The treatment of third-degree AV block is mainly directed at the cause of the disease, such as hypoxia and acidosis can also occur in third-degree AV block. Timely correction of hypoxia and acidosis can improve myocardial conduction function, which can lead to improvement of third degree AV block. In case of temporary injury due to myocarditis or surgery, adrenocorticotropic hormone, elimination of local edema, oral atropine, ephedrine or sublingual isoprenaline may be used to improve the clinical manifestations of third-degree AV block. In severe cases, atropine subcutaneously or intravenously or isoproterenol 1 mg dissolved in 5%-10% glucose injection 250 ml and continuously administered intravenously at a rate of 0.05-2 μg/(kg.d) should be applied. Then the intravenous drip is administered, ECG monitoring is performed, and the infusion rate is adjusted according to the ECG performance and heart rate, which usually improves the clinical manifestations of third-degree AV block and also allows third-degree AV block to proceed to disappear. However, there are some special cases, for example, when drug therapy is ineffective, only a pacemaker can be installed. The indications for installing a pacemaker are recurrent episodes of A.S. syndrome and ineffective drug therapy. A temporary pacemaker is usually installed for 4 weeks to see if the child’s atrioventricular block recovers, and if it does not recover in 4 weeks, a permanent pacemaker is installed. Permanent pacemakers have to be carried by the child for life and are troublesome to treat, and even the installed permanent pacemakers need to be replaced periodically.