Second degree atrioventricular block is divided into second degree I and second degree II. Second degree I is not serious if it occurs occasionally at night and there are no symptoms related to bradycardia such as long cardiac arrest, dizziness, blackness in front of the eyes or fainting. Type II is more serious, but we need to evaluate the condition based on the absence of bradycardia-related symptoms such as long cardiac arrest, dizziness and blackness, or fainting, and if necessary, a pacemaker can be installed. In the case of second degree AV block in young people or adolescents, it is easy not to install a pacemaker because it is possible to recover from second degree AV block in adolescents, such as poor nutritional status or recent emotional anxiety or poor sleep, which can cause second degree AV block, and such block can return to normal after removing the cause. Severe infection, severe anemia, or myocarditis can also manifest as second-degree AV block, and if the myocarditis has recovered, second-degree AV block may also return to normal.