Myocarditis is a common pediatric condition. Currently, there is a lack of highly sensitive and specific experimental diagnostic indicators for the diagnosis of pediatric myocarditis. In clinical work, there are some misunderstandings in the diagnosis and treatment of pediatric myocarditis, and parents are often confused “Is my child suffering from myocarditis?” 1, chest tightness, long breath is the performance of myocarditis? It is not uncommon for parents to bring their children to the clinic with the main complaint of “chest tightness and shortness of breath”. Chest tightness and shortness of breath can be a concomitant symptom of myocarditis. However, they are more often seen as “psychogenic (functional changes)”, and these children often have personality deviations, such as being cautious, sulking, aggressive, and introverted. 2, sinus tachycardia Whether the real sinus tachycardia, can not be diagnosed by a one-sided ECG, need to do 24-hour dynamic ECG examination comprehensive evaluation to clarify. Myocarditis can show sinus tachycardia. If sinus tachycardia alone is not accompanied by other abnormalities, attention should be paid to exclude hyperthyroidism, β-receptor hyperfunction, and inappropriate sinus tachycardia. 3.Can elevated cardiac enzymes alone diagnose myocarditis? CK-MB and troponin (CTnI, CTnT) abnormalities are one of the main indicators for the diagnosis of myocarditis, but should be considered in conjunction with clinical considerations. For example, the influence of age on the normal value of cardiac enzymes; excluding myopathy with a significant increase in CK or LDH; excluding liver function impairment and checking liver function only with an increase in AST; false positive cardiac enzymes due to hemolysis in the blood. 4. Premature beats (preterm contraction) Premature beats are the most common clinical arrhythmia in pediatrics. Most children are not found to have evidence of organic heart disease after comprehensive and systematic examination and are finally diagnosed as simple premature beats. The presence of premature beats should not be used as diagnostic evidence for myocarditis alone. 5. ST-T changes Some pediatric myocarditis ECGs may show changes in ST-T waves, sometimes even the only abnormal ECG manifestation. The diagnosis of myocarditis emphasizes ST-T wave changes lasting more than 4 days with dynamic changes. It should also be noted here that because of the obvious age-specific features of the pediatric ECG, the criteria for determining whether ST-T wave changes are pathologically significant cannot be fully followed in adults, such as T-wave changes in leads III, avL, and V3 can be normal in pediatric patients. Paroxysmal supraventricular tachycardia is more common in pediatric patients and is easily misdiagnosed as myocarditis. Paroxysmal supraventricular tachycardia is mostly due to congenital abnormalities of the cardiac conduction system, which can be identified by an ECG by experienced physicians. Some episodes of tachycardia are followed by changes in the ST-T wave of the electrocardiogram and abnormalities in cardiac enzymes, which cannot be used as a basis for the diagnosis of myocarditis.