Breath holding spell has a precipitating factor (does not occur abruptly) which causes the child to cry incessantly and this is followed by breath holding.
Classic Blalock Taussig shunt (BT shunt) is done on opposite side of aortic arch so that brachiocephalic trunk prevents kinking of the subclavian artery.
Catch 22 syndrome or 22q11 deletion is likely if there are dysmorphic features and arterial anomalies in TOF like right aortic arch and PA branch stenosis.