Unusual systemic venous Collateral channels to left atrium causing desaturation after Fontan operation closed percutaneously.

We present an unusual cause of progressive cyanosis in a child appearing 2 years after successful Fontan surgery for tetralogy of Fallot with hypoplastic right ventricle. The cause of cyanosis was identified as one large venous channel draining into the left atrium. The channel was closed by Amplatzer vascular plug resulting in improvement of oxygen saturation.