Whether ST depression 0.15 is serious or not is related to the cause of the disease, if it is physiological, it is not serious, if it is caused by pathology, it is serious. 1. Physiological factors: ST segment is normally an isoelectric line, sometimes there will be a slight shift, this is a normal physiological phenomenon, not caused by pathological factors, this can be assessed by the doctor, to exclude the impact of disease, this situation does not require special attention. Patients can relax their mind, no need to be overly nervous, normal life and work. 2. Pathological factors: ST-segment depression is common in myocardial ischemia, non-ST-segment elevation myocardial infarction, ventricular hypertrophy and sinus tachycardia, etc. T-wave flattening and inversion may indicate myocardial infarction, which is more serious. At this time, it is necessary to combine the patient’s symptoms and signs, such as tachycardia, chest pain, etc. and other tests, such as cardiac ultrasound, cardiovascular angiography, to clarify the condition. Serious examination is needed to avoid delaying the condition. It is recommended to consult a doctor in time if the cause of ST-segment changes is not clear, so as to discover the condition in time to avoid delaying the condition.