As the incidence of rheumatic myocarditis has decreased, the incidence of viral myocarditis has increased year after year in recent years, thus making the latter important. Viral myocarditis can occur at all ages and even invades newborns. As the incidence of rheumatic myocarditis has decreased, the incidence of viral myocarditis has increased year by year in recent years, so the importance of the latter cannot be overstated. Viral myocarditis can occur at all ages and even infest newborns. However, it prefers young people, including some children and adolescents, but is more common in patients aged 20 to 30 years, and 75% to 80% in those under 40 years of age. Generally speaking, myocarditis in infancy and early childhood has a rapid onset and is severe; myocarditis in adolescents mostly heals after treatment, and some patients are left with dilated cardiomyopathy or arrhythmias such as premature ventricular beats. Viral myocarditis is an inflammatory lesion of the myocardium caused by viral infection. On the one hand, the virus causes direct damage to the myocardium; on the other hand, the immune response of the myocardial immune system to the virus, including antibodies produced by the myocardium in the process of resisting the virus, also damages the myocardium. The clinical symptoms of viral myocarditis can be mild or severe, and the milder ones can be asymptomatic; the more severe ones can develop heart failure, arrhythmia, and even sudden death. The symptoms of myocarditis appear in 1 to 3 weeks. It can be divided into 6 types: 1. asymptomatic type: ST-T changes on ECG without any clinical symptoms; 2. arrhythmia type: various arrhythmias can occur, the most common being premature ventricular beats; 3. heart failure type; 4. myocardial necrosis type: cool myocardial infarction; 5. enlarged heart type; 6. sudden death type; 7. fulminant type: sudden shock, heart failure and severe arrhythmia within a few hours of onset. Depending on the course of the disease and its manifestations, it can be divided into acute phase (within 6 months), recovery phase (6-12 months), chronic phase (more than 1 year), and sequelae phase (asymptomatic, with residual ventricular premature, atrioventricular or bundle branch block. (arrhythmias such as atrioventricular junctional rhythm). The ECG of each period of viral myocarditis has different characteristics, and we can diagnose what period of viral myocarditis we are in at this stage by the different manifestations of the ECG, so that we can better treat with medication. The ECG changes in the acute and chronic phases of viral myocarditis are often diverse, variable and volatile, while the recovery and post-acute phases are less variable and less severe. The regression is characterized by the disappearance of about 1/2-4/5 of the pre-term contractions, disappearance of about 1/2-2/3 of the atrioventricular block, and 90-100% recovery of ST I-T changes. Prolonged non-recovery of the ECG can be a form of presence of myocarditis in the chronic phase or in the posterior phase. The ECG changes in the chronic phase of myocarditis are similar to those in the acute phase, except that they are characterized by more hypertrophy of each atrium, accounting for 44.7%, whereas in the acute its no left ventricular hypertrophy is seen, indicating that ventricular hypertrophy is an important manifestation of the chronic phase. The ECG changes in the posterior phase of myocarditis are less varied, less severe and relatively stable. There are usually only 1-2 changes. The main one is anterior contraction, but there are neither symptoms nor functional changes, and treatment is often ineffective. Secondly, there may be first degree AV block or incomplete right bundle branch block.