Pediatric myocarditis may present with symptoms such as malaise, palpitations, chest tightness, and severe symptoms of cardiac failure such as dyspnea and lower extremity edema. Myocarditis is mostly caused by viral infections, and symptoms of acute upper respiratory tract infection caused by viral infections such as fever, malaise, and muscle aches may occur before the onset of myocarditis. When the acute attack, often appear weakness, palpitations, arrhythmia, shortness of breath, chest tightness, chest pain and other symptoms, serious can cause dyspnea, lower limb edema, and even fainting and other acute left heart failure symptoms. When a child has symptoms of acute upper respiratory tract infection, followed by palpitations, shortness of breath and other symptoms, you need to consult a doctor in a timely manner, under the guidance of the doctor to clarify the cause and active treatment.