Intra-Hisian Wenckebach after surgical closure of conoventricular ventricular septal defect.

We report a 5-year-old girl with transient complete atrioventricular (AV) block following surgical closure of a symptomatic conoventricular ventricular septal defect (VSD) which recovered on post-operative day 9. She later presented with exertional dizziness and fatigue. While congenital cardiac defect repairs are occasionally complicated by complete heart block, this patient was found to have intra-Hisian Wenckebach which is rare in the pediatric population and can be very difficult to discern from surface electrocardiograms and by Holter monitoring. Mechanisms of post-surgical AV block, including intra-Hisian Wenckebach, are not well characterized in the pediatric population.