Late complete heart block post-tetralogy of Fallot repair: a possible new predicting, precipitating factor and review of related cases.

Tetralogy of Fallot (TOF) is the most common form of cyanotic congenital heart disease beyond the age of 3 months. Complete heart block (CHB) is rare but a serious sequalae post-repair of TOF. We present a case of an 18-month-old child who developed late CHB after around 1 year of the corrective surgery of the congenital anomaly. On the regular follow-up visit, the patient assessment was unremarkable. However, there was bradycardia, 55 beats/min. The ECG showed complete atrioventricular dissociation. Echocardiogram was done and demonstrated severe tricuspid regurgitation (TR). The patient required a permanent pacemaker and he is currently well. We are presenting this case as a late unexpected CHB, with a possibility of progressive right-side dilatation as a contributing factor to CHB due to severe TR.