The total heart rate in 24 hours is around 80,000-100,000 beats, if it is less than 80,000 beats, it is initially judged as sinus bradycardia, if it is more than 100,000 beats, it is sinus tachycardia. 3, to see if there is arrhythmia, it depends on the nature of the arrhythmia, such as atrial arrhythmia, ventricular arrhythmia, conduction block, sinus arrest. 4, to see if there is myocardial ischemia, if the ST segment is elevated or shifted downward, if the ST segment is shifted downward by 0.05mV, it can be judged as myocardial ischemia. If the ST segment is elevated or shifted downward, it can be judged as myocardial ischemia, and then the direction of T wave is upright or normal.