Alsheikh-Ali, Alawi2021-08-032021-08-032019-04204-2019.46https://repository.mbru.ac.ae/handle/1/342Abstract: Circadian rhythms have been identified in multiple physiological processes that may affect cardiovascular diseases, yet little is known about the impact of circadian rhythm on acute ST-segment elevation myocardial infarction (STEMI) onset and outcomes in the Middle East. The relationship between time of symptom onset during the 24-hour circadian cycle and pre-hospital delays and in-hospital death was assessed in 2909 patients with STEMI presenting in 6 Arabian Gulf countries. A sinusoidal smoothing function was used to show the average circadian trends. There was a significant association between time of symptom onset and the circadian cycle. The STEMIs were more frequent during the late morning and early afternoon hours (P< .001). Patients with pain onset from 0.00 to 5:59 had median pre-hospital delays of 150 minutes versus 90 minutes from 6:00 to 11:59 and 12:00 to17:59, respectively (P< .001). Although there was no significant difference in mortality between the 4 groups (P¼.230), there was a significant association between time of symptom onset as sinusoidal function and in-hospital mortality (P¼.032). Patients with STEMI in the Middle East have significant circadian patterns in symptoms onset, pre-hospital delay, and timeliness of reperfusion. Acircadian rhythm of in-hospital mortality was found over the 24-hour clock of symptom onset time.enMyocardial infarctionCircadian rhythmArabian GulfReperfusionArticle