Prolongation of QT is very rare with these drugs - particularly hydroxychloroquine.
The whole QT prolongation fad is a thing with these newer Doctors coming on line in the last 15 years or so. Especially when psycho active drugs are needed for quieting of patients going thru transient psychosis and anxiety who may be a danger to themselves. If there is an off chance that someone might have a marginal enlarged QT....nope can’t the antipsychotic, tie them up and let them scream it out...even though in 34 years of nursing practice I’ve never seen r on t induced Vtach triggered by these drugs(which is what an over enlarged QT can trigger)...but in the last 10 years ago this QT business has become quite the rage amongst doctors of a certain age range. Sure it could happen...but so can meteor thru your roof. You give the drug as needed and monitor the patients and if over time they tolerate the drug...all to the good!