resourced facilities, to prevent multiorgan system failure, and to tailor disease-specific therapy as early as possible in the disease process.

Monomorphic Ventricular Tachycardia as a Presentation of Giant Cell Myocarditis

Background

Idiopathic giant cell myocarditis (GCM) has a fulminant course and typically presents in middle-aged adults with acute heart failure or ventricular arrhythmia. It is a rare disorder which involves T lymphocyte-mediated myocardial inflammation. Diagnosis is challenging and requires a high index of suspicion since therapy may improve an otherwise uniformly fatal prognosis.

Case Summary

A previously healthy 54-year-old female presented with hemodynamically significant ventricular arrhythmia (VA) and was found to have severe left ventricular dysfunction. Cardiac MRI demonstrated acute myocarditis, and endomyocardial biopsy showed giant cell myocarditis. She was treated with combined immunosuppressive therapy as well as guideline-directed medical therapy. A secondary prevention implantable cardioverter defibrillator (ICD) was implanted.

Discussion

GCM is a rare, lethal myocarditis subtype but is potentially treatable. Combined immunosuppression may achieve partial clinical remission in two-thirds of patients. VA is common, and patients should undergo ICD implantation. More research is needed to better understand this complex disease.

Learning Objectives

Giant cell myocarditis is an incompletely understood, rare cause of myocarditis. Patients present predominately with heart failure and dysrhythmia. Diagnosis is confirmed by histopathology, and immunosuppression may improve outcomes. ICD implantation should be considered. In the absence of treatment, prognosis is poor with a median survival of three months.

Cardiac Autoimmunity: Myocarditis

Myocarditis is the inflammation of the muscle tissues of the heart (myocardium). After a pathologic cardiac-specific inflammatory process, it may progress to chronic damage and dilated cardiomyopathy. The latter is characterized by systolic dysfunction, whose clinical correlate is heart failure. Nevertheless, other acute complications may arise as consequence of tissue damage and electrophysiologic disturbances. Different etiologies are involved in triggering myocarditis. In some cases, such as giant cell myocarditis or eosinophilic necrotizing myocarditis, it is an autoimmune process. Several factors predispose the development of autoimmune myocarditis such as systemic/local primary autoimmunity, viral infection, HLA and gender bias, exposure of cryptic antigens, mimicry, and deficient thymic training/Treg induction. Once the anti-myocardium autoimmune process is triggered, several components of the immune response orchestrate a sustained attack toward myocardial tissues with particular timing and immunopathogenic features. Innate response mediated by monocytes/macrophages, neutrophils, and eosinophils parallels the adaptive response, playing a final effector role and not only a priming function. Stromal cells like fibroblast are also involved in the process through specific cytokines. Furthermore, adaptive T cell responses have anti-paradigmatic features, as Th17 response is dispensable for acute myocarditis but is the main driver of the process leading to dilated cardiomyopathy. Humoral response, thought to be a bystander, is important in the appearance of late-stage hemodynamic complications. The complexity of that process, as well as the unspecific and variable clinical presentation, had generated difficulties for diagnosis and treatment, which remain suboptimal. In this chapter, we will discuss the most relevant immunopathogenic findings from a basic science and clinical perspective.

A case of a giant cell myocarditis that developed massive left ventricular thrombus during percutaneous cardiopulmonary support

Background

Giant cell myocarditis, characterized by infiltration of multinucleated giant cells in the myocardium, is a rare type of myocarditis. It often progresses rapidly into fulminant heart failure and indicates a poor prognosis. When a patient with giant cell myocarditis develops into severe myocarditis presenting with a cardiogenic shock, we should use a percutaneous cardiopulmonary support (PCPS), which could occur complications. We experienced a patient with giant cell myocarditis, who developed left ventricular thrombus formations during the circulation support therapy with PCPS for cardiogenic shock.

Case presentation

A 60-year-old man who developed a cardiogenic shock was transferred to our hospital. After the admission, inotropic agents were increased and an intra-aortic balloon pumping was started. But these therapies did not improve his hemodynamic status. He was placed PCPS. Then, he underwent endomyocardial biopsy and was diagnosed with giant cell myocarditis. On the next morning, he developed complete atrioventricular block, and subsequently, thrombus formations occurred in his left ventricular outlet tract and Valsalva sinus despite an anticoagulant therapy. Thereafter, we intensified the anticoagulant therapy to prevent further thrombus formation, but he developed an intracranial hemorrhage. He did not recover from heart failure and died 16 days after the admission.

Conclusions

We present a patient with giant cell myocarditis who developed widespread thrombosis in the left ventricle during the circulatory support with PCPS, despite anticoagulant therapy. In this case, decreased left myocardial contractility caused by giant cell myocarditis and increased left ventricular afterload by the retrograde perfusion from the PCPS induced the thrombotic tendency and congestion in the left ventricle. In addition, he developed complete atrioventricular block, which reduced the left ventricular ejection and enhanced the thrombus formation. Because patients with giant cell myocarditis have a low probability of spontaneous recovery, heart transplantation or ventricular assist device implantation may be required for circulatory support. We should establish mechanical circulatory support rapidly to improve the prognosis of patients with giant cell myocarditis. Moreover, a ventricular assist device, which can prevent both ventricular congestion and retrograde blood flow, might be suitable to prevent complications as this case.

Established and novel treatment options in acute myocarditis, with or without heart failure

INTRODUCTION

Acute myocarditis is a disorder characterized by an unpredictable clinical course which ranges from asymptomatic, incidentally discovered forms, to cases with fulminant course and adverse outcome. The most challenging issues in the context of acute myocarditis are the appearance of difficult to treat heart failure in the acute phase and the potential progression in the long-term to dilated cardiomyopathy. Areas covered: With respect to available treatment options in acute myocarditis, in the absence of specific guidelines, management is supportive and overall empirical, especially for the oligo- or asymptomatic patients with preserved ejection fraction. Haemodynamically instable patients should be treated in referral centers with capability of advanced cardiopulmonary support. Patients with heart failure but without haemodynamic impairment should be treated according to the heart failure guidelines. Endomyocardial biopsy may be performed in an individualized basis both for diagnostic purposes and to guide treatment, based on the detection or not of viral genome. Expert commentary: Apart from the already established treatments, novel therapies against several targets are currently investigated and are expected to contribute to a more efficacious management options in the future. Increased awareness among medical professionals is essential for the early diagnosis and best care of acute myocarditis patients.

Emerging pharmacologic targets and treatments for myocarditis

Myocarditis is a heterogeneous group of disorders defined by inflammation of the heart muscle. The primary clinical manifestations of myocarditis are heart failure and sudden death in children and young adults. Numerous interventions have been investigated for the treatment of myocarditis, including broad spectrum alteration of the immune response and antiviral treatments; however, success has been limited. Since the myocarditis treatment trials in the 1990s there has been an improved understanding of disease progression and new facets of the immune response have been discovered. This new information provides fresh opportunities to develop therapeutics to treat myocarditis. This review analyzes previous pharmacologic approaches including immunosuppression, high dose intravenous immunoglobulin treatment, immunoadsorption and antiviral treatments, and looks forward toward recently identified immune factors that can be exploited as targets for new treatments. Such strategies include bolstering beneficial regulatory T cells or mitigating the detrimental Th17 T cells which can drive autoimmunity in the heart. The surging interest of the application of humanized monoclonal antibodies makes targeting deleterious arms of the immune response like Th17 cells a tangible goal in the near future. Promising constituents of herbal remedies have also been identified that may hold potential as new pharmacological treatments for myocarditis, however, significant work remains to elucidate the pharmacokinetics and side-effects of these compounds. Finally, advances in our understanding of the function of Matrix Metalloproteinases yield another target for altering disease progression given their role in the development of fibrosis during Dilated Cardiomyopathy. In bringing to light the various new targets and treatments available since the last myocarditis treatment trials, the aim of this review is to explore the new treatments that are possible in new myocarditis treatment trials.

Giant Cell Myocarditis: Not Always a Presentation of Cardiogenic Shock

Giant cell myocarditis is a rare and often fatal disease. The most obvious presentation often described in the literature is one of rapid hemodynamic deterioration due to cardiogenic shock necessitating urgent consideration of mechanical circulatory support and heart transplantation. We present the case of a 60-year-old man whose initial presentation was consistent with myopericarditis but who went on to develop a rapid decline in left ventricular systolic function without overt hemodynamic compromise or dramatic symptomatology. Giant cell myocarditis was confirmed via endomyocardial biopsy. Combined immunosuppression with corticosteroids and calcineurin inhibitor resulted in resolution of symptoms and sustained recovery of left ventricular function one year later. Our case highlights that giant cell myocarditis does not always present with cardiogenic shock and should be considered in the evaluation of new onset cardiomyopathy of uncertain etiology as a timely diagnosis has distinct clinical implications on management and prognosis.

Viral myocarditis--diagnosis, treatment options, and current controversies

Myocarditis--a frequent cause of dilated cardiomyopathy and sudden cardiac death--typically results from cardiotropic viral infection followed by active inflammatory destruction of the myocardium. Characterization of this disease has been hampered by its heterogeneous clinical presentations and diverse aetiologies. Advances in cardiac MRI and molecular detection of viruses by endomyocardial biopsy have improved our ability to diagnose and understand the pathophysiological mechanisms of this elusive disease. However, therapeutic options are currently limited for both the acute and chronic phases of myocarditis. Several randomized, controlled trials have demonstrated potential benefit with immunosuppressive and immunomodulatory therapies, but further investigations are warranted. In this Review, we explore the pathophysiology, natural history, and modes of diagnosis of myocarditis, as well as evidence-based treatment strategies. As novel imaging techniques and human in vitro models of the disease emerge, the landscape of therapies for myocarditis is poised to improve.

Fatal recurrence of fulminant giant cell myocarditis and recovery after initialisation of an alternative immunosuppressive regime

We report on a challenging case of a 34-year-old male patient with giant cell myocarditis (GCM) and fulminant relapse after discontinuing immunomodulatory therapy 2 years after the initial event. Specific combined immunosuppressive therapy with antithymocyte globulin (ATG), cyclosporine and high-dose glucocorticoids combined with guideline-based heart failure medication led to the recovery of GCM, improvement of systolic left ventricular function and clinical remission. This case report emphasises the importance of an immunosuppressive therapy for the prognosis and outcome and the risk of discontinuation. Most importantly, ATG seems to be one new possible potential treatment option for patients with acute GCM.

Myocarditis: diagnosis and treatment

OPINION STATEMENT

Myocarditis is a condition that can have a very wide clinical spectrum ranging from asymptomatic forms to fatal disease, but mostly presenting as new onset heart failure with reduced left ventricular ejection fraction, with or without viral syndrome. This condition is an important cause of sudden cardiac death in young patients. High risk features include second and third degree atrioventricular block or malignant arrhythmias. The diagnostic work-up may be challenging, but non-invasive imaging, primarily cardiac magnetic resonance, plays an increasingly important role, although endomyocardial biopsy is still considered a gold standard for diagnosis. Most importantly, myocarditis can transition to non-ischemic cardiomyopathy with eventually poor outcome. In this review, we will summarize the data on different diagnostic and treatment modalities of this disease.

Diagnosis, treatment, and outcome of giant-cell myocarditis in the era of combined immunosuppression

BACKGROUND

Giant-cell myocarditis often escapes diagnosis until autopsy or transplantation and has defied proper treatment trials for its rarity and deadly behavior. Current therapy rests on multiple-drug immunosuppression but its prognostic influence remains poorly known. We set out to analyze (1) our experience in diagnosing giant-cell myocarditis and (2) the outcome of patients on combined immunosuppression.

METHODS AND RESULTS

We reviewed the histories, diagnostic procedures, details of treatment, and outcome of 32 consecutive patients with histologically verified giant-cell myocarditis treated in our hospital since 1991. Twenty-six patients (81%) were diagnosed by endomyocardial or surgical biopsies and 6 at autopsy or post-transplantation. Twenty-eight (88%) patients underwent endomyocardial biopsy. The sensitivity of transvenous endomyocardial biopsy increased from 68% (19/28 patients) to 93% (26/28) after up to 2 repeat procedures. The 26 biopsy-diagnosed patients were treated with combined immunosuppression (2-4 drugs) including cyclosporine in 20 patients. The Kaplan-Meier estimates of transplant-free survival from symptom onset were 69% at 1 year, 58% at 2 years, and 52% at 5 years. Of the transplant-free survivors, 10/17 (59%) experienced sustained ventricular tachyarrhythmias during follow-up and 3 received intracardiac defibrillator shocks for ventricular tachycardia or fibrillation.

CONCLUSIONS

Repeat endomyocardial biopsies are frequently needed to diagnose giant-cell myocarditis. On contemporary immunosuppession, two thirds of patients reach a partial clinical remission characterized by freedom from severe heart failure and need of transplantation but continuing proneness to ventricular tachyarrhythmias.

Autoimmune giant cell myocarditis: clinical characteristics, experimental models and future treatments

INTRODUCTION

Although prognosis in acute myocarditis is generally moderate, giant cell myocarditis shows poor prognosis. Giant cell myocarditis is considered to be an autoimmune disease, however, its pathophysiology and specific treatment is yet to be elucidated.

AREAS COVERED

This article reviews the clinical characteristics of autoimmune myocarditis and its possible future treatments. An animal model of experimental autoimmune myocarditis (EAM) is characterized by severe myocardial damage and multinucleated giant cell infiltration, and this has been used as a disease model for human acute giant cell myocarditis. Using experimental models, we reported that NF-κB, cytokines, adhesion molecules and other factors play a critical role in the development of autoimmune myocarditis.

EXPERT OPINION

Giant cell myocarditis, an autoimmune form of myocarditis, has a high mortality rate unless mechanical support or cardiac transplantation is performed. Therefore, further therapeutic applications of novel methodologies are needed to expand the number of alternative choices for treating autoimmune myocarditis.

Hyperacute graft rejection during heart transplantation for giant cell myocarditis: a case report

We report the case of a patient with giant cell myocarditis who was bridged to transplantation with mechanical circulatory support and developed a fatal perioperative hyperacute rejection. The patient had received abundant transfusions that had raised her anti-HLA antibody titers. The cross-match test was positive. No pre-transplantation immunosuppressive therapy had been administered given concomitant infection. The severity and acuteness of the rejection in this case likely reflect the combined effect of preformed anti-HLA antibodies in the context of an active organ-specific immune process at the time of transplantation. This case raises the questions of the need for intensive immunosuppressive therapy before transplantation in giant cell myocarditis and of the management of patients with positive cross-match in the context of a giant cell myocarditis.

Fulminant giant cell myocarditis and cardiogenic shock: an unusual presentation of malignant thymoma

Malignant thymoma is rarely associated with giant cell myocarditis. We present a case study that illustrates this association and cardiogenic shock with underlying tamponade. The dramatic presentation of this scenario has not been previously described.

Anti-thymocyte globulin as an adjunct to treatment of fulminant lymphocytic myocarditis

There is much debate over the role of immunosuppression in the treatment of acute and fulminant myocarditis. The low incidence of the condition prevents large numbers of cases for study, and treatment protocols vary greatly between institutions. In this study we add our experience with anti-thymocyte globulin as an adjunct to standard medical therapy for 5 patients presenting with cardiogenic shock due to fulminant myocarditis. All cases were associated with rapid and dramatic improvement in hemodynamic and electrophysiologic abnormalities, returning patients to NYHA Class I and cardiac function to normal or near normal by discharge.

Isolated giant cell myocarditis in the atrium: an incidental finding?

Giant cell myocarditis (GCM) is an uncommon disorder that affects ventricular myocardium causing severe left ventricular dysfunction and ventricular arrhythmias. We report a case of GCM that only affected the atrium sparing the ventricle.

Muronomab-CD3 for pediatric acute myocarditis

The treatment of pediatric acute myocarditis that is hemodynamically significant often includes immune modulation with intravenous immunoglobulin (IVIG) and steroids, and supportive measures. In this population, published outcomes include recovery of ventricular function from 6 months to years, transplantation, or death. We studied the effect of the immunosuppressive agent muronomab-CD3 (OKT3) on recovery of heart failure in the treatment of pediatric myocarditis. A retrospective chart review was performed identifying 15 pediatric patients diagnosed with acute myocarditis and depressed left ventricular ejection fraction (LVEF) or arrhythmias to which OKT3 was added to the immunosuppressive regimen. All patients were treated with supportive care, intravenous immunoglobulin, and steroids. LVEF by echocardiogram was plotted for each patient versus time. Outcomes included recovery of left ventricular function (as defined by an LVEF > or = 45%), death, or listing for transplant. The diagnosis of acute myocarditis was made by a positive endomyocardial biopsy in 8 patients. Nine patients required extracorporeal membrane oxygenation (ECMO) or LV assist device. After treatment with OKT3, 9 patients made a significant recovery of LVEF within 17 days, and 1 recovered by 60 days. Six of the patients requiring mechanical assistance recovered within this time period. There were 4 deaths--3 due to ECMO complications and 1 due to underlying gastrointestinal illness. One patient diagnosed with chronic myocarditis on biopsy underwent transplantation. No significant side effects attributable to OKT3 occurred. By decreasing the autoimmune inflammatory response, OKT3 may hasten recovery of ventricular function and be a useful adjunct therapy for hemodynamically significant acute pediatric myocarditis.

Transplantation for myocarditis: a controversy revisited

Myocarditis is a major cause of end-stage heart failure and is responsible for up to 10% of cases of idiopathic dilated cardiomyopathy (IDC). Worldwide, approximately 45% of all heart transplants are performed for IDC and up to 8% for myocarditis. Early reports suggested that survival after transplantation for myocarditis was poor and patients had an increased risk of rejection. More recently, larger case series suggest that overall survival after transplantation for myocarditis is similar to survival after transplantation for other causes. However, certain disorders, including cardiac sarcoidosis and giant cell myocarditis (GCM), require heightened surveillance for post-transplantation disease recurrence. We present the case of a 42-year-old man with recurrence of GCM 8 years after transplantation and review the literature on the role of cardiac transplantation for patients with myocarditis.

Coronary artery disease obscuring giant cell myocarditis--a case report

A case in which the diagnosis of idiopathic giant cell myocarditis was obscured by the presence of severe coronary artery disease is described. A 47-year-old man presented with recurrent inferior myocardial infarction and complete heart block. Cardiac catheterization confirmed severe 2-vessel disease and left ventricular dysfunction. Incessant ventricular arrhythmia rapidly ensued, which did not respond to anti-arrhythmic therapy and overdrive pacing despite complete surgical revascularization. He eventually died. Autopsy revealed giant cell myocarditis superimposed on coronary artery disease. Acute myocarditis masquerading as myocardial infarction has been well known, but virtually all reported cases had normal coronary arteries. This case illustrated the fact that even in the presence of obvious coronary artery disease the remote possibility of myocarditis should not be entirely disregarded. Although giant cell myocarditis is a rare and frequently fatal disorder, recent studies suggest that combined immunosuppressive therapy may improve the prognosis.

[Giant cell myocarditis. A case report]

Giant cell myocarditis is a rare disease of unknown origin that is probably autoimmune in nature; the prognosis is poor and death often ensues unless a heart transplant is performed. Several cases responding to immunosuppressive therapy have been recently reported, however. We describe a patient who developed fulminant heart failure requiring heart transplantation. Examination of the explanted heart confirmed the diagnosis of giant cell myocarditis.

Giant cell myocarditis: clinical presentation, bridge to transplantation with mechanical circulatory support, and long-term outcome

BACKGROUND

The multicenter Giant Cell Myocarditis Registry recorded 64 cases from 36 centers before 1996. The median transplant-free survival of 30 patients without immunosuppression was 3 months. Of 34 patients who received heart transplantations, 9 experienced recurrence of giant cell myocarditis in their transplanted hearts and 1 patient died.

METHODS

We reviewed our experience in 340 heart transplantations since 1984. Unexpected giant cell myocarditis was found in the explanted hearts of 7 patients (6 men and 1 female, aged 18-65 years).

RESULTS

The duration from the onset of symptoms to assist-device implant or transplantation ranged from 11 days to 9 years, whereas the time interval from referral or deterioration ranged from 2 days to 4 months. Four patients required mechanical circulatory support before surgery (total artificial hearts in 2 and left ventricular assist devices in 2), and 3 patients required inotropic drugs. Six patients are alive with no sign of recurrent giant cell myocarditis at 12 to 113 months after surgery. One patient died suddenly 75 months after surgery, and autopsy showed severe graft vascular disease with no recurrence of giant cell myocarditis. Surveillance, right ventricular endomyocardial biopsy specimens showed recurrent asymptomatic giant cell myocarditis in 3 patients at 5 to 13 months after surgery, and found recurrence in 1 patient 30 months after surgery. This patient received augmented immunosuppression.

CONCLUSIONS

Giant cell myocarditis often is not diagnosed before transplantation. It can present as dilated cardiomyopathy with late deterioration, or it can present with rapid hemodynamic deterioration. In our experience, these patients can be bridged successfully to transplant with mechanical circulatory assist. Giant cell myocarditis may recur after transplantation but may respond to augmented immunosuppression.

Innovative drug treatments for viral and autoimmune myocarditis

Myocarditis is a common cause of cardiomyopathy and is thought to account for 25% of all cases in humans. Unfortunately, the disease is difficult to detect clinically before a myopathic process ensues. Management of myocarditis-induced heart failure includes the standard regimen of diuretics, digoxin, angiotensin-converting enzyme inhibitors, angiotensin-II receptor blockers, and beta-adrenergic blockers. The management of myocarditis itself is dependent on the etiology of the illness. Treatments that are currently under investigation include immunosuppressants, nonsteroidal antiinflammatory agents, immunoglobulins, immunomodulation, antiadrenergics, calcium-channel blockers, angiotensin-converting enzyme inhibitors, nitric oxide inhibitors (e.g., aminoguanidine), and antivirals. Despite advances in treatment, more work needs to be done in the early detection of myocarditis. Additionally, better means need to be established for distinguishing between viral and noninfectious autoimmune forms of the disease, so that appropriate treatment can be instituted.

The role of right ventricular endomyocardial biopsy for idiopathic giant cell myocarditis

BACKGROUND

Idiopathic giant cell myocarditis (GCM) is an uncommon cause of cardiac failure distinguished clinically from lymphocytic myocarditis by rapidly progressive heart failure, arrhythmias, and heart block. Unlike fulminant lymphocytic myocarditis, patients with fulminant cardiac failure caused by GCM may respond to certain immunosuppressive agents; however, right ventricular endomyocardial biopsy (EMB) is infrequently used to establish the diagnosis partly because the sensitivity of EMB for GCM is unknown. The purpose of this study was to estimate the sensitivity of right ventricular EMB for GCM in a referral population.

METHODS AND RESULTS

Twenty subjects (of 63 total) in the Multicenter Giant Cell Myocarditis Registry underwent both right ventricular EMB and heart pathology (HRTP) evaluation from apical wedge, explantation, or autopsy. The false-negative rate of right ventricular EMB was defined as the ratio of negative EMB to positive HRTP results. Ten of the 20 subjects were women. The mean age was 38 years (range, 16-53 years). Twelve (60%) subjects had a positive EMB and positive HRTP confirming GCM. Three (15%) had a negative EMB and positive HRTP for GCM. Five had a positive EMB and negative HRTP evaluation for GCM. The resulting sensitivity of EMB for GCM was 80% (12/15) with a positive predictive value of 71%. Assuming the 5 subjects with a positive EMB and negative HRTP are true positives, the sensitivity improves to 85% (17/20). Predictors of negative HRTP after positive EMB were time from symptom onset to HRTP (P.006) and time from EMB to HRTP (P.03).

CONCLUSIONS

The sensitivity of right ventricular EMB is high in patients with GCM who have early disease presentation and a fulminant clinical course. Although these results may not apply to individuals with less aggressive disease, EMB may be used selectively to distinguish fulminant heart failure caused by GCM from other causes in which the prognosis may differ.

Idiopathic Giant Cell Myocarditis

Idiopathic giant cell myocarditis (IGCM) is an uncommon disorder that is of general importance because it most commonly affects young individuals, is usually fatal without treatment, and may respond to aggressive medical and surgical therapy. IGCM is most often progressive over days to weeks and frequently requires the concurrent management of congestive heart failure, tachyarrhythmias, and heart block. After common causes of heart disease are excluded, the diagnosis must be confirmed by endomyocardial biopsy. Standard pharmacologic therapy for New York Heart Association functional class II to III congestive heart failure due to left ventricular systolic failure includes an angiotensin-converting enzyme inhibitor, a beta-blocker such as carvedilol, and diuretics as needed. We avoid digoxin and reserve inotropic agents for patients whose circulatory requirements cannot be supported with standard oral vasodilators and diuretics. Heart block may require a temporary or permanent pacemaker. Ventricular tachycardia is common and usually is managed chronically with an implantable cardiac defibrillator and antiarrhythmic drugs such as amiodarone. Despite optimal medical management, mechanical support may be required as a temporary bridge to recovery or transplantation. The intra-aortic balloon pump and ventricular assist device have been used successfully for patients with refractory pump failure due to acute IGCM. Heart transplantation is efficacious, with a 71% 5-year survival, despite a 20% to 25% rate of histologic recurrence in surveillance endomyocardial biopsies. The role of aggressive immunosuppression as part of the primary treatment of IGCM is under active investigation. Preliminary data suggest that primary therapy with a regimen that includes muromonab-CD3, cyclosporine, and steroids may significantly improve transplant-free survival.

Giant cell myocarditis as a manifestation of drug hypersensitivity

Adverse drug effects on the myocardium are often classified into toxic and hypersensitivity forms of myocarditis, each with distinct histologic findings. In contrast, giant cell myocarditis (GCM) is generally not associated with adverse drug reactions and has unique histopathologic features. We report four cases of adverse drug reactions in which the histologic findings were characteristic of GCM. The clinical recognition that GCM may be a manifestation of an adverse drug reaction is important, since the prognosis and treatment of this entity may be different from that of other forms of myocarditis.

Giant cell myocarditis: most fatal of autoimmune diseases

OBJECTIVE

To increase awareness of giant cell myocarditis (GCM), its pathogenesis, and treatment.

METHODS

Review of relevant publications from the English-language literature.

RESULTS

GCM is a rare, frequently fatal inflammatory disorder of cardiac muscle of unknown origin, characterized by widespread degeneration and necrosis of myocardial fibers.Congestive heart failure and ventricular tachycardia are common clinical manifestations. GCM occurs primarily in previously healthy adults, although it is frequently associated with various systemic diseases, primarily of autoimmune causes. The inflammatory infiltrate is characterized by the presence of multinucleated giant cells and is distinct from cardiac sarcoidosis. Animal models of GCM are similar to models of other autoimmune disorders such as rheumatoid arthritis. The prognosis, which is poor despite partial responsiveness to immunosuppressive medications, is improved with cardiac transplantation.

CONCLUSIONS

The clinical and immunopathogenetic similarities with classical rheumatologic diseases, the differential diagnosis with sarcoidosis and other inflammatory conditions, and the use of standard immunosuppressive medications make GCM a disease process that should be added to the rheumatologist's expertise.