SHM Converge Scientific Abstract ePoster Gallery-Twin Diseases: A Case of Cardiomyopathy Resembling Cardiac Sarcoidosis- Histologically Confirmed as Giant Cell Myocarditis

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This case report describes a 56-year-old previously healthy woman who initially presented with syncope, seizure-like activity, and arrhythmias including paroxysmal SVT, ventricular tachycardia, and complete heart block. She later developed chest pain, a new left bundle branch block, and elevated troponin. Cardiac catheterization showed non-obstructive coronary disease and reduced left ventricular ejection fraction (30–35%). Cardiac MRI revealed heterogeneous late gadolinium enhancement strongly suggestive of cardiac sarcoidosis, so she was treated with an ICD, high-dose prednisone, and amiodarone.<br /><br />Despite treatment, she rapidly worsened. Within a week she developed volume overload, then refractory VT storm, followed by cardiogenic shock requiring intra-aortic balloon pump support, ventilation, inotropes, ECMO, and ultimately orthotopic heart transplantation. Histology of the explanted heart showed myocyte dropout, granulation tissue, hemosiderin-laden macrophages, and T-cells, consistent with resolving giant cell myocarditis (GCM), with no evidence of cardiac sarcoidosis (CS).<br /><br />The report emphasizes that GCM and CS have major clinical and imaging overlap, especially on cardiac MRI and PET, but are distinct diseases. GCM typically progresses rapidly with severe heart failure and poor prognosis, while CS more often presents with conduction disease, arrhythmias, and slower progression. Definitive diagnosis requires endomyocardial biopsy. Histologic clues favoring GCM include disproportionate necrosis relative to inflammation and absence of well-formed granulomas; granulomas support CS.<br /><br />The authors conclude that early differentiation is critical because treatment and prognosis differ: CS is usually managed with prednisone, whereas GCM often requires steroid-sparing immunosuppressive therapy and may progress to transplant.

Asset Subtitle

Anam Ahmad

Meta Tag

Author List Anam Ahmad, Balakrishna Ravella, Chinenye Udokwu, Edward J. Hurley, Keith A. Bernstein

Category Clinical Vignettes

Concept Giant Cell Myocarditis

Concept Cardiac Sarcoidosis

Concept Cardiac Biopsy

Concept Corticosteroids

Concept Nonischemic Cardiomyopathy

Distinguished Non-Finalist

Presenter Organization St. Lukes Hospital Chesterfield Missouri

Presenting Author Anam Ahmad

Track Adult

Keywords

giant cell myocarditis

cardiac sarcoidosis

ventricular tachycardia

complete heart block

cardiogenic shock

cardiac MRI

late gadolinium enhancement

endomyocardial biopsy

heart transplantation

immunosuppressive therapy

Giant Cell Myocarditis

Cardiac Sarcoidosis

Cardiac Biopsy

Corticosteroids

Nonischemic Cardiomyopathy