First degree AV block basically does not cause symptoms of dizziness and does not require long-term medication, and patients can run. Second degree AV block can be divided into second degree type I and second degree type II, which basically cannot be cured. Third degree AV block is very serious, and if symptoms occur, a permanent pacemaker needs to be placed, and its long-term survival rate is still quite high after the placement of the pacemaker. Third-degree AV block is characterized by a slow heart rate and a possible irregular rhythm on auscultation. The activity of the atria and ventricles in third-degree AV block are independent and unrelated to each other. The ventricular rate may be in the range of 40-60 beats per minute, or 40 beats per minute if the ectopic pacing is stopped in a lower position.