Atrial giant cell myocarditis is a distinct clinicopathologic entity presenting with atrial dilatation and wall thickening, and follows a more benign course than classic ventricular GCM.
Case Report (n=6)
Atrial giant cell myocarditis is a distinct clinicopathologic entity that presents with atrial dilatation and has a more favorable prognosis than classic ventricular giant cell myocarditis.
BACKGROUND: Giant cell myocarditis (GCM) typically causes fulminant heart failure, arrhythmias, or heart block, necessitating aggressive immunosuppression, ventricular assist device insertion, or cardiac transplantation. We describe a novel variant of GCM, primarily involving the atria, that displays distinctive clinical features and follows a more benign course than ventricular GCM. METHODS AND RESULTS: We identified 6 patients (median age 67.5 years, 4 male) with atrial GCM in our pathology consultation practices from 2010 to 2012. Clinical history, imaging, and pathology materials were reviewed. Clinically, 4 patients had atrial fibrillation, 1 had acute heart failure, and 1 had incidental disease at autopsy. Among the 5 living patients, echocardiography revealed severe atrial dilatation (5 cases), mitral/tricuspid regurgitation (5), atrial mural thrombus (3), atrial wall thickening (2), and atrial hypokinesis (2). Ventricular function was preserved in all 5. Histological review of surgically resected atria showed giant cell and lymphocytic infiltrates, lymphocytic myocarditis-like foci, cardiomyocyte necrosis, and cardiomyocyte hypertrophy in all cases. Other features included interstitial fibrosis (5), poorly-formed granulomas (4), eosinophils (4), neutrophils (1), and vasculitis (1). Treatment consisted of steroids and cyclosporine (1), pacemaker placement for sick sinus syndrome (1), and supportive care (3). All 5 living patients returned to baseline exercise tolerance after 6 to 16 weeks of follow-up. CONCLUSIONS: Atrial GCM represents a distinct clinicopathologic entity with a more favorable prognosis than classic ventricular GCM. This disorder should be included in the differential diagnosis of atrial dilatation, particularly when associated with atrial wall thickening. The utility of immunomodulatory therapy for this condition remains unknown.
Larsen et al. (Tue,) conducted a case report in Atrial giant cell myocarditis (n=6). Atrial giant cell myocarditis was evaluated on Clinical features and prognosis. Atrial giant cell myocarditis is a distinct clinicopathologic entity presenting with atrial dilatation and wall thickening, and follows a more benign course than classic ventricular GCM.