The clinical manifestations of myocarditis in patients depend on the extent and location of the lesion. Mild cases may have no symptoms at all, while severe cases can even present with heart failure and shock. Most patients have precursor symptoms of viral infection one to three weeks before the onset, such as fever, general fatigue, and muscle soreness. Some patients have gastrointestinal symptoms like nausea and vomiting. Subsequently, they may experience palpitations, chest pain, breathing difficulties, edema, and even fainting or sudden death. The majority of clinically diagnosed myocarditis cases primarily present with or are primarily symptomatic of psychological frailty. A minority of patients may experience fainting or Aschner's syndrome as a result.