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 practice, there are some misconceptions about the diagnosis and treatment of pediatric myocarditis, and parents are often confused about “Is my child suffering from myocarditis?” 1. Is chest tightness and breathlessness a sign of myocarditis? It is not uncommon for parents to bring their children to the clinic with complaints 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. The diagnosis of sinus tachycardia cannot be made unilaterally by a single ECG, but by a comprehensive evaluation of 24-hour ambulatory ECG. Myocarditis can manifest sinus tachycardia. In case of simple sinus tachycardia without other abnormalities, hyperthyroidism, β-receptor hyperfunction, and inappropriate sinus tachycardia should be excluded. 3. Can myocarditis be diagnosed with elevated cardiac enzymes alone? Abnormalities in cardiac isoenzymes (CK-MB) and troponin (CTnI, CTnT) are one of the main indicators for the diagnosis of myocarditis, but should be considered in the context of clinical considerations. For example, the effect of age on the normal value of cardiac enzymes; CK or LDH is significantly increased, except for myopathy; only AST is increased, except for liver function damage, check the liver function; take the blood is not smooth hemolysis makes cardiac enzymes false positive, etc. Premature beats are the most common clinical arrhythmia in pediatrics. Most children are diagnosed with simple premature beats after comprehensive and systematic examination without evidence of organic heart disease. The presence of premature beats alone should not be used as diagnostic evidence for myocarditis. 5. ST-T changes Some pediatric myocarditis ECGs may show changes in ST-T waves, sometimes even as 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, e.g., 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 most often due to congenital abnormalities of the cardiac conduction system, which can be identified by an electrocardiogram 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.