If the patient’s current ECG indicates sinus rhythm with ST-segment changes in some leads, this often means that the patient may have myocardial ischemia, or ST-segment changes due to pericardial effusion or premature repolarization syndrome. Other patients may have an acute myocardial infarction and may have an ST-segment elevation or horizontal ST-segment shift, which cannot be ruled out as a result of a non-ST-segment elevation myocardial infarction. If you want to further clarify what kind of abnormal changes are caused by this problem, you should also check cardiac enzymes and cardiac ultrasound, and if necessary, coronary angiography. Electrocardiogram can only represent the possibility of myocardial ischemia, and some patients have non-specific ST-segment changes in some leads, which often have no clinical significance.