Staying up late has no effect on the ECG, and if the ECG changes after staying up late, it shows myocardial ischemia as well as the appearance of arrhythmia. Patients with myocardial ischemia often have chest tightness and chest pain after activity. At this time, if an ECG is done, half of them may find partial ST-T segment changes in the ECG, including horizontal or downward sloping depression of ST segment, or low and flat T wave or even inversion. When the chest pain is relieved and disappears, the ECG will be done again and the above changes will return to normal waveform. Therefore, the appearance of the above-mentioned manifestations after staying up late indicates that staying up late causes the patient to show angina pectoris. If recurrent panic occurs after staying up late, and the ECG reveals frequent premature beats or even atrial fibrillation and supraventricular tachycardia, it is considered that staying up late as a trigger causes arrhythmia. However, at this time, staying up late is only a trigger but not a cause. Patients often have underlying structural heart disease and need to be hospitalized for electrophysiological surgery and radiofrequency ablation before they can be cured. Therefore, staying up late does not affect the ECG, but if it does, it is often because the patient has underlying heart disease, including coronary system disease and arrhythmias.