when was the last time patient 14502 was measured heart rate less than 83.0 on 04/02/2103?
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 = 14502 ) ) 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 < 83.0 and strftime('%y-%m-%d',chartevents.charttime) = '2103-04-02' order by chartevents.charttime desc limit 1