Intrahepatic right-to-left shunting after the Fontan operation.

We describe two patients with right isomerism, corrected with a fenestrated Fontan operation, who suffered severe progressive cyanosis. Cardiac catheterisation in both revealed a massive right-to-left shunt from the inferior caval vein, through the liver, to a hepatic vein draining directly to the left side of the intra-atrial baffle. The anomalous vein was successfully ligated in both patients.