instruction: how many hours it has been since patient 016-18575's last antiarrhythmics - class iv antiarrhythmic during the current hospital encounter?
response: SELECT 24 * (STRFTIME('%j', CURRENT_TIME()) - STRFTIME('%j', treatment.treatmenttime)) FROM treatment WHERE treatment.patientunitstayid IN (SELECT patient.patientunitstayid FROM patient WHERE patient.patienthealthsystemstayid IN (SELECT patient.patienthealthsystemstayid FROM patient WHERE patient.uniquepid = '016-18575' AND patient.hospitaldischargetime IS NULL)) AND treatment.treatmentname = 'antiarrhythmics - class iv antiarrhythmic' ORDER BY treatment.treatmenttime DESC LIMIT 1