Children with Tetralogy of Fallot may develop acute severe cyanosis or hypoxic<unk> ".  The<unk>  are unpredictable and are associated with profound cyanosis and can be fatal.
Tet spells
Kussmaul breathing
Sleepwalking
Tetany
Constipation  in kids
Snakebites
Snakebites 
Trench mouth