My friend had an ekg done and his qt/qtc was 475/400. does this mean he has prolonged qt interval? he's on seroquel (quetiapine)

Lots of drugs do : The qtc interval is prolonged by multiple commonly used drugs, and seroquel (quetiapine) is but one. The duration is not severe, and likely appropriate at this point, but certainly on the high normal side. Maybe need to monitor, but typically these items do not cause symptoms unless too many drugs affect the a/v nodal conduction.