In most cases, high creatine kinase isoenzymes in children are caused by symptoms of myocarditis. When a child is infected with a virus or bacteria, the pathogenic bacteria invade the myocardium and cause damage to the myocardial cells, which results in the release of creatine kinase isoenzymes from the myocardium into the bloodstream, causing an increase in creatine kinase isoenzyme concentrations. If a child has myocarditis, it can cause limitation of activity as well as panic, chest tightness, and pallor. If it is particularly severe, it can lead to heart failure and even death in children. If a child’s creatine kinase isoenzyme is significantly high, the child should be given an electrocardiogram in a timely manner and treated with myocardial nutrients.