Pediatric myocarditis has a mortality of at least 25%. Identification of children with myocarditis in the early phases is essential in order to start monitoring and supportive treatment in a timely manner, but diagnosis in the ED is challenging due to the heterogeneous and unspecific clinical presentation. Most patients (59%) required two or more visits to the ED before the diagnosis of myocarditis. A previous diagnosis different from myocarditis was made in 52% of cases. 31% were categorized as respiratory infection (bronchiolitis, pneumonia, and upper respiratory tract infection), 17% as gastrointestinal infection, 2% as urinary tract infection, and 2% as infantile colic.