Summary: | With an incidence of 1 in 20000 live born infants1, congenital complete atrioventricular block (CCAVB) is a rare disease. The aetiology is not completely understood. However, CCAVB may be isolated or combined with congenital heart diseases in up to 53% of affected individuals2. Isolated CCAVB is in up to 98% of the children associated with positive autoimmune antibodies in the maternal serum (anti-Ro/SS-A and anti-LA/SS-B)3,4. Interestingly, these antibodies are not specifically directed against the conduction system but also against normal myocardial cells and may cause myocarditis5,6. Affection of the conduction system can occur at different levels7. Histologically, the atrioventricular node tissue may be replaced by fibrous fatty tissue with variable involvement of the distal conduction system8.
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