The electrocardiogram is a record of the electrical excitation of the heart, which relies on the conduction system inherent in the heart’s anatomy and physiology. Each time the heart beats, the ECG records a complete cardiac cycle waveform. Ventricular systole is completed by ventricular diastole producing a T wave. Therefore, a variety of causes affecting ventricular diastolic function may cause changes in the T wave. T-wave inversions seen clinically are not always a manifestation of cardiovascular abnormalities, but can also be caused by many non-cardiovascular causes. 1. Myocardial ischemia: This is, of course, the cause that most people can think of. It is usually believed that at least one larger coronary artery with luminal stenosis of more than 50% will trigger symptoms of transient myocardial ischemia (oxygen) when myocardial oxygen consumption increases to a certain level with overexertion. The ischemic electrocardiogram may have S-T segment reduction and T-wave inversion at the time of ischemia tracing, but the ischemic S-T segment and T-wave changes disappear with the relief of ischemic symptoms. There is no protracted T-wave inversion in the quiet state. Unless myocardial infarction has occurred, T-wave inversion may remain for several months or longer after the acute phase. 2, ventricular hypertrophy: long-term hypertension, hypertrophic cardiomyopathy, congenital heart malformations, and various causes of heart valve disease can cause ventricular hypertrophy and dilation. The T-wave inversions caused by the above-mentioned causes are more persistent and do not change much, and as the degree of ventricular hypertrophy increases, the T-wave inversions may also gradually become deeper. 3, myocarditis: various causes of myocarditis after recovery may remain persistent T-wave flat, bi-directional or inverted. 4, pericardial disorders: various causes of pericarditis or pericardial effusion can appear T-wave flat or inverted. 5, arrhythmia: such as complete bundle branch conduction block or non-sinus conduction ectopic rhythm can appear T wave changes, paroxysmal tachycardia or atrial fibrillation can appear after the conversion of electro-tension adjustment of T wave inversion. 6.After cardiac surgery: T-wave inversion can be seen in the pacing rhythm after ventricular pacemaker implantation and the electrocardiogram after coronary artery bypass grafting. 7.Electrolyte disorders in the body: severe vomiting and diarrhea caused by digestive system diseases, chronic wasting diseases leading to hyperemesis, excessive fluid loss due to diuresis, hypokalemia and hypocalcemia can cause T-wave flattening or inversion. 8, drugs: such as digitalis, anti-arrhythmic drugs can also lead to T-wave inversion. 9, other diseases: hypothyroidism, pulmonary embolism or chronic lung disease, intracranial hemorrhage, etc. can be seen in the T wave flat, bidirectional or inverted.