The laboratory test for cardiac enzymes is very commonly used in cardiovascular medicine, and this test is helpful in assessing whether the patient currently has myocarditis or if there is an acute myocardial infarction. If a patient is taking statin lipid-lowering drugs for a long time and is found to have symptoms of lower limb weakness and myalgia, cardiac enzymes are routinely examined to help assess the possibility of myocarditis or rhabdomyolysis. In addition, in patients with hypothyroidism, myocardial enzymes may be abnormal. If myocarditis or acute myocardial infarction is highly probable, further tests for creatine kinase isoenzyme, troponin I, and troponin T are recommended, as these enzymes are relatively more specific. However, for a definitive diagnosis, ECG and, if necessary, coronary angiography should be performed.