What are the causes of atrioventricular heart block?

The health of the heart has always been a concern for everyone. Heart disease can be divided into many types, some are congenital, some are acquired stones, and more serious than heart disease is atrioventricular conduction metabolism, which is an organ disease that affects the normal movement of the heart. It may be accompanied by a variety of cardiopulmonary failure. Many patients have this disease since birth and need timely surgery for treatment, otherwise their lives may be in danger. Some patients need to wear a pacemaker all year round to ensure a normal heart rate. Therefore, in the cause of the disease and the process of treatment, we must master the skills and have a comprehensive understanding.

1. Reasons

(1) Congenital type: simple conduction abnormalities (without structural heart disease), cardiac structural abnormalities such as congenital corrected transposition of the great vessels, or maternal diseases such as systemic lupus erythematosus, Sjogren's syndrome or other connective tissue diseases.

(2) Acquired type: The most common cause of complete atrioventricular block in children is cardiac surgery. Other rare causes include severe myocarditis, Lyme carditis, acute rheumatic fever, mumps, diphtheria, cardiomyopathy, conduction system tumors, drug overdose, and myocardial infarction. Conduction block may be temporary or permanent.

2. Prognosis

(1) Infants and young children may develop congestive heart failure, especially those with congenital heart defects.

(2) Patients with simple congenital conduction block usually have no symptoms after infancy and can grow and develop normally within the next 5-10 years. Chest X-rays may show an enlarged heart.

(3) When the ventricular rate is lower than 40-45 beats/minute, syncope (Aspergillian attack) may occur. Sudden acquired heart block can result in death if the heart rate is not maintained at an appropriate level.

3. Treatment

(1) Before temporary ventricular pacemaker implantation, atropine and isoproterenol can be used in children and adults with symptoms of conduction block.

(2) Transvenous temporary ventricular pacemaker is used to treat heart block or prevent the progression of heart block.

(3) Children with asymptomatic complete heart block if their heart rate is normal. No treatment is required if the QRS complex is not widened and ventricular function is normal.

(4) Indications for pacemaker implantation in patients with congenital atrioventricular block.

A. Symptomatic or developing congestive heart failure. Dizziness and lightheadedness are early warning signs of a pacemaker.

B. The infant's ventricular rate is less than 50-55 beats/minute; or the infant with congenital heart disease has a ventricular rate less than 70 beats/minute.

C. There is a wide QRS escape rhythm, complex ventricular ectopic rhythm or heart failure.

(5) Irreversible conduction block caused by cardiac surgery or conduction block persisting for at least 7 days after cardiac surgery is an indication for implantation of a permanent artificial pacemaker.

(6) Children may have different problems after having a pacemaker installed: excessive tension on the wires due to growth and development, wire breakage caused by strenuous exercise, battery malfunction (scarring of the myocardium around the battery, especially in infants), and limited lifespan of the pacemaker. All of these problems require follow-up of children with pacemakers.