Viral myocarditis is a diagnosis of exclusion, and its main diagnostic criteria include: 1. history: 1-3 weeks before the onset of the disease, there is a history of pre-infection, such as a history of upper respiratory tract infection or intestinal infection; 2. clinical manifestations: symptoms of upper respiratory tract infection or intestinal infection in the early stage; symptoms of heart damage in the later stage, such as chest tightness, shortness of breath, palpitations; 3. laboratory tests: blood tests see a significant increase in cardiac enzymes CK, CKMB or troponin.