ครั้งสุดท้ายที่ผู้ป่วย 19473 มีอัตราการเต้นของหัวใจต่ำกว่า 66.0 คือเมื่อใด ไม่จำเป็นต้องใช้ตารางทั้งหมด
when was the last time that patient 19473 had a heart rate that was less than 66.0?It is not neccessary to use all the tables.
 admissions:  row_id [ number]  subject_id [ number]  hadm_id [ number]  admittime [ time]  dischtime [ time]  admission_type [ text]  admission_location [ text]  discharge_location [ text]  insurance [ text]  language [ text]  marital_status [ text]  ethnicity [ text]  age [ number] 
SELECT chartevents.charttime FROM chartevents WHERE chartevents.icustay_id IN (SELECT icustays.icustay_id FROM icustays WHERE icustays.hadm_id IN (SELECT admissions.hadm_id FROM admissions WHERE admissions.subject_id = 19473)) AND chartevents.itemid IN (SELECT d_items.itemid FROM d_items WHERE d_items.label = 'heart rate' AND d_items.linksto = 'chartevents') AND chartevents.valuenum < 66.0 ORDER BY chartevents.charttime DESC LIMIT 1