Coexistence of atrioventricular block and Wolff-Parkinson-White syndrome in children

Coexistence of atrioventricular block and Wolff-Parkinson-White syndrome is uncommon, but may occur in children, particularly with certain congenital heart defects. Our study describes 5 children who had pre-excitation and underlying disturbance of atrioventricular conduction All of these patients had structural heart defects, consisting of discordant atrioventricular connections in three, double inlet left ventricle in one, and a ventricular septal defect associated with straddling of the tricuspid valve in the other. In 4 of the patients, the presence of atrioventricular block was initially masked by the pre-excitation. When the conduction through an accessory pathway is lost, the child may be left with atrioventricular block, which is poorly tolerated in the setting of complex cardiac anatomy. Awareness of this association of Wolff-Parkinson-White syndrome and atrioventricular block is important in understanding the natural history and the management of children with congenital heart defects that are associated with tenuous atrioventricular conduction.