Giant cell versus lymphocytic myocarditis. A comparison of their clinical features and long-term outcomes

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.

Acute lymphocytic myocarditis presenting as complete heart block in an adult: a case report

BACKGROUND

Complete heart block (CHB) as a first presentation of acute viral myocarditis is a rare occurrence associated with increased morbidity and mortality. In such cases, an endomyocardial biopsy is recommended to make a clear histological diagnosis aiding to differentiate from other possible conditions such as sarcoiditic myocarditis, giant cell myocarditis, and eosinophilic myocarditis. Insertion of a permanent pacemaker may be considered on a case-to-case basis.

CASE PRESENTATION

A previously healthy 21-year-old female presented to the emergency department after having suffered two episodes of syncope on a background of a few days' history of myalgias, chills, and rigors. Electrocardiogram showed high-grade Mobitz II block with intermittent periods of CHB. A bedside echocardiogram upon admission demonstrated normal biventricular systolic function. Given the patient's unstable haemodynamic status and lack of obvious reversible causes for the CHB, a permanent dual-chamber pacemaker was inserted urgently. Initial blood investigations indicated an ongoing inflammatory process highlighting the possibility of myocarditis as a cause of the CHB. Therefore, a troponin level was taken and was noted to be elevated confirming the suspicion of myocarditis. The left ventricular ejection fraction (LVEF) decreased over the following days to approximately 20%, clinically resulting in pulmonary oedema and acute shortness of breath. The patient required aggressive intravenous diuresis and anti-heart failure medication. An endomyocardial biopsy (EMB) confirmed the diagnosis of lymphocytic myocarditis. The patient's condition improved secondary to an improvement in LVEF and resolution of the heart block. A cardiac magnetic resonance (CMR) imaging performed 6 weeks from admission reported an improved LVEF of 51% with no late gadolinium enhancement (LGE). Based on the reassuring CMR findings and the resolution of CHB on follow-up pacemaker checks, it was deemed safe to explant the pacemaker.

CONCLUSIONS

Acute myocarditis may be complicated with high-degree AV block and cardiogenic shock necessitating close observation in a critical care unit. A permanent pacemaker may provide atrio-ventricular synchrony which helps stabilise the patient's condition and protect from a prolonged period of heart block. Early myocardial fibrosis on EMB and degree of LGE on CMR are indicators of persistent atrioventricular block. Guideline-directed treatment of heart failure is essential.

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.

Diagnosis of cardiac sarcoidosis: histological evidence vs. imaging

INTRODUCTION

The prognosis for cardiac sarcoidosis (CS) remains unfavorable. Although early and accurate diagnosis is crucial, the low detection rate of endomyocardial biopsy makes accurate diagnosis challenging.

AREAS COVERED

The Heart Rhythm Society (HRS) consensus statement and the Japanese Circulation Society (JCS) guidelines are two major diagnostic criteria for the diagnosis of CS. While the requirement of positive histology for the diagnosis in the HRS criteria can result in overlooked cases, the JCS guidelines advocate for a group of 'clinical' diagnoses based on advanced imaging, including cardiovascular magnetic resonance and 18F-fluorodeoxyglucose positron emission tomography, which do not require histological evidence. Recent studies have supported the usefulness of clinical diagnosis of CS. However, other evidence suggests that clinical CS may sometimes be inaccurate. This article describes the advantages and disadvantages of the current diagnostic criteria for CS, and typical imaging and clinical courses.

EXPERT OPINION

The diagnosis of clinical CS has been made possible by recent developments in multimodality imaging. However, it is still crucial to look for histological signs of sarcoidosis in other organs in addition to the endomyocardium. Additionally, phenotyping based on clinical manifestations such as heart failure, conduction abnormality or ventricular arrhythmia, and extracardiac abnormalities is clinically significant.

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.

Cardiac magnetic resonance in giant cell myocarditis: a matched comparison with cardiac sarcoidosis

AIMS

Giant cell myocarditis (GCM) is an inflammatory cardiomyopathy akin to cardiac sarcoidosis (CS). We decided to study the findings of GCM on cardiac magnetic resonance (CMR) imaging and to compare GCM with CS.

METHODS AND RESULTS

CMR studies of 18 GCM patients were analyzed and compared with 18 CS controls matched for age, sex, left ventricular (LV) ejection fraction and presenting cardiac manifestations. The analysts were blinded to clinical data. On admission, the duration of symptoms (median) was 0.2 months in GCM vs. 2.4 months in CS (P = 0.002), cardiac troponin T was elevated (>50 ng/L) in 16/17 patients with GCM and in 2/16 with CS (P < 0.001), their respective median plasma B-type natriuretic propeptides measuring 4488 ng/L and 1223 ng/L (P = 0.011). On CMR imaging, LV diastolic volume was smaller in GCM (177 ± 32 mL vs. 211 ± 58 mL, P = 0.014) without other volumetric or wall thickness measurements differing between the groups. Every GCM patient had multifocal late gadolinium enhancement (LGE) in a distribution indistinguishable from CS both longitudinally, circumferentially, and radially across the LV segments. LGE mass averaged 17.4 ± 6.3% of LV mass in GCM vs 25.0 ± 13.4% in CS (P = 0.037). Involvement of insertion points extending across the septum into the right ventricular wall, the "hook sign" of CS, was present in 53% of GCM and 50% of CS.

CONCLUSION

In GCM, CMR findings are qualitatively indistinguishable from CS despite myocardial inflammation being clinically more acute and injurious. When matched for LV dysfunction and presenting features, LV size and LGE mass are smaller in GCM.

Eosinophilic myocarditis complicated by permanent atrioventricular nodal block: a case report

Background

Eosinophilic myocarditis (EM) is a rare disease with different clinical pictures and disease courses. Little literature is available on the various courses of the disease.

Case summary

A previously healthy 44-year-old male patient presented with acute heart failure and developed complete atrioventricular (AV) block requiring pacing. Acute heart failure was managed with inotropic support, non-invasive ventilation, and implantation of a permanent AV-sequential pacemaker. Cardiac magnetic resonance imaging was suggestive of myocarditis and endomyocardial biopsy diagnosed EM histologically. Endomyocardial biopsy was essential for definite aetiologic assignment, thus dispelling initial reservations about immunosuppressive therapy. Final treatment strategy consisted of steroids and Azathioprine.

Discussion

Endomyocardial biopsy is essential to establish diagnosis and targeted treatment in EM, which can rapidly lead to life-threatening conditions. Left ventricular function recovered within 2 weeks in response to immunosuppression and the patient was consistently well during follow-up. Despite the otherwise good response to immunosuppression, complete AV block continued over time.

Fulminant Giant Cell Myocarditis vs. Lymphocytic Myocarditis: A Comparison of Their Clinical Characteristics, Treatments, and Outcomes

Objectives: Fulminant myocarditis (FM) is a rapidly progressive and frequently fatal form of myocarditis that has been difficult to classify. This study aims to compare the clinical characteristics, treatments and outcomes in patients with fulminant giant cell myocarditis (FGCM) and fulminant lymphocytic myocarditis (FLM).

Methods and Results: In our retrospective study, nine patients with FGCM (mean age 47.9 ± 7.5 years, six female) and 7 FLM (mean age 42.1 ± 12.3 years, four female) patients confirmed by histology in the last 11 years were included. Most patients with FGCM and FLM were NYHA functional class IV (56 vs. 100%, p = 0.132). Patients with FGCM had significantly lower levels of high-sensitivity C-reactive protein [hs-CRP, 4.4 (2.0–10.2) mg/L vs. 13.6 (12.6–14.6) mg/L, P = 0.004, data shown as the median with IQR], creatine kinase-myoglobin [CK-MB, 1.4 (1.0–3.2) ng/ml vs. 14.6 (3.0–64.9) ng/ml, P = 0.025, median with IQR], and alanine aminotransferase [ALT, 38.0 (25.0–61.5) IU/L vs. 997.0 (50.0–3,080.0) IU/L, P = 0.030, median with IQR] and greater right ventricular end-diastolic diameter (RVEDD) [2.9 ± 0.3 cm vs. 2.4 ± 0.6 cm, P = 0.034, mean ± SD] than those with FLM. No differences were observed in the use of intra-aortic balloon pump (44 vs. 43%, p = 1.000) and extracorporeal membrane oxygenation (11 vs. 43%, p = 0.262) between the two groups. The long-term survival rate was significantly lower in FGCM group compared with FLM group (0 vs. 71.4%, p = 0.022). A multivariate cox regression analysis showed the level of hs-CRP (hazard ratio = 0.871, 95% confidence interval: 0.761–0.996, P = 0.043) was an independent prognostic factor for FM patients. Furthermore, the level of hs-CRP had a good ability to discriminate between patients with FGCM and FLM (AUC = 0.94, 95% confidence interval: 0.4213–0.9964).

Conclusions: The inflammatory response and myocardial damage in the patients with FGCM were milder than those with FLM. Patients with FGCM had distinctly poorer prognoses compared with those with FLM. Our results suggest that hs-CRP could be a promising prognostic biomarker and a hs-CRP level of 11.71 mg/L is an appropriate cutoff point for the differentiating diagnosis between patients with FGCM and FLM.

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 immune-inflammation index as a tool for predicting the need for a permanent pacemaker in patients with drug-induced atrioventricular block

BACKGROUND

Drug-induced atrioventricular block (AVB) is generally considered reversible and does not require a permanent pacemaker implantation (PPM). However, some studies have demonstrated a failure of AVB cessation even when the inducing agent has been discontinued. This study has investigated the use of systemic immune-inflammation index (SII) to predict irreversible drug-induced AVB after drug discontinuation.

METHOD

Files of patients with high-degree AVB that required a temporary pacemaker (TPM) were retrospectively analyzed. Sixty-three patients in which AVB was drug-induced were included in the study. The patients were divided into the following two groups: (1) those whose AVB reversed after discontinuation of the related drug, and (2) those in which AVB did not reverse.

RESULTS

AVB reversed in 24 patients (38%) after the inducing agent was discontinued while in the remaining 39 patients (62%) PPM was required. The most common drugs to induce AVB were beta-blockers (n = 46, 73%). Follow-up time with TPM was significantly longer in the irreversible group (2.91 ± 1.05 days vs. 4.94 ± 2.15 days, p < .001). Multivariate logistic regression analysis showed that SII (odds ratio [OR] = 1.002; 95% confidence interval [CI] = 1.000-1.003; p = .01) was an independent predictor of the requirement for a PPM. An SII > 752.05 was found to be a predictor of irreversible AVB requiring PPM with a sensitivity of 64% and specificity of 75% (receiving-operating characteristics [ROC] area under the ROC curve [AUC]: 0.704, 95% CI = 0.570-0.838, p = .007).

CONCLUSION

Approximately 2/3 of drug-induced high-degree AVBs are irreversible. SII is an easily available and cheap inflammatory biomarker that can be used to predict irreversible AVB.

A case of lymphocytic myocarditis with complete heart block requiring permanent pacemaker implantation

Lymphocytic myocarditis (LM) is a rare condition with a broad spectrum of clinical presentations. Complete heart block (CHB) is an uncommon sequela. We present a case of a young man with biopsy proven LM who presented with cardiogenic shock and went on to develop non-resolving CHB requiring permanent pacemaker implantation.

Manifestations and Outcome of Cardiac Sarcoidosis and Idiopathic Giant Cell Myocarditis by 25-Year Nationwide Cohorts

Background Cardiac sarcoidosis (CS) and giant cell myocarditis (GCM) share many histopathologic and clinical features. Whether they are parts of a one-disease continuum has been discussed. Methods and Results We compared medical record data of 351 CS and 28 GCM cases diagnosed in Finland since the late 1980s and followed until February 2018 for a composite end point of cardiac death, aborted sudden death, and heart transplantation. Heart failure was the presenting manifestation in 50% versus 15% (P<0.001), and high-grade atrioventricular block in 21% versus 43% (P=0.044), of GCM and CS, respectively. At presentation, left ventricular ejection fraction was ≤50% in 81% of cases of GCM versus in 48% of CS (P=0.004). The median (interquartile range) of plasma NT-proBNP (N-terminal pro-B-type natriuretic peptide) was 5273 (2782-11309) ng/L on admission in GCM versus 859 (290-1950) ng/L in CS (P<0.001), and cardiac troponin T exceeded 50 ng/L in 17 of 19 cases of GCM versus in 48 of 239 cases of CS (P<0.001). The 5-year estimate of event-free survival was 77% (95% CI, 72%-82%) in CS versus 27% (95% CI, 10%-45%) in GCM (P<0.001). By Cox regression analysis, GCM predicted cardiac events with a hazard ratio of 5.16 (95% CI, 2.82-9.45), which, however, decreased to 1.58 (95% CI, 0.71-3.52) after inclusion of markers of myocardial injury and dysfunction in the model. Conclusions GCM differs from CS in presenting with more extensive myocardial injury and having worse long-term outcome. Yet the key determinant of prognosis appears to be the extent of myocardial injury rather than the histopathologic diagnosis.

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.

Efficacy of immunosuppressive therapy in myocarditis: A 30-year systematic review and meta analysis

AIMS

Myocarditis is an inflammation of the heart muscle, due to infectious, toxic or autoimmune causes. Literature reported controversial results in relation to the effect of immunosuppression (IS)/immunomodulation (IM). We aimed at assessing the effect of IS/IM by meta analysis.

METHODS AND RESULTS

Using the P.R.I.S.M.A. approach, two researchers searched for relevant studies on PubMed, Embase, and the Central Registry of Controlled Trials of the Cochrane Library. Proposed MeSH terms were: "immunotherapy OR immune therapy OR immune modeling OR Immunosuppressive Agents" AND "combination OR combined with OR plus" AND "myocarditis OR cardiomyopathies OR inflammatory cardiomyopathy". The language was restricted to English. Reference lists of included articles and those relevant to the topic were hand searched for the identification of additional, potentially relevant articles. The cutoff date was from 1987 until 30th Nov 2019. Reported survival or mortality events or change of left ventricular ejection fraction (LVEF) after IS/IT were primary outcomes of the study; in addition, improvement of New York Heart Association class, follow-up biopsy (Bx) findings, viral genome clearance on Bx and recurrence of myocarditis were recorded if reported. Statistical analysis was conducted using Review Manager 5.3; 5452 studies were screened, of these 73 were assessed for eligibility, including 8 randomized control studies, 26 retrospective studies, 2 prospective studies and 1 case control study, 34 case reports and 2 case series. In prospective studies, the difference in mortality between the IS and control groups tended to be lower in the combined IS groups (12.5% vs. 18.2%) (95% CI of odds ratio 0.7(0.3, 1.64)) and the pooled difference of the increase of LVEF between the IS and control groups tended to be higher in the combined IS groups (95% CI 7.26 (-2.29, 16.81)). In retrospective studies, the difference of survival between the IS and control group was significantly in favor of IS (95%CI Hazard ratio 0.82(0.69, 0.96)).

CONCLUSIONS

A tailored IS may be considered in myocarditis, depending on the phase of the disease, and the type of underlying autoimmune or immune-mediated form.

Idiopathic giant cell myocarditis or cardiac sarcoidosis? A retrospective audit of a nationwide case series

Aims

Cardiac sarcoidosis (CS) and giant cell myocarditis (GCM) are inflammatory cardiomyopathies sharing histopathological and clinical features. Their differentiation is difficult and susceptible of confusion and apparent mistakes. The possibility that they represent different phenotypes of a single disease has been debated.

Methods and results

We made a retrospective audit of 73 cases of GCM diagnosed in Finland since the late 1980s. All available histological material was reanalyzed as were other examinations pertinent to the distinction between GCM and CS. Finding granulomas in or outside the heart was considered diagnostic of CS and exclusive of GCM. Altogether 45 of the 73 cases of GCM (62%) were reclassified as CS. In all except one case, this was based on finding sarcoid granulomas that either had been originally missed (n = 29) or misinterpreted (n = 11) or were found in additional posttransplant myocardial specimens (n = 3) or samples of extracardiac tissue (n = 1) accrued over the disease course. Supporting the reclassification, patients relocated to the CS group had less heart failure at presentation (prevalence 20% vs. 46%, P = 0.017) and better 1 year transplant‐free survival (82% vs. 45%, P = 0.011) than patients considered to represent true GCM.

Conclusions

Recognizing granulomas in or outside the heart remains a challenge for the pathologist. Given that CS and GCM are considered distinct diseases and granulomas exclusive of GCM, many cases of GCM, if thoroughly scrutinized, may need reclassification as CS. However, whether CS and GCM are truly different entities or parts of a one‐disease continuum has not yet been conclusively settled.

A giant mystery in giant cell myocarditis: navigating diagnosis, immunosuppression, and mechanical circulatory support

Giant cell myocarditis is a rare but often devastating diagnosis. Advances in cardiac imaging and mechanical circulatory support have led to earlier and more frequent diagnoses and successful management. This disease state has wide variation in acuity of presentation, and consequently, optimal treatment ranging from intensity and type of immunosuppression to mechanical circulatory support is not well defined. The following case describes the management of a patient with an unusual presentation of giant cell myocarditis over a 10 year course of advanced heart failure therapies and immunomodulatory support. This case highlights emerging concepts in the management of giant cell myocarditis including sub‐acute presentations, challenges in diagnosis, and treatment modalities in the modern era.

Myocarditis: somethings old and something new

"Since the pathological conditions take place at the cellular level, viral myocarditis and postinfectious autoimmunity can be suggested but not diagnosed clinically. All clinical methods including imaging techniques are misleading if infectious agents are involved. Accurate diagnosis demands simultaneous histologic, immunohistochemical, and molecular biological workup of the tissue. If the primary infectious or immune-mediated causes of the disease are carefully defined by clinical and biopsy-based tools, specific antiviral treatment options in addition to basic symptomatic therapy are available under certain conditions. These may allow a tailored cause-specific treatment that improves symptoms and prognosis of patients with acute and chronic disease." Uwe Kühl; Heinz-Peter SchultheissViral myocarditis.Swiss Medical Weekly. 144():w14010, JAN 2014 DOI:10.4414/smw.2014.14010.

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.

Acute necrotizing eosinophilic myocarditis complicated by complete atrioventricular block promptly responded to glucocorticoid therapy

Acute myocarditis is frequently accompanied with conduction disturbances. Complete atrioventricular (AV) block may occur in acute myocarditis, but rarely in eosinophilic myocarditis. Acute necrotizing eosinophilic myocarditis, the most severe form of eosinophilic myocarditis, is generally fatal, and rarely complicated by complete AV block. We report a case of a 66-year-old woman with acute necrotizing eosinophilic myocarditis who presented with general malaise and nausea. She suddenly fell into cardiogenic shock because of complete AV block and worsened heart failure. Ultrasound cardiography revealed pericardial effusion, edematous myocardium, and reduced contractility of the left ventricle. The biopsied specimens showed marked interstitial infiltration with predominant eosinophils accompanied with myocardial necrosis. Oral administration of glucocorticoid in moderate dose promptly resolved the complete AV block, her clinical symptoms, and cardiac function. We recognized that acute necrotizing eosinophilic myocarditis can be complicated by complete AV block. Steroid therapy could be effective in the treatment of conduction disturbance as well as myocardial inflammation. <Learning objective: We experienced a case of acute necrotizing eosinophilic myocarditis complicated by complete atrioventricular block. This case report documents the rare complication of acute necrotizing eosinophilic myocarditis and the great benefit of early steroid therapy for the condition.>.

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.

Idiopathic giant cell myocarditis in childhood: A case report

Idiopathic giant cell myocarditis is a rare entity of unknown origin, which causes sudden death in more than half of the affected patients. It is rarely seen in childhood, and might result in death due to heart failure and ventricular arrhythmias. Idiopathic giant cell myocarditis is mostly diagnosed at autopsy incidentally. Here we present a rare case of childhood idiopathic giant cell myocarditis. A 10-year old boy found dead in his bed in the morning. Interview with family members revealed death the boy was in good health conditions apart from being overweight. At autopsy, external examination was completely normal. Internal examination revealed normal findings; the heart was 297g and macroscopically normal. No traces of any toxic agents detected in complete toxicological analyses. Areas characterized with granulomatous lesions, lymphocytes, histiocytes, and multinucleated giant cells were observed in myocardium at histopathological examination. No necrosis was observed in granulomatous areas. Tuberculosis was negative in the PCR assays. There were no signs indicative of fungal infection, and clinical status of the case was not compatible with the sarcoidosis. In this respect death was attributed to idiopathic giant cell myocarditis.

When should we consider the diagnosis of giant cell myocarditis? Revisiting "classic" echocardiographic and clinical features of this rare pathology

OBJECTIVES

Giant cell myocarditis is a rare and often fatal disorder. According to the American Heart Association, the American College of Cardiology Foundation, and the European Society of Cardiology scientific statements, an endomyocardial biopsy should be done to exclude giant cell myocarditis in unexplained new-onset heart failure of 2 weeks to 3 months duration associated with dilated left ventricle and new ventricular arrhythmias, or Mobitz type II second-degree, or third-degree atrioventricular heart block.

CASE PRESENTATIONS

Two hundred thirty-five heart transplants were performed since May 1993 at the Institut universitaire de cardiologie et de pneumologie de Quebec, Canada. Giant cell myocarditis was found in the explanted hearts of 5 patients. The preoperative diagnosis of giant cell myocarditis was done by endomyocardial biopsy or at the installation of a left ventricular-assisted device. Patients had symptoms of progressive heart failure of subacute onset. Patients consulted at a mean 32 days after the onset of symptoms. Two patients neither had ventricular arrhythmia nor heart block. Two patients had ventricular arrhythmias and heart block; the other patient had symptomatic heart block. All patients had at least 2 echocardiographies. Two patients had an increase in left ventricular size, enough to reach the criteria of left ventricular dilatation according to the American Society of Echocardiography. During this time, left ventricular ejection fraction showed a rapid decline (mean 37% to 16%).

CONCLUSIONS

Ventricular arrhythmia, heart block, and left ventricular dilatation initially can be absent in many patients having giant cell myocarditis with symptoms of progressive heart failure. Endo-myocardial biopsy should be quickly considered in patients with a rapid and dramatic decline of left ventricular ejection fraction, even in the absence of classic clinical and echocardiographic features of giant cell myocarditis to rapidly obtain the diagnosis of this rare but lethal disease.

Recurrent lymphocytic myocarditis in a young male with ulcerative colitis

Awareness of myocarditis in association with inflammatory bowel diseases is crucial as it bears a rare but serious risk for mortality. This report describes the case of a young Caucasian male, whose heart biopsy was tested negative for giant cells and bacterial or viral genomes or proteins. He was experiencing severe lymphocytic myocarditis (other than mesalamine-induced) along with cardiogenic shock during ulcerative colitis exacerbation. This is an extremely rare, if not unique, clinical constellation. We chose to study the epidemiologic grounds and all major aspects of differential pathogenesis and treatment of this serious health problem.

Virus-Negative Active Lymphocytic Myocarditis Progressing to a Fibrotic Stage

We report a fairly special case of lymphocytic myocarditis progressing to a fibrotic stage, described using multimodality imaging and confirmed on histopathology. This paper presents an uncommon diagnosis with a probable guarded prognosis.

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.

Sudden Cardiac Death due to Giant Cell Inflammatory Processes

Granulomatous inflammation of the myocardium may occur in a number of systemic disease processes including those with infectious etiologies such as fungal, mycobacterial and parasitic infections, as well as hypersensitivity reactions, and rarely autoimmune disorders. In many of these disorders, giant cells are components of the inflammatory infiltrate. Systemic granulomatous processes of unknown pathogenesis, most notably sarcoidosis, may also be associated with involvement of the myocardium. Occasionally, these disorders are associated with sudden death due to pathologic involvement of the heart. In contrast, giant cell myocarditis, also known as idiopathic myocarditis, a rare, frequently fulminant and fatal disorder of unknown etiology, is isolated to the heart and lacks systemic involvement. This disorder is most commonly diagnosed at autopsy. We present two cases in which sudden death resulted from a giant cell inflammatory process affecting the myocardium. Both individuals lacked antemortem diagnoses and collapsed at their respective places of employment. These cases compare and contrast the clinical and pathologic issues involved in the differential diagnoses of the subgroup of sudden cardiac deaths resulting from giant cell inflammatory processes that affect the myocardium, as well as the value of histologic examination and immunohistochemical studies.

Myocarditis

Viruses are the most common cause of myocarditis in economically advanced countries.

Enteroviruses and adenoviruses are the most common etiologic agents.

Viral myocarditis is a triphasic process. Phase 1 is the period of active viral replication in the myocardium during which the symptoms of myocardial damage range from none to cardiogenic shock. If the disease process continues, it enters phase 2, which is characterized by autoimmunity triggered by viral and myocardial proteins. Heart failure often appears for the first time in phase 2. Phase 3, dilated cardiomyopathy, is the end result in some patients. Diagnostic procedures and treatment should be tailored to the phase of disease.

Viral myocarditis is a significant cause of dilated cardiomyopathy, as proved by the frequent presence of viral genomic material in the myocardium, and by improvement in ventricular function by immunomodulatory therapy.

Myocarditis of any etiology usually presents with heart failure, but the second most common presentation is ventricular arrhythmia. As a result, myocarditis is one of the most common causes of sudden death in young people and others without preexisting structural heart disease.

Myocarditis can be definitively diagnosed by endomyocardial biopsy. However, it is clear that existing criteria for the histologic diagnosis need to be refined, and that a variety of molecular markers in the myocardium and the circulation can be used to establish the diagnosis.

Treatment of myocarditis has been generally disappointing. Accurate staging of the disease will undoubtedly improve treatment in the future. It is clear that immunosuppression and immunomodulation are effective in some patients, especially during phase 2, but may not be as useful in phases 1 and 3. Since myocarditis is often selflimited, bridging and recovery therapy with circulatory assistance may be effective. Prevention by immunization or receptor blocking strategies is under development.

Giant cell myocarditis is an unusually fulminant form of the disease that progresses rapidly to heart failure or sudden death. Rapid onset of disease in young people, especially those with other autoimmune manifestations, accompanied by heart failure or ventricular arrhythmias, suggests giant cell myocarditis.

Peripartum cardiomyopathy in economically developed countries is usually the result of 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.

A clinical and histopathologic comparison of cardiac sarcoidosis and idiopathic giant cell myocarditis

OBJECTIVES

The goal of this study was to determine the prognostic value of clinical data available at presentation and histology in cardiac sarcoidosis (CS) and idiopathic giant cell myocarditis (IGCM).

BACKGROUND

The prognosis of patients with nonischemic cardiomyopathy is partly dependent on the histologic diagnosis. Survival in IGCM is poor. The prognosis of a histologically related entity, cardiac sarcoidosis (CS), is less well established, and the prognostic value of the distinction between CS and IGCM on endomyocardial biopsy (EMB) is unknown.

METHODS

We identified 115 patients from the Multicenter IGCM Registry with CS (n = 42) and IGCM (n = 73). We compared the clinical data for these two groups using Cox proportional-hazards models to assess the association between histologic diagnosis and survival. In order to determine whether histologic features could reliably differentiate these two entities, two cardiac pathologists semiquantitatively graded the inflammatory infiltrate components and compared the results between groups.

RESULTS

Black race was more frequent in the CS group (31% vs. 4%, p < 0.0001). Syncope and atrioventricular block were also more frequently observed in CS than IGCM (31% vs. 5%, p = 0.0002 and 50% vs. 15%, p < 0.0001, respectively). Left-sided heart failure was more common in IGCM (40% vs. 64%, p = 0.013). In CS patients diagnosed by EMB, the five-year transplant-free survival after diagnosis was 69.8% versus 21.9% for IGCM (p < 0.0001, log-rank test). In multivariate models, presentation with heart failure predicted IGCM, and presentation with heart block or more than nine weeks of symptoms predicted CS. Eosinophils, myocyte damage, and foci of lymphocytic myocarditis were more frequent in IGCM, while granulomas and fibrosis were more frequent in CS.

CONCLUSIONS

Transplant-free survival is better for patients with CS than for IGCM diagnosed by EMB. Presentation with heart failure predicted IGCM, and presentation with heart block or more than nine weeks of symptoms predicted CS.

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.

Electrical remodeling of the ventricular myocardium in myocarditis: studies of rat experimental autoimmune myocarditis

The purpose of this study was to evaluate the electrical remodeling of the ventricular myocardium in the experimental autoimmune myocarditis (EAM) model in Lewis rats. EAM was induced by immunization with cardiac myosin. During the active myocarditis phase, the effective refractory period (ERP), the duration of the monophasic action potential (MAPD) was extracted from the left ventricular free wall, and the mRNA levels of Kv1.4, 4.2, 4.3 and L type Ca2+ channel were determined by RNase protection assays. The inducibility of ventricular arrhythmia was higher in EAM rats than in the control rat, and the direct relationship between the coupling intervals of the premature stimulus and the ventricular arrhythmia in EAM rats. The ERP was prolonged in EAM rats compared with the control group. The MAPDs determined as 20% and 90% repolarization time, were both longer in EAM rats than in the controls. The level of expression of Kv4.2 mRNA was reduced in EAM rats in comparison with the controls, whereas those of Kv1.4, 4.3 and the L type Ca2+ channel were unchanged. Ventricular vulnerability was higher in EAM rats than in the control rats, and some of the ventricular arrhythmias observed in the EAM group seemed to be based on triggered activity. The level of expression of Kv4.2 mRNA was significantly reduced, and this change was compatible with prolongation of the action potential duration.

Giant cell myocarditis in a 12-year-old girl with common variable immunodeficiency

Giant cell myocarditis (GCM) is a rare and often fatal disease that infrequently affects children. Common variable immunodeficiency (CVID) describes a heterogeneous group of disorders characterized by hypogammaglobulinemia and poor specific antibody responses. To our knowledge, CVID and GCM have not been reported together in 1 patient. We describe a 12-year-old girl with CVID who developed acute severe GCM that necessitated cardiac transplantation. Histopathological and immunohistochemical studies of the endomyocardial biopsy specimen and the explanted heart revealed numerous histiocytes, eosinophils, T cells, and multinucleated giant cells. Both CVID and GCM are thought to involve dysregulation of T-cell function and have been associated with a similar spectrum of autoimmune conditions. The coincidence of CVID and GCM in a single patient may reflect a pathophysiologic connection.

Early and long-term mortality of the clinical subtypes of myocarditis

The frequency of myocarditis and the prognosis for patients remains uncertain and, moreover, the clinical classification of myocarditis is controversial. From 1985 to 2000, 71 adult patients with clinically suspected myocarditis were admitted to 11 cardiovascular centers. Of these, 48 cases had histology proven myocarditis: 41 cases of lymphocytic myocarditis, 6 of giant cell myocarditis and 1 of eosinophilic myocarditis. Myocarditis was classified as acute (30 cases) or chronic (18 cases) according to the onset of the disease, and acute myocarditis was further categorized into common or fulminant type depending on whether or not patients required mechanical circulatory support in the management of heart failure (9 and 21 cases, respectively). Chronic myocarditis was divided into 3 subgroups: a persistent type lasting over 3 months after distinct onset (3 cases), a recurrent type (2 cases) and a latent form (13 cases). The early mortality of these 5 subtypes of myocarditis were acute common 22%, acute fluminant 43%, chronic persistent 33%, chronic recurrent 50%, and chronic latent 38%. The overall early mortality of all patients with myocarditis was 38% in spite of aggressive treatment during hospitalization. On the other hand, the long-term prognosis of patients with myocarditis was favorable; only 4 cases, who survived the active phase, died in the late phase: 1 had fulminant myocarditis and the other 3 had the chronic latent form. Thus, the early mortality of patients with myocarditis was very high regardless of the subtype, but if patients can survive the active phase, they have a favorable prognosis except with the chronic latent form.