Atropine test is mainly used to determine the disease of sick sinus node syndrome in clinical practice. Generally, a negative atropine test can exclude sick sinus node syndrome, while a positive atropine test can determine sick sinus node syndrome. The atropine test is based on the fact that atropine relieves the vagus nerve from inhibiting the heart, and that injecting a certain amount of atropine into the body will cause the heart rate to increase. However, in patients with sick sinus node syndrome, even if a certain dose of atropine is injected, the heart rate does not increase, and often the heart rate is less than 90 beats per minute, and some patients have junctional rhythm or bradycardia. If the above three conditions occur, it is considered a positive atropine test and can be identified as pathological sinus node syndrome, otherwise it is considered a negative atropine test and can be excluded as having pathological sinus node syndrome.