Circadian Rhythm and ST

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 prehospital 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 prehospital delays of 150 minutes versus 90 minutes from 6:00 to 11:59 and 12:00 to 17:59, respectively (P < .001). Although there was no significant difference in mortality between the 4 groups (P = .230), there was a significant association between time of symptom onset as sinusoidal function and in-hospital mortality (P = .032). Patients with STEMI in the Middle East have significant circadian patterns in symptoms onset, prehospital delay, and timeliness of reperfusion. A circadian rhythm of in-hospital mortality was found over the 24-hour clock of symptom onset time