Serum myoglobin is a type of cardiac enzyme that can be used for early assessment of whether a patient is experiencing acute myocarditis or myocardial infarction, and the first 2 hours of an infarction can help predict it. However, myocardial enzymology is less specific, and it can be elevated by many diseases, such as fractures, myocardial injury, rhabdomyolysis, colds, severe infections, and some tumors, in addition to heart attacks and myocarditis. Therefore, the elevation does not necessarily mean that the patient has myocardial injury, but further ECG examination and the patient’s current clinical symptoms should be asked. In some patients without heart disease, serum myoglobin may be significantly elevated after strenuous exercise if the muscles of the lower limbs are painful, while other indicators of cardiac enzymology are normal.