How can a baby acquire AV block?

A baby may acquire atrioventricular (AV) block as a result of maternal systemic lupus erythematosus (SLE) due to the presence of specific autoantibodies, particularly anti-Ro/SSA and anti-La/SSB antibodies. These antibodies can cross the placenta and affect the fetal heart, leading to congenital heart block. The mechanism involves inflammation and damage to the conduction system of the heart, which is responsible for maintaining the heart’s electrical rhythm. This can lead to varying degrees of AV block, commonly resulting in complete heart block, which is particularly concerning and may require early intervention after birth.

Maternal diabetes, hypertension, and drug use do not have a well-established direct link to the mechanism by which congenital AV block occurs. While these conditions can lead to a variety of complications in pregnancy, they are not specifically associated with the autoimmune process that causes fetal heart block as seen with maternal SLE.