Circadian variation in ST-segment elevation myocardial infarction: a nationwide analysis of onset, treatment delays, and culprit artery patterns

Circadian variation in ST-segment elevation myocardial infarction: a nationwide analysis of onset, treatmentdelays, and culprit artery patterns Pol Arch Intern Med. 2026 Jan 7:17188. doi: 10.20452/pamw.17188 Abstract Introduction: ST-segment elevation myocardialinfarction (STEMI) onset follows a circadian rhythm, yet data from large contemporary national registries remain limited, particularly regarding how onset time influences treatment delays and coronary pathology. Objectives: To examine circadian patterns of ST-segmentelevation myocardial infarction onset and their impact on treatment delays, culprit vessel involvement, and periprocedural mortality. Patients and methods: We retrospectively analyzed 1,53,543ST-segment elevation myocardial infarction patients from the Polish National PCI Registry (ORPKI) between 2014 and 2022. We examined the hourly distribution of symptom onset and its associations with patient characteristics, treatmentdelays, and infarct-related artery location. Results: ST-segment elevation myocardial infarctiononset showed pronounced circadian variation, peaking at 8:00 AM. Although the overall pattern was similar between sexes (P for interaction = 0.15), median onset timeoccurred significantly earlier in males than females (10:00 AM vs. 11:00 AM, P = 0.007). Nocturnal onset (e.g., 3:00 AM) was associated with substantially longer median pain-to-first-medical-contact times compared with daytime onset (180 vs. 90 minutes at 1:00 PM; P <0.001). We identified a novel opposing circadian rhythm for the infarct-related artery location: left anterior descending (LAD) artery identified as the infarct-related artery peaked during nocturnal hours with a nadir at noon, while right coronary artery (RCA) involvement demonstrated the inverse pattern (P <0.001). Despite delayed presentation, periprocedural mortality did not vary significantly by onset time. Conclusions: This large nationwide cohort demonstrates that ST-segment elevation myocardial infarction onset follows arobust circadian pattern significantly affecting system delays. The discovery of opposing circadian rhythms for left anterior descending versus right coronary artery involvement suggests that time of day influences not only ST-segmentelevation myocardial infarction triggering but also its pathophysiological manifestation. Disclaimer: Lupin makes no representation or warranty of any kind, expressed or implied, regarding the accuracy, adequacy, validity, reliability, availability, or completeness of any scientific information shared by the HCP on the ­­­STARUPDATE podcast. You should not allow the contents of this to substitute for your own medical judgment, which you should exercise in evaluating the information on this website.