The clinical symptoms of pediatric myocarditis depend on the severity of the disease and the age of the child. In severe cases, heart failure, malignant arrhythmias, cardiogenic shock, and even death may occur. Some patients may also progress to dilated cardiomyopathy because they have not recovered well in the early stages. If a newborn has myocarditis, the symptoms are often severe and can include high fever, wheezing, dyspnea, cyanosis, and often liver and pulmonary and neurological complications. In children with myocarditis, tachycardia can be observed on physical examination, some patients may have low heart sounds and gallop rhythm, wet rales may be heard in the lungs, and in severe cases, a drop in blood pressure and a weak pulse may be observed. In addition to these abnormalities, some patients may also have a large liver and spleen. Children with myocarditis may have elevated creatine kinase isoenzymes and troponin. x-rays may show an enlarged heart shadow. Early in the course of the disease, the titer of specific IgM antibodies in the blood is above 1:128. Cardiac ultrasound may show enlargement of the atria and blood vessels, and in some patients, impaired ventricular systolic function. The gold standard test to confirm the diagnosis of myocarditis is a myocardial biopsy. In children, absolute bed rest is required during the acute phase of myocarditis so that the load on the heart can be reduced. In addition to adequate rest, drugs that nourish the heart muscle, such as fructose 1,6-diphosphate, can be used to help improve myocardial energy metabolism and repair damaged cells. High doses of immunoglobulins can also be used to reduce the damage to cardiac muscle cells through immunomodulation. Patients who develop arrhythmias and symptoms of heart failure during the course of the disease are treated mainly with symptomatic support.