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

Acute myocarditis: an overview of pathogenesis, diagnosis and management

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

Understanding long COVID myocarditis: A comprehensive review

Infectious diseases are a cause of major concern in this twenty-first century. There have been reports of various outbreaks like severe acute respiratory syndrome (SARS) in 2003, swine flu in 2009, Zika virus disease in 2015, and Middle East Respiratory Syndrome (MERS) in 2012, since the start of this millennium. In addition to these outbreaks, the latest infectious disease to result in an outbreak is the SARS-CoV-2 infection. A viral infection recognized as a respiratory illness at the time of emergence, SARS-CoV-2 has wreaked havoc worldwide because of its long-lasting implications like heart failure, sepsis, organ failure, etc., and its significant impact on the global economy. Besides the acute illness, it also leads to symptoms months later which is called long COVID or post-COVID-19 condition. Due to its ever-increasing prevalence, it has been a significant challenge to treat the affected individuals and manage the complications as well. Myocarditis, a long-term complication of coronavirus disease 2019 (COVID-19) is an inflammatory condition involving the myocardium of the heart, which could even be fatal in the long term in cases of progression to ventricular dysfunction and heart failure. Thus, it is imperative to diagnose early and treat this condition in the affected individuals. At present, there are numerous studies which are in progress, investigating patients with COVID-19-related myocarditis and the treatment strategies. This review focuses primarily on myocarditis, a life-threatening complication of COVID-19 illness, and endeavors to elucidate the pathogenesis, biomarkers, and management of long COVID myocarditis along with pipeline drugs in detail.

Giant cell myocarditis with prolonged cardiac standstill after drug-induced hypersensitivity syndrome: a case report

Giant cell myocarditis (GCM) is a rare but fatal disease that can lead to cardiac failure. Survival with a cardiac standstill requires mechanical circulatory support or a biventricular assist device (BiVAD) and prolonged survival is extremely rare. Drug-induced hypersensitivity syndrome (DIHS) is a severe cutaneous adverse reaction. Some cases of DIHS are reportedly associated with the onset of GCM. We present a case of a 28-year-old woman who developed GCM during steroid tapering after DIHS. She went into continuous cardiac standstill but survived for 74 days under BiVAD support. Our case is noteworthy because the histopathologic specimens obtained on three occasions contributed to the diagnosis of this particular condition over time. We also reviewed previous literature on concomitant cases of GCM and DIHS. We found that two are potentially associated and most cases of GCM occur within 3 months of DIHS during steroid tapering.

Two case reports of fulminant giant cell myocarditis treated with rabbit anti-thymocyte globulin

Background

Giant cell myocarditis (GCM) is an inflammatory form of acute heart failure with high rates of cardiac transplantation or death. Standard acute treatment includes multi-drug immunosuppressive regimens. There is a small but growing number of case reports utilizing rabbit anti-thymocyte globulin in severe cases.

Case summary

Two cases are presented with similar presentations and clinical courses. Both are middle-aged patients with no significant past medical history, who presented with new acute decompensated heart failure that quickly progressed to cardiogenic shock requiring inotropic and mechanical circulatory support. Both underwent endomyocardial biopsies that diagnosed GCM. Both were treated with a multi-agent immunosuppressive regimen, notably including rabbit anti-thymocyte globulin, with subsequent resolution of shock and recovery of left ventricular ejection fraction. Both remain transplant-free and without ventricular arrhythmias at 7 months and 26 months, respectively.

Discussion

In aggregate, these cases are typical of GCM. They add to growing observational data that upfront rabbit anti-thymocyte globulin may reduce morbidity and mortality in GCM, including potentially preventing the need for complex interventions like orthotopic heart transplantation.

Cardiovascular magnetic resonance (CMR) and positron emission tomography (PET) imaging in the diagnosis and follow-up of patients with acute myocarditis and chronic inflammatory cardiomyopathy : A review paper with practical recommendations on behalf of the European Society of Cardiovascular Radiology (ESCR)

Advanced cardiac imaging techniques such as cardiovascular magnetic resonance (CMR) and positron emission tomography (PET) are widely used in clinical practice in patients with acute myocarditis and chronic inflammatory cardiomyopathies (I-CMP). We aimed to provide a review article with practical recommendations from the European Society of Cardiovascular Radiology (ESCR), in order to guide physicians in the use and interpretation of CMR and PET in clinical practice both for acute myocarditis and follow-up in chronic forms of I-CMP.

Immunomodulatory Therapy for Giant Cell Myocarditis: A Narrative Review

Giant cell myocarditis (GCM) is a rare, often rapidly progressive, and potentially fatal disease because of myocardium inflammation due to the infiltration of giant cells triggered by infectious as well as non-infectious etiologies. Several studies have reported that GCM can occur in patients of all ages but is more commonly found in adults. It is relatively more common among African American and Hispanic patients than in the White population. Early diagnosis and treatment are critical. Electrocardiogram (EKG), complete blood count, erythrocyte sedimentation rate, C-reactive protein, and cardiac biomarkers such as troponin and brain natriuretic peptide (BNP), echocardiogram, cardiac magnetic resonance imaging (MRI), myocardial biopsy, and myocardial gene profiling are useful diagnostic tools. Current research has identified several potential biomarkers for GCM, including myocarditis-associated immune cells, cytokines, and other chemicals. The standard of care for GCM includes aggressive immunosuppressive therapy with corticosteroids and immunomodulatory agents like rituximab, cyclosporine, and infliximab, which have shown promising results in GCM by balancing the immune system and preventing the attack on healthy tissues, resulting in the reduction of inflammation, promotion of healing, and decreasing the necessity for cardiac transplantation. Without immunosuppression, the chance of mortality or cardiac surgery was 100%. Multiple studies have revealed that a treatment combination of corticosteroids and immunomodulatory agents is superior to corticosteroids alone. Combination therapy significantly increased transplant-free survival (TFS) and decreased the likelihood of heart transplantation, hence improving overall survival. It is important to balance the benefits of immunosuppression with its potentially adverse effects. In conclusion, immunomodulatory therapy adds significant long-term survival benefits to GCM.

Research focus and theme trend on fulminant myocarditis: A bibliometric analysis

Aims

This study intends to explore the research focus and trends of fulminant myocarditis (FM) to have a better understanding of the topic.

Materials and methods

The data were downloaded from the Web of Science (WoS) database using the topic (TS) advanced search strategy. Many instruments were used to extract, analyze, and visualize the data, such as Microsoft Excel, HistCite Pro, GunnMap, BibExcel, and VOSviewer.

Results

From 1985 to 2022, 726 documents were indexed in the WoS. The United States and Columbia University were the most productive country and institutions. Keywords co-occurrence was carried out and four research themes were identified. In addition, the top three prolific authors, the first three highly cited authors, and the core authors of the author co-citation network were identified. The topics that they kept an eye on were analyzed, and the research areas of key authors were similar to the results of keyword co-occurrence. The hot topics of FM were related to the mechanical circulatory support, etiology, diagnosis, and the disease or therapy associated with FM.

Conclusion

This study carried out a systematic analysis of the documents related to FM from 1985 to 2022, which can provide a guideline for researchers to understand the theme trend to promote future research to be carried out.

Tuberculosis of the Heart: A Diagnostic Challenge

Tuberculosis of the heart is relatively rare and presents a significant diagnostic difficulty for physicians. It is the leading cause of death from infectious illness. It is one of the top 10 leading causes of death worldwide, with a disproportionate impact in low- and middle-income nations. The radiologist plays a pivotal role as CMR is a non-invasive radiological method that can aid in identifying potential overlap and differential diagnosis between tuberculosis, mass lesions, pericarditis, and myocarditis. Regardless of similarities or overlap in observations, the combination of clinical and certain particular radiological features, which are also detected by comparison to earlier and follow-up CMR scans, may aid in the differential diagnosis. CMR offers a significant advantage over echocardiography for detecting, characterizing, and assessing cardiovascular abnormalities. In conjunction with clinical presentation, knowledge of LGE, feature tracking, and parametric imaging in CMR may help in the early detection of tuberculous myopericarditis and serve as a surrogate for endomyocardial biopsy resulting in a quicker diagnosis and therapy. This article aims to explain the current state of cardiac tuberculosis, the diagnostic utility of CMR in tuberculosis (TB) patients, and offer an overview of the various imaging and laboratory procedures used to detect cardiac tuberculosis.

The role of cardiovascular magnetic resonance in the evaluation of acute myocarditis and inflammatory cardiomyopathies in clinical practice - a comprehensive review

Inflammatory cardiomyopathy (I-CMP) is defined as myocarditis in association with cardiac dysfunction and/or ventricular remodelling. It is characterized by inflammatory cell infiltration into the myocardium and has heterogeneous infectious and non-infectious aetiologies. A complex interplay of genetic, autoimmune, and environmental factors contributes to the substantial risk of deteriorating cardiac function, acute heart failure, and arrhythmia as well as chronic dilated cardiomyopathy and its sequelae. Multi-parametric cardiovascular magnetic resonance (CMR) imaging is sensitive to many tissue changes that occur during myocardial inflammation, regardless of its aetiology. In this review, we summarize the various aetiologies of I-CMP and illustrate how CMR contributes to non-invasive diagnosis.

Giant Cell Myocarditis in Children: Elusive Giant Cells Might Not Be the Only Clue

Giant cell myocarditis (GCM) is a form of fulminant myocarditis that is rapidly progressive and frequently lethal even in children. Over the course of 20 years, a definitive histopathologic diagnosis of GCM has been made at our institution in only two pediatric patients, and in neither instance was the diagnosis of GCM rendered on initial cardiac biopsy. We present the two patients and highlight the similarities in their clinical presentation and their challenging and inconclusive- albeit histologically similar- initial cardiac biopsy findings.

Fulminant myocarditis following coronavirus disease 2019 vaccination: a case report

Background

The BNT162b2 vaccine received emergency use authorization from the U.S. Food and Drug Administration for the prevention of severe coronavirus disease 2019 (COVID-19) infection. We report a case of biopsy and magnetic resonance imaging (MRI)-proven severe myocarditis that developed in a previously healthy individual within days of receiving the first dose of the BNT162b2 COVID-19 vaccine.

Case Summary

An 80-year-old female with no significant cardiac history presented with cardiogenic shock and biopsy-proven fulminant myocarditis within 12 days of receiving the BNT162b2 COVID-19 vaccine. She required temporary mechanical circulatory support, inotropic agents, and high-dose steroids for stabilization and management. Ultimately, her cardiac function recovered, and she was discharged in stable condition after 2 weeks of hospitalization. A repeat cardiac MRI 3 months after her initial presentation demonstrated stable biventricular function and continued improvement in myocardial inflammation.

Discussion

Fulminant myocarditis is a rare complication of vaccination. Clinicians should stay vigilant to recognize this rare, but potentially deadly complication. Due to the high morbidity and mortality associated with COVID-19 infection, the clinical benefits of the BNT162b2 vaccine greatly outweighs the risks of complications.

The role of endomyocardial biopsy in suspected myocarditis in the contemporary era: a 10-year National Transplant Centre experience

BACKGROUND

Diagnostic endomyocardial biopsy (EMB) in patients with suspected myocarditis helps to direct therapy and guide prognosis. This study aimed to investigate the correlation between the 2007 clinical guideline indications for EMB and the presence of a diagnostic biopsy result and associated outcomes in patients with suspected myocarditis in a national quaternary referral center in a contemporary cohort.

METHODS

All cases of suspected myocarditis referred to the National Cardiac Transplant Centre who underwent EMB between 2009 and 2019 were identified retrospectively through pathology records. Outcomes including subsequent need for inotrope and/or mechanical circulatory support (MCS), heart transplantation and in-hospital mortality were recorded.

RESULTS

In total, 25 (68% male, mean age of 45 ± 15 years) EMBs were performed for this indication across this time period, 64% (n = 16) of which demonstrated diagnostic results, the majority (75%, n = 12) identifying acute lymphocytic myocarditis, 13% (n = 2) giant cell, one patient (6.3%) eosinophilic and one (6.3%) an immune checkpoint inhibitor myocarditis. The majority of those with histologically confirmed myocarditis had a Class I or IIa guideline indication for EMB (n = 12, 75%). The remaining 4 patients (25%), either met Class IIb criteria (n = 2) or would not have been accounted for in this guideline. The majority of patients requiring inotropes and/or MCS (n = 9/11), and/or heart transplant (n = 3/4), or who later died (n = 4/5) were in the diagnostic biopsy group.

CONCLUSIONS

In this 10-year National referral sample, 75% of patients with histologically confirmed myocarditis had a Class I or IIa indication for EMB, reinforcing the usefulness of traditional guidelines in this contemporary era. However, 25% of patients with a subsequent confirmed histological diagnosis had either none or a less well-established indication for EMB, highlighting the need for clinical suspicion outside of accepted clinical scenarios.

Heart Failure Association of the ESC, Heart Failure Society of America and Japanese Heart Failure Society Position statement on endomyocardial biopsy

Endomyocardial biopsy (EMB) is an invasive procedure, globally most often used for the monitoring of heart transplant (HTx) rejection. In addition, EMB can have an important complementary role to the clinical assessment in establishing the diagnosis of diverse cardiac disorders, including myocarditis, cardiomyopathies, drug-related cardiotoxicity, amyloidosis, other infiltrative and storage disorders, and cardiac tumours. Improvements in EMB equipment and the development of new techniques for the analysis of EMB samples have significantly improved diagnostic precision of EMB. The present document is the result of the Trilateral Cooperation Project between the Heart Failure Association of the European Society of Cardiology, the Heart Failure Society of America, and the Japanese Heart Failure Society. It represents an expert consensus aiming to provide a comprehensive, up-to-date perspective on EMB, with a focus on the following main issues: (i) an overview of the practical approach to EMB, (ii) an update on indications for EMB, (iii) a revised plan for HTx rejection surveillance, (iv) the impact of multimodality imaging on EMB, and (v) the current clinical practice in the worldwide use of EMB.

Heart Failure Association, Heart Failure Society of America, and Japanese Heart Failure Society Position Statement on Endomyocardial Biopsy

Endomyocardial biopsy (EMB) is an invasive procedure, globally most often used for the monitoring of heart transplant rejection. In addition, EMB can have an important complementary role to the clinical assessment in establishing the diagnosis of diverse cardiac disorders, including myocarditis, cardiomyopathies, drug-related cardiotoxicity, amyloidosis, other infiltrative and storage disorders, and cardiac tumors. Improvements in EMB equipment and the development of new techniques for the analysis of EMB samples has significantly improved the diagnostic precision of EMB. The present document is the result of the Trilateral Cooperation Project between the Heart Failure Association of the European Society of Cardiology, Heart Failure Society of America, and the Japanese Heart Failure Society. It represents an expert consensus aiming to provide a comprehensive, up-to-date perspective on EMB, with a focus on the following main issues: (1) an overview of the practical approach to EMB, (2) an update on indications for EMB, (3) a revised plan for heart transplant rejection surveillance, (4) the impact of multimodality imaging on EMB, and (5) the current clinical practice in the worldwide use of EMB.

Late gadolinium enhancement characteristics in giant cell myocarditis

AIMS

This study aims to demonstrate the characteristics of late gadolinium enhancement (LGE) assessed by cardiovascular magnetic resonance (CMR) imaging in patients with giant cell myocarditis (GCM).

METHODS AND RESULTS

Six patients histologically diagnosed with GCM were retrospectively recruited in this study. All of them underwent CMR during hospitalization. The distribution and extent of LGE were assessed on both ventricles, and the AHA-17 segment model was used for left ventricular (LV) analysis. Nine case reports with CMR in GCM were reviewed and summarized to investigate the features of LGE further. LGE was detected on both ventricular walls in all subjects. For a detailed analysis of LGE in the LV, the extent ranged from 21.6% to 56%. Among 70 segments (68.6%) involved by LGE, the subendocardial LGE was the most common pattern (46/102, including 24 segments located in the right-sided septum), followed by the subepicardial pattern (23/102). The right-sided septum, the subepicardial anterior wall, and the subendocardial right ventricular (RV) wall were observed in all subjects. To summarize the results of the present study with these case reports, the three most common patterns of LGE are the right-sided septum (73%), the subepicardial anterior wall (60%), and the subendocardial RV wall (53%).

CONCLUSIONS

Extensive LGE seems to be common in GCM, affecting both LV and RV walls. Apart from subepicardial LGE, subendocardial LGE, which was used to be implicated in ischaemic disease, was frequently presented in GCM. The right-sided subendocardial septum, the subepicardial anterior wall, and the subendocardial RV wall might be the vulnerable areas of LGE in GCM.

Management of Patients With Giant Cell Myocarditis: JACC Review Topic of the Week

Giant cell myocarditis is a rare, often rapidly progressive and potentially fatal, disease due to T-cell lymphocyte-mediated inflammation of the myocardium that typically affects young and middle-aged adults. Frequently, the disease course is marked by acute heart failure, cardiogenic shock, intractable ventricular arrhythmias, and/or heart block. Diagnosis is often difficult due to its varied clinical presentation and overlap with other cardiovascular conditions. Although cardiac biomarkers and multimodality imaging are often used as initial diagnostic tests, endomyocardial biopsy is required for definitive diagnosis. Combination immunosuppressive therapy, along with guideline-directed medical therapy, has led to a paradigm shift in the management of giant cell myocarditis resulting in an improvement in overall and transplant-free survival. Early diagnosis and prompt management can decrease the risk of transplantation or death, which remain common in patients who present with cardiogenic shock.

Heart Transplantation for Giant Cell Myocarditis: A Case Series

BACKGROUND

Giant cell myocarditis (GCM) has a poor prognosis without heart transplant, but post-transplant survival is unknown.

PURPOSE

To describe the post-transplant survival of patients with GCM at a large transplant center.

METHODS

Seven patients underwent heart transplant for histologically confirmed GCM of the explanted heart. The median age was 59 years, and 43% (3 of 7) were female. All patients had cardiogenic shock, multiorgan failure, elevated troponin, and recurrent ventricular tachycardia, and some required mechanical circulatory support. All patients received rabbit antithymocyte globulin (rATG) in the perioperative period at a dose of 1.5 mg/kg daily for 1 to 5 days and 4 received intravenous immunoglobulin 1 g/kg daily for 2 days after rATG. All patients had early initiation of tacrolimus by first to third postoperative day depending on renal function, early mycophenolate, and high dose steroid. All were maintained using tacrolimus, mycophenolate, and prednisone.

RESULTS

One patient had asymptomatic recurrence of GCM at 3 months, managed by up-titration of tacrolimus, and had asymptomatic 2R cellular rejection at 4 months, managed with steroid bolus. No patient had high-grade rejection. One patient died at 267 days, possibly of GCM. Six of 7 (86%) remain alive at a median of 842 days (2.3 years) post transplant.

CONCLUSIONS

Patients with GCM have excellent post-transplant survival with use of rATG and triple drug immunosuppressive therapy; however, some patients remain at risk for GCM recurrence after transplant, which may respond to augmented immunosuppression.

Outcomes of Mechanical Circulatory Support for Giant Cell Myocarditis: A Systematic Review

Treatment of giant cell myocarditis (GCM) can require bridging to orthotopic heart transplantation (OHT) or recovery with mechanical circulatory support (MCS). Since the roles of MCS and immunotherapy are not well-defined in GCM, we sought to analyze outcomes of patients with GCM who required MCS. A systematic search was performed in June 2019 to identify all studies of biopsy-proven GCM requiring MCS after 2009. We identified 27 studies with 43 patients. Patient-level data were extracted for analysis. Median patient age was 45 (interquartile range (IQR): 32-57) years. 42.1% (16/38) were female. 34.9% (15/43) presented in acute heart failure. 20.9% (9/43) presented in cardiogenic shock. Biventricular (BiVAD) MCS was required in 76.7% (33/43) of cases. Of the 62.8% (27/43) of patients who received immunotherapy, 81.5% (22/27) used steroids combined with at least one other immunosuppressant. Cyclosporine was the most common non-steroidal agent, used in 40.7% (11/27) of regimens. Immunosuppression was initiated before MCS in 59.3% (16/27) of cases, after MCS in 29.6% (8/27), and not specified in 11.1% (3/27). Immunosuppression started prior to MCS was associated with significantly better survival than MCS alone (p = 0.006); 60.5% (26/43) of patients received bridge-to-transplant MCS; 39.5% (17/43) received bridge-to-recovery MCS; 58.5% (24/41) underwent OHT a median of 104 (58-255) days from diagnosis. GCM recurrence after OHT was reported in 8.3% (2/24) of transplanted cases. BiVAD predominates in mechanically supported patients with GCM. Survival and bridge to recovery appear better in patients on immunosuppression, especially if initiated before MCS.

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.

Sudden cardiac death due to ventricular fibrillation in a case of giant cell myocarditis

A 70-year-old woman was admitted to our hospital complaining of shortness of breath. She was diagnosed with acute decompensated heart failure due to left ventricular dysfunction. Her symptoms began to improve with standard therapy for heart failure with diuretics, noninvasive pressure ventilation, and inotropes, but paroxysmal atrial fibrillation and premature ventricular contractions (PVCs) occurred. After treatment with amiodarone, the number of PVCs decreased, and the left ventricular wall motion gradually improved. However, on day 28, ventricular fibrillation and cardiopulmonary arrest occurred suddenly, and she could not be resuscitated. She was diagnosed with giant cell myocarditis via an autopsy. The autopsy revealed diffuse inflammatory cells that comprised giant cells and eosinophils as well as cellular degeneration and necrosis. <Learning objective: We herein report a case of sudden cardiac death due to giant cell myocarditis diagnosed at an autopsy.>.

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.

Fulminant giant-cell myocarditis on mechanical circulatory support: Management and outcomes of a French multicentre cohort

AIMS

Giant-cell myocarditis (GCM) is a rare and often fatal form of myocarditis. Only a few reports have focused on fulminant forms. We describe the clinical characteristics, management and outcomes of GCM patients rescued by mechanical circulatory support (MCS).

METHODS AND RESULTS

The clinical features, diagnoses, treatments and outcomes of MCS-treated patients in refractory cardiogenic shock secondary to fulminant GCM admitted to eight French intensive care units (2002-2016) were analysed. We also conducted a systematic review of this topic. Thirteen patients (median age 44 [range 21-76]years, Simplified Acute Physiology Score II 55 [40-79]) in severe cardiogenic shock (median [range] left ventricular ejection fraction 15% [15-35%] and blood lactate 4 mmol/L) were placed on MCS 4 [0-28]days after hospital admission. Severe arrhythmic disturbances were frequent (77%), with six (46%) patients experiencing an electrical storm prior to MCS. Venoarterial extracorporeal membrane oxygenation was the first MCS option for 11 (85%) patients. GCM was diagnosed in five (38%) patients before transplant or death and treated with immunosuppressants; infections were the main complication (80%). Four patients died on MCS and no patient presented long-term survival free from heart transplant (nine patients, 69%). All transplanted patients were alive 1year later and no GCM recurrence was reported after median follow-up of 42 [12-145]months.

CONCLUSION

Outcomes of fulminant GCMs may differ from those of milder forms. In this context, heart transplant might likely be the only long-term survival option.

Giant cell myocarditis causing refractory ventricular tachycardia in a pediatric patient

Giant cell myocarditis should be considered in all pediatric patients with refractory ventricular arrhythmia. Endomyocardial biopsy should be obtained to confirm the diagnosis of giant cell myocarditis.

Giant Cell Myocarditis: A Brief Review

Giant cell myocarditis (GCM) is a rapidly progressive and frequently fatal disease that mainly affects young to middle-aged previously healthy individuals. Early diagnosis is critical, as recent studies have shown that rapidly instituted cyclosporine-based immunosuppression can reduce inflammation and improve transplant-free survival. Before the 1980s, GCM was mainly a diagnosis made at autopsy. Owing to advancements in diagnostic and therapeutic options, it is now increasingly diagnosed on the basis of endomyocardial biopsies, explanted hearts, or apical wedge sections removed at the time of ventricular assist device placement. Histologic examination remains the gold standard for diagnosis; however, there are many possible etiologies for cardiac giant cells. Having a working knowledge of the clinicopathologic features that distinguish GCM from other giant cell-containing lesions is essential, since such lesions can have widely divergent management and outcome.

The Quest for New Approaches in Myocarditis and Inflammatory Cardiomyopathy

Myocarditis is a diverse group of heart-specific immune processes classified by clinical and histopathological manifestations. Up to 40% of dilated cardiomyopathy is associated with inflammation or viral infection. Recent experimental studies revealed complex regulatory roles for several microribonucleic acids and T-cell and macrophage subtypes. Although the prevalence of myocarditis remained stable between 1990 and 2013 at about 22 per 100,000 people, overall mortality from cardiomyopathy and myocarditis has decreased since 2005. The diagnostic and prognostic value of cardiac magnetic resonance has increased with new, higher-sensitivity sequences. Positron emission tomography has emerged as a useful tool for diagnosis of cardiac sarcoidosis. The sensitivity of endomyocardial biopsy may be increased, especially in suspected sarcoidosis, by the use of electrogram guidance to target regions of abnormal signal. Investigational treatments on the basis of mechanistic advances are entering clinical trials. Revised management recommendations regarding athletic participation after acute myocarditis have heightened the importance of early diagnosis.

Giant cell myocarditis: a rare cardiovascular manifestation in a patient with systemic lupus erythematosus

Giant cell myocarditis (GCM) is a rare form of myocarditis with a median survival of less than one year. It has been reported to occur in patients with various underlying autoimmune diseases; however, no cases of GCM have been described in patients with clear evidence of underlying systemic lupus erythematosus (SLE). The presentation of GCM may mimic that of lupus myocarditis, including an initial response to immunosuppression. Despite initial clinical similarities, lupus myocarditis and GCM are histologically distinct entities with dramatic differences in prognosis. We report herein a patient with a longstanding history of SLE, who presented acutely with myocarditis, responded well to initial immunosuppression and then subsequently died of progressive heart failure that was found to be due to GCM. Endomyocardial biopsy can help define diagnosis and prognosis of lupus patients presenting with myocarditis, and early referral for cardiac transplantation should be considered in patients diagnosed with GCM.

Small steps for idiopathic giant cell myocarditis

Idiopathic giant cell myocarditis (IGCM) is a rare disease causing progressive myocarditis characterized by myocardial necrosis and giant cells. Patients often present with rapidly progressive heart failure, ventricular arrhythmias, and heart block. Without treatment, the disease often results in progressive pump failure requiring urgent cardiac transplantation or the need for mechanical circulatory support. The underlying pathophysiologic mechanisms are not yet defined but appear to involve genetics, autoimmune disorders, and possibly environmental factors such as viruses. Combined immunosuppressive regimens appear to prolong survival from death or cardiac transplant. Nevertheless, cardiac transplant is an effective treatment. The disease can recur in the transplanted heart resulting in death or the need for retransplant.

Spontaneous Remission in a Case of Giant Cell Myocarditis with Preserved Left Ventricular Ejection Fraction

Patient: Female, 28

Final Diagnosis: Giant cell myocarditis

Symptoms: Progressive shortness of breath and palpitation

Medication: None

Clinical Procedure: Endomyocardial biopsy • MRI • PET

Specialty: Cardiology

Usefulness of Rabbit Anti-thymocyte Globulin in Patients With Giant Cell Myocarditis

Giant cell myocarditis (GCM) is an aggressive inflammatory myocardial disease. Immunosuppression is an effective treatment for some cases. However, the duration of action of agents such as muromonab CD3 is short and others such as the calcineurin inhibitors may lead to renal failure. Here we describe the outcome of a novel approach to treatment using rabbit anti-thymocyte globulin (RATG). A retrospective analysis of 6 patients treated with RATG for GCM was performed. Diagnosis was confirmed by endomyocardial biopsy, and RATG was administered with a high dose of corticosteroids. None of the patients had cytokine release syndrome or leukopenia, and 5 had thrombocytopenia (2 of them severe). Only 1 had a serious bleeding event that occurred after implantation of mechanical circulatory support. None developed impaired renal function after the treatment. Five were successfully discharged home with an increase in global left ventricular ejection fraction of 29%. Four are currently alive without recurrent disease, 1 of them after heart transplantation, with a mean follow-up of 970 days (423 to 1,875 days), left ventricular ejection fraction of 53%, and all in current New York Heart Association Classification class ≤II. Only 1 case had GCM recurrence. There were 2 deaths: one because of intracranial bleeding after mechanical circulatory support implantation and the other caused by primary graft dysfunction. In conclusion, patients with GCM can be successfully immunosuppressed with RATG and corticosteroids, thereby avoiding renal impairment. Early thrombocytopenia is the main adverse event. Larger cohorts of patients are necessary to compare the different immunosuppressant strategies available for GCM in a randomized fashion.

Electrogram guidance: a method to increase the precision and diagnostic yield of endomyocardial biopsy for suspected cardiac sarcoidosis and myocarditis

OBJECTIVES

The aim of this study was to describe the method used to perform electrogram-guided EMB and correlate electrogram characteristics with pathological and clinical outcomes.

BACKGROUND

Endomyocardial biopsy (EMB) is valuable in determining the underlying etiology of a cardiomyopathy. The sensitivity, however, for focal disorders, such as lymphocytic myocarditis and cardiac sarcoidosis (CS), is low. The sensitivity of routine fluoroscopically guided EMB is low. Abnormal intracardiac electrograms are seen at sites of myocardial disease. However, the exact value of electrogram-guided EMB is unknown.

METHODS

We report 11 patients who underwent electrogram-guided EMB for evaluation of myocarditis and CS.

RESULTS

Of 40 total biopsy specimens taken from 11 patients, 19 had electrogram voltage <5 mV, all of which resulted in histopathologic abnormality (100% specificity and positive predictive value). A voltage amplitude cutoff value of 5 mV had substantially higher sensitivity (70% vs. 26%) and negative predictive value (62%) than 1.5 mV. Abnormal electrogram appearance at biopsy site had good sensitivity (67%) and specificity (92%) in predicting abnormal myocardium. Normal signals with voltage >5 mV signified normal myocardium with no significant diagnostic yield. Biopsy results guided therapy in all patients, including 5 with active myocarditis or CS, all of whom subsequently received immunosuppressive therapy. There were no procedural complications.

CONCLUSIONS

In patients with suspected myocarditis or CS, electrogram-guided EMB targeting sites with abnormal or low-amplitude electrograms may increase the diagnostic yield for detecting abnormal pathological findings.

The Changing Role for Endomyocardial Biopsy in the Diagnosis of Giant-Cell Myocarditis

Endomyocardial biopsy (EMB) is central to the diagnosis of giant-cell myocarditis (GCM) and planning further management. There is, however, no guideline-directed recommendation on re-biopsy or left ventricular EMB in a suspected case of acute, fulminant myocarditis following an indeterminate first biopsy. This manuscript illustrates, with a case, the changing role for EMB in the current era in the diagnosis of GCM.

Chest pain and palpitations: taking a closer look

This case highlights the importance of considering a wide differential diagnosis in a young patient with chest pain and an abnormal ECG. Rarer causes of myocarditis such as GCM should be sought in patients who develop ventricular arrhythmias or high-grade heart block because the treatment is different and dramatically influences outcome. Our patient is the first reported case of GCM and a concurrent diagnosis of tuberculosis. It is most likely that the histological appearance of GCM was due to the presence of mycobacterial infection within the myocardium, and we believe that effective antituberculous therapy has led to resolution of the GCM without the need for continued long-term immunosuppression.

Giant cell myocarditis in a patient with a spondyloarthropathy after a drug hypersensitivity reaction

A young woman thought to have seronegative rheumatoid arthritis developed Stevens-Johnson syndrome after treatment with sulfasalazine; this resolved with prednisone. Later she was found to be HLA-B27-positive in keeping with a spondyloarthropathy. Soon afterward, she developed clinical myopericarditis and cardiogenic shock that responded initially to methylprednisolone and intravenous immunoglobulin, but recurred. An endomyocardial biopsy demonstrated active myocarditis with a mixed cell composition including rare giant cells, but not enough to classify it as giant cell myocarditis. Heart failure symptoms returned and she eventually required a heart transplant; the explanted heart showed giant cell myocarditis.

An unusual case of giant cell myocarditis missed in a Heartmate-2 left ventricle apical-wedge section: a case report and review of the literature

Herein we present a case of fulminant myocarditis in a woman previously treated for B-cell lymphoma. While the clinical context was suggestive of adriamycin-induced cardiomyopathy, the initial pathology of the Heartmate-2 apical core showed lymphocytic myocarditis. After 8 months of stability, the patient presented with progressive heart failure and recurrent ventricular arrhythmias. An endomyocardial biopsy revealed findings typical of giant cell myocarditis (GCM); poor response to immunosuppressive therapy and marked hemodynamic instability led to urgent transplantation. To our knowledge, this is the first reported case of GCM following an acute lymphocytic myocarditis and the second GCM case associated with B-cell lymphoma.

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.