The Success of a New Protocol for Early Diagnosis and Management of Congenital Atrioventricular Block: A Follow-up Study of 15 Fetuses from November 2007 to August 2022

Congenital atrioventricular heart block (CAVB) is a relatively rare condition that can lead to long-term complications. Early diagnosis and management of CAVB is currently the ideal goal, particularly in high-risk pregnancies.

The Fetal Heart Center at Kurdistan University serves as the primary referral center for pregnant mothers residing in the western region of Iran. Fifteen fetuses with CAVB were admitted between November 2007 and August 2022. They were referred for one or more of the following reasons: fetal bradycardia or arrhythmia, abnormal ultrasound findings, and previous maternal or fetal risk factors. After obtaining a complete medical history, we conducted fetal echocardiography and ordered testing for maternal Lo/Ra autoantibodies. Our therapeutic approach was based on the type of atrioventricular block (AVB), serum titer of Lo/Ra antibodies, and specific risk factors associated with each type of AVB. Consequently, we used a combination of different medications, including dexamethasone, Hydroxychloroquine (HCQ), IVIG, beta-agonists, and inotropes.

We admitted 15 fetuses with CAVB, including seven females (47%) and eight males (53%). Most of our cases had positive tests for Lo and Ra autoantibodies, with varying degrees of AVB. A previous fetal death wascommon in our case series, accounting for 47% of cases. Moderate and high antibody titers were present in 80% of our cases. Mild bradycardia was a relatively common finding in our cases of first and second-degree atrioventricular block (AVB), occurring in 33% of patients. All of the above-mentioned findings, commonly referred to as major risk factors, were used for either early evaluation or therapeutic goals. No cases with first-degree AVB developed a higher grade of AVB after our therapeutic approach. One fetus with second-degree AVB developed CCHB, and another with mixed second/third-degree AVB reverted to second-degree AVB with the use of appropriate medications.

Our therapeutic approach for the current cases yielded satisfactory results. Subsequently, we attempted to develop a rudimentary approach for early managing and treating fetuses with various types of CAVB.We are looking forward to future multicenter studies.