Giant Cell Myocarditis in Children.

Giant cell myocarditis is a rare cause of heart failure and arrhythmias in children. In the multicenter GCM registry, 4 of 63 cases (6%) occurred in subjects less than age 19. In this manuscript, these 4 cases are summarized and the findings related to other published reports. Unlike pediatric lymphocytic myocarditis, that generally has a good prognosis despite a fulminant clinical course, GCM usually results in death or heart transplantation. In children as in adults, GCM can often be distinguished clinically by a failure to respond to usual care and the frequent occurrence of ventricular arrhythmias or heart block in the setting of acute cardiomyopathy. GCM is also associated with other immune-mediated disorders in about 20% of patients. In children associated immune-mediated disorders have only been observed in females. Prompt endomyocardial biopsy in the setting of suspected GCM can affect choice of mechanical circulatory support (MCS), lead to early listing for cardiac transplantation, and consideration of cyclosporine-based immunosuppression.