Complete remission of giant cell myocarditis by prednisolone monotherapy: A case with mild inflammation demonstrated by mismatch between T2-high intensity areas and late gadolinium enhancement.

Giant cell myocarditis (GCM) is a potentially lethal subtype of myocarditis. Herein, we report a case of a 22-year-old woman with GCM who was successfully treated with prednisolone monotherapy. The patient had a fever and shortness of breath and was referred to our hospital. Laboratory test results revealed elevated troponin I levels. Cardiac magnetic resonance (CMR) showed high intensity in the inferoseptal segment of the left ventricle on T2-weighted short tau inversion recovery imaging without late gadolinium enhancement (LGE), suggesting predominant edema rather than necrosis. The patient was diagnosed with GCM based on an endomyocardial biopsy, which revealed lymphocyte infiltration and multinucleated giant cells in the absence of granuloma formation. Subsequently, the patient received intravenous methylprednisolone at 1000 mg/day for 3 days followed by oral prednisolone at 30 mg/day, which normalized troponin levels. Follow-up CMR revealed improved cardiac inflammation; therefore, the patient was discharged without prescribing another immunosuppressive agent. Prednisolone was tapered and terminated three years after discharge. The patient went one year without medication and had no recurrence of GCM on follow-up. This case highlights the presence of mild GCM, successfully treated by steroid monotherapy, in which the mismatch between high-intensity T2 areas and LGE suggests mild inflammation. Learning objective: Giant cell myocarditis (GCM) is potentially lethal and usually requires multiple immunosuppressive agents. Here, we report a patient with GCM with preserved left ventricular ejection fraction. Cardiac magnetic resonance revealed focal high T2 signal intensity areas without late gadolinium enhancement, indicating myocardial edema without necrosis. The patient remained in remission with prednisolone monotherapy for 2 years. Our report indicates that "mild" GCM may be treated with prednisolone monotherapy.

The Clinical and Histological Intersection of Cardiac Sarcoidosis and Giant Cell Myocarditis.

The clinical and imaging features of cardiac sarcoidosis (CS) and giant cell myocarditis (GCM) are occasionally indistinguishable. This is a case of heart block and ventricular tachycardia where cardiac MRI, fluorodeoxyglucose positron emission tomography (FDG-PET) and biopsy revealed intermediate clinicohistologic phenotype between CS and GCM. This highlights gaps in the management of overlap conditions.

Giant cell myocarditis attributable to myositis: therapeutic management under the guidance of serial endomyocardial biopsy-a case report.

Background: Giant cell myocarditis is a fatal disease that could be rapidly progressive if not properly managed. However, the role of immunosuppressive therapy, especially in refractory cases, remains unclear. Case summary: A 76-year-old man presented with back pain with elevated cardiac enzymes. Skeletal muscle and endomyocardial biopsies revealed giant cell myositis and giant cell myocarditis. Despite the initial immunosuppressive therapy, cardiac enzymes continued to rise. Serial endomyocardial biopsies enabled combination treatment of prednisolone, cyclosporine, and mycophenolate mofetil according to histological inflammatory activity. Discussion: We presented a case of refractory giant cell myocarditis preceded by giant cell myositis. While endomyocardial biopsy is an approach with risk of procedural complications, it can guide giant cell myocarditis management when the initial immunosuppressive therapy is ineffective.

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.

Temporary mechanical circulatory support as a bridge to durable left ventricular assist device as destination therapy in fulminant giant cell myocarditis：A case report.

Fulminant giant cell myocarditis is a fatal form of acute myocarditis leading to a rapid-onset clinical presentation with lethal arrhythmias, acute heart failure, or cardiogenic shock requiring mechanical circulatory support. We report the case of a 52-year-old female diagnosed with fulminant myocarditis requiring veno-arterial extracorporeal membrane oxygenation (V-A ECMO) and intra-aortic balloon pump(IABP) support. Due to hemodynamic instability, she was transferred to our hospital by helicopter on day 4. On arrival at our hospital, she underwent percutaneous balloon atrial septostomy to decompress the left ventricle. Although the left ventricular distension and pulmonary edema improved after atrial septostomy, no signs of biventricular function recovery were identified on day 14. On day 23, V-A ECMO and IABP were switched to a durable left ventricular assist device(LVAD) system and a right ventricular assist device(RVAD) with ECMO (RVAD-ECMO) under median sternotomy. On day 37, RVAD-ECMO was eventually removed and rehabilitation was started with the remaining LVAD support as destination therapy. On day 78, the patient was finally discharged with LVAD support to follow-up as an outpatient. This case underscores the importance of a multidisciplinary approach and rigorous monitoring to optimize outcomes in the treatment of fulminant giant cell myocarditis.

A case report of giant cell myocarditis complicated by severe heart failure: the value of early endomyocardial biopsy and mechanical circulatory support.

Background: Giant cell myocarditis (GCM) is a rare, probably underdiagnosed and potentially fatal disease in young and middle-aged patients. Disease progression is often rapid, and life-threatening arrhythmias and cardiogenic shock due to progressive left ventricular failure are among the most feared complications. Although cardiac biomarkers and multimodality imaging are used as initial diagnostic tests in most patients, endomyocardial biopsy (EMB) is often required for a definitive diagnosis. However, there are still gaps in our knowledge in terms of the etiology, early diagnosis, management and prognosis of GCM. Case Description: We present the case of a male patient in his early 50s admitted to Haukeland University Hospital with fulminant GCM. He had no significant medical history in the past apart from hypertension, and presented to hospital in cardiogenic shock after a few weeks of progressive shortness of breath. Rapid initiation of methylprednisolone had an immediate effect on reducing myocardial inflammation, and sustained treatment with a combination of immunosuppressive agents along with optimal heart failure medications led to complete recovery of the heart function and clinical remission over several years. The case study highlights the urgency of an early EMB, access to mechanical circulatory support (MCS) and the efficacy of immunosuppressive treatment and optimal medical management for heart failure. Finally, our review of the literature also provides an updated guidance on the contemporary management of GCM patients. Conclusions: Accurate and early diagnosis with EMB in patients with GCM are crucial for better outcomes. Rapid initiation of methylprednisolone reduces myocardial inflammation and the risk of death. Sustained treatment with a combination of immunosuppressive agents together with optimal heart failure medications are essential for myocardial recovery and long-term stabilization. The use of MCS is the cornerstone in the management of GCM with a clear survival benefit.