Circadian rhythmicity in patients with out-of-hospital cardiac arrest and ST-segment elevation myocardial infarction: A scoping review

Abstract

Introduction: Out-of-hospital cardiac arrest (OHCA) and ST-segment elevation myocardial infarction (STEMI) are time-critical events that exhibit circadian patterns, which influence their incidence and clinical outcomes.

Objective: To determine whether circadian rhythmicity influences the time of onset of OHCA and STEMI, as well as related clinical outcomes, in patients requiring prehospital emergency care and subsequent hospitalization.

Design: A scoping review.

Methods: The search process included four online databases: MEDLINE Complete, CINAHL Plus with Full Text, ScienceDirect, and ProQuest. The review included original articles published between January 2010 and December 2024.

Results: Eighteen studies met the inclusion criteria. These revealed that the incidence of OHCA and STEMI exhibits significant circadian variability, with the highest incidence in the morning. OHCA often has a secondary afternoon/evening peak. The nighttime hours are associated with the lowest incidence. Patients with nighttime OHCA or STEMI have a lower probability of return of spontaneous circulation and worse one-month and one-year survival and neurological outcomes. This less favorable prognosis is not due to the time of day when the event occurs but rather due to limited bystander availability, lower rates of bystander cardiopulmonary resuscitation and defibrillation, and longer times to hospital intervention. Additionally, these events were more frequently recorded in winter, while weekly variations were insignificant.

Conclusion: Circadian and seasonal factors influence the occurrence and clinical course of OHCA and STEMI, with worse outcomes for nighttime cases being more a consequence of limited availability than the time of the event itself.