Influence of circadian, seasonal and climatic variables in ST-elevation myocardial infarction onset and outcomes.

Abstract

Background: ST-elevation myocardial infarction (STEMI) onset has been demonstrated to follow a circadian pattern, with peak incidence in the early hours of the day. Few studies have investigated climatic factors. This study aimed to assess whether circadian, seasonal and climatic factors influence the onset of STEMI and outcomes in an Australian cohort.

Methods: Symptom onset time was recorded in 5,865 patients who underwent percutaneous coronary intervention (PCI) for STEMI between 2005 and 2016. Data were from the Melbourne Interventional Group registry and analysed according to season, month, weekday, and linked climatic variables obtained from the Bureau of Meteorology and Environment Protection Authority. Multivariate analysis was performed to determine predictors of 30-day major adverse cardiac events (MACE) and National Death Index (NDI)-linked mortality.

Results: The STEMI onset occurred more frequently between 07:00 and 17:59 hours (mean time: 1148 ± 6.12 hours), with no significant difference seen between season, month or weekday. The STEMI onset was associated with differences in temperature (p < 0.001), humidity (p < 0.001), mean atmospheric pressure over the preceding 24 hours (p < 0.05), variance of temperature over the preceding 24 hours (p < 0.05), and particulate matter of < 10 μm (p < 0.001). Lower atmospheric pressure at the time of STEMI onset was an independent predictor of 30-day MACE (HR 1.10, 95% CI 1.01–1.20, p = 0.024). Climatic factors did not predict NDI mortality with a mean ± SD follow-up of 5.08 ± 3.5 years.

Conclusion: In this cohort, STEMI symptom onset was more frequent within daylight hours. Climatic variables appeared to play a role in timing onset of STEMI.