Fulminant myocarditis usually has a rapid onset and causes more severe symptoms in a short period of time. This disease is commonly seen in adolescents and the main clinical symptoms are as follows: 1. Common myocarditis has a slow onset and may have prodromal symptoms of viral infection, which can be cured even without treatment. Some will have mild symptoms, such as post-activity panic or chest tightness. However, in fulminant myocarditis, severe symptoms can appear within a short period of time, and blood pressure can drop below 90/60 mmHg, mainly manifesting as wet and cold extremities and shock; 2. symptoms of pericarditis, such as coughing and chest pain, especially when the position changes, the chest pain symptoms will then worsen; 3. A-S syndrome, which refers to a decrease in heart beat volume due to rapid arrhythmias, eventually leading to cerebral ischemia seizures, convulsions, coma, and even sudden death. In summary, fulminant myocarditis has a high clinical mortality rate of more than 20% precisely because it develops very rapidly and can lead to severe symptoms.