1, test methods: test requirements should be in a quiet room, dim light, the temperature is appropriate, before the experiment should let the child lie down for 20 minutes. To prepare the first aid drugs and CPR equipment. The child should be fasted for at least 3 hours, discontinued from vasoactive drugs for at least 5 half-lives, and have equipment for simultaneous monitoring of heart rate and blood pressure. The child is allowed to stand on an inclined bed with a certain tilt angle (mostly 60°~70°), and the changes in blood pressure and heart rate are recorded every 1-2 minutes, while the child is asked about the symptoms until a positive response occurs or the full 45-minute procedure is completed. 2. Test results: (1) vasovagal syncope: the child is considered positive if one of the following conditions is present: (2) syncope aura with blood pressure drop or/and heart rate slowdown; (3) syncope aura with sinus arrest, junctional escape heart rate, transient second-degree or higher atrioventricular block and sinus arrest of up to 3 seconds. The criteria for blood pressure drop were systolic blood pressure ≤ 80 mmHg (systolic blood pressure drop > 20 mmHg) or diastolic blood pressure ≤ 50 mmHg or mean blood pressure drop ≥ 25%. If the child does not meet the above criteria, but has developed syncope or syncope aura, it is still positive. Heart rate slowing is defined as bradycardia: 7-8 years old, heart rate <65 beats/min; 8-15 years old, heart rate <60 beats/min, ≥16 years old, heart rate <50 beats/min. The response can be divided into 3 types: ① Cardiac suppression type: characterized by a decrease in heart rate, presenting bradycardia and elevated or mildly decreased systolic blood pressure. ②Vascular depression type: blood pressure decreases significantly, accompanied by increased or mildly slowed heart rate. (3) Mixed type: Both blood pressure and heart rate are significantly decreased. (2) Postural tachycardia syndrome:: During the upright tilt test, the patient's heart rate increases by 30 beats/min or the heart rate increases by more than 120 beats/min within 10 minutes compared to the prone position, which is called postural tachycardia syndrome. (3) Upright hypotension: A sustained drop in blood pressure of more than 20 mmHg systolic or 10 mmHg diastolic within 3 minutes of the upright tilt test is called upright hypotension.