Acute myocarditis in children refers to inflammation of the heart muscle that occurs suddenly and typically lasts for a short period of time. This type of myocarditis can cause symptoms such as chest pain, shortness of breath, and abnormal heart rhythms. In some cases, acute myocarditis may resolve on its own, while in other cases, medical treatment may be required. The diagnosis of acute myocarditis in children is based on a combination of clinical presentation, medical history, and test results.