Symptoms of myocarditis in two-year-old babies mainly include respiratory and gastrointestinal symptoms, and some babies may even be diagnosed without obvious clinical symptoms and only have elevated cardiac enzyme levels. 1. Some babies may have no obvious clinical symptoms, and are diagnosed with myocarditis only because of arrhythmia and elevated cardiac enzymes found during physical examination. 2. Some babies may have symptoms such as fatigue, limitation of activity, palpitations, chest pain, etc. In a few severe cases, heart failure with severe arrhythmia and cardiogenic shock may occur. There is mild enlargement of the heart with tachycardia, muffled heart sounds and gallop rhythm. In repeated heart failure, there is marked enlargement of the heart, wet rales in the lungs and liver and spleen enlargement, shortness of breath and cyanosis. When suspecting the possibility of myocarditis in babies, they should go to regular hospitals in time and be treated under the guidance of doctors so as not to delay the condition.