Clinical significance of maternal anti-Ro/SS-A antibodies in children with isolated heart block.

Objectives: We studied 30 consecutive children with isolated heart block to assess the clinical impact of the presence of maternal anti-Ro/SS-A antibodies for isolated heart block.

Background: Isolated heart block in children, often associated with maternal autoimmune disease leading to anti-Ro/SS-A auto-antibody production, is an infrequent but potentially lethal disorder.

Methods: Thirty children with isolated heart block were studied with respect to medical history and electrocardiographic (ECG) analysis. The presence of anti-Ro/SS-A antibodies was determined in the maternal serum. We also examined the ECGs of all brothers and sisters of the patients for conduction abnormalities.

Results: Twenty-one of the 30 children had an anti-Ro/SS-A-positive mother (group A); the other 9 children had an anti-Ro/SS-A-negative mother (group B). Comparison of the clinical data from both mothers and children revealed that these two groups differed significantly with respect to the following: Prenatal diagnosis and obstetric complications occurred more often in group A, whereas progression to complete block, QRS width > 0.08 s, premature ventricular contractions and ventricular standstills > 4.5 s occurred more often in group B. In addition, mothers of children in group A reported more spontaneous abortions. All siblings of children in groups A and B had normal ECGs, excluding a subclinical form of heart block.

Conclusions: Two types of heart block can be recognized: Congenital heart block is associated with maternal anti-Ro/SS-A antibodies and numerous obstetric and neonatal complications. It is diagnosed prenatally or at birth and is usually complete at onset and probably has a substantial recurrence risk. Heart block that is acquired later in life is not associated with maternal autoimmunity and has no risk for recurrence. It often presents as a partial block but progresses to complete block in time.