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 autoantibody 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 >0.08s, 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 bad 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.