BA 170 then BA 594 at Heathrow
Pittsburgh → London → Venezia
Timetable, London time
09:40BA 170 from Pittsburgh at the gate
08:05BA 594 to Venezia leaves the gate
22 h 25 apart on the timetable, overnight
BA 594 leaves 22 h 25 after BA 170 arrives on the timetable: more than half a day, so not a connection we count.