Abstract
Arterial desaturation following surgical repair of tetralogy of Fallot (TOF) is rare. In most instances, it results from residual right ventricular outflow tract obstruction, causing right-to-left shunt across residual interatrial or interventricular communication. In this report, we present an unusual scenario of arterial desaturation due to a recanalized left cardinal vein in a child with repaired TOF. We also discuss stepwise evaluation that led to successful identification and occlusion of the abnormal venous channel by percutaneous device closure.