A boy with fatigue and heart block: what's the mechanism?

When the atrioventricular node is damaged, accessory pathways can perform primary atrioventricular conduction but may spontaneously degrade during childhood. After surgical atrial septal defect repair during infancy, an adolescent male presented with fatigue due to iatrogenic complete atrioventricular node block with a degrading antegrade accessory pathway resulting in symptomatic bradyarrhythmia.

Late recovery of sinus rhythm following perioperative complete atrioventricular block in a child with congenitally corrected transposition.

We report a patient with l-transposition of the great arteries who developed perioperative complete atrioventricular block at 5 years of age in conjunction with a modified double-switch operation, but had unexpected late recovery of normal sinus rhythm months later. This case highlights that even for patients with l-transposition, which is particularly vulnerable to developing both spontaneous and perioperative complete atrioventricular block, late recovery of atrioventricular node conduction may still be possible after surgery.