1. Causes (1) Congenital types: simple conduction abnormalities (without combined structural heart disease), structural heart abnormalities such as congenitally corrected transposition of great vessels, or maternal diseases such as systemic lupus erythematosus, Sjogren’s syndrome, or other connective tissue diseases. (2) Acquired types: The predominant etiology in children with complete AV block is cardiac surgery. Other rare causes include severe myocarditis, Lyme heart disease, acute rheumatic fever, mumps, diphtheria, cardiomyopathy, tumors of the conduction system, drug overdose, and myocardial infarction. Conduction block can be temporary or permanent. 2. Prognosis (1) Congestive heart failure may occur in infants and children, especially in those with combined congenital heart defects. (2) Simple congenital conduction block is often asymptomatic after living through infancy, followed by normal growth and development in the next 5-10 years, and X-ray chest radiographs may show an enlarged heart. (3) Syncopal episodes (As episodes) may occur when the ventricular rate is below 40-45 beats/min. Sudden onset of acquired heart block can lead to death if the heart rate cannot be maintained at an appropriate level. 3. Treatment (1) Atropine and isoprenaline may be used in children and adults with symptomatic conduction block prior to temporary ventricular pacemaker installation. (2) Transvenous installation of a temporary ventricular pacemaker is used for the treatment of heart block or to prevent the progression of conduction block. (3) In children with asymptomatic complete block, treatment is not necessary if the heart rate is normal, QRS waves are not widened, and ventricular function is normal. (4) Indications for pacemaker installation in congenital atrioventricular block. (1) Symptomatic or occurrence of congestive heart failure. Dizziness and blurred vision are early warning signs for pacemaker installation. ②Infants with a ventricular rate of less than 50-55 beats/min; or infants with congenital heart disease with a ventricular rate of less than 70 beats/min. (3) The presence of a wide QRS escape rhythm, complex ventricular ectopic rhythm, or cardiac insufficiency. (5) Irreversible conduction block due to cardiac surgery or conduction block lasting at least 7 days after cardiac surgery is an indication for the installation of a permanent artificial pacemaker. (6) Different problems can arise after pacemaker installation in children: excessive lead tension due to growth and development in children, lead breakage due to strenuous exercise, malfunction of the battery (scarring of the myocardium around the battery, especially in infants), and limited life span of the pacemaker all require follow-up of children with pacemakers.