Sinus rhythm ST-segment elevation means that the patient may have angina pectoris or myocardial infarction. The so-called sinus rhythm is actually the normal heart rate, because the human heart conduction originates from the sinus node, so in medical terms it is called sinus rhythm. ST-segment elevation is a typical manifestation of myocardial ischemia, and if there are two or more leads of ST-segment elevation on the ECG, caution must be exercised because the patient is likely to be in the acute phase of myocardial infarction or acute pericarditis. In this case, it is necessary to combine the patient’s clinical symptoms and also to test the cardiac enzymes. If the cardiac enzymes are elevated at the same time, it is necessary to hospitalize the patient.