The four seasons in acute coronary syndrome

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Acute coronary syndrome (ACS) is one of the most common health problems in the world, and the leading cause of death. The goals of this study are to determine ACS incidence and the seasonal distribution of ocurrence (Spring/Summer/Autumn/Winter) as well as clinical outcomes per season. Methods Retrospective and observational analysis of consecutive patients hospitalized for ST-elevation myocardial infarction (STEMI) in the Critical Coronary Care Unit (CCCU) of a tertiary center with Mediterranean climate from July 2011 to September 2022. We analyzed the influence of the seasons on the incidence and characteristics of ACS. Results We enrolled a total of 1668 patients: 431 in Winter, 382 in Spring, 405 in Summer and 450 in Autumn, with the baseline characteristics summarized in Table 1. There were no differences in baseline characteristics among the 4 seasons, except for the higher prevalence of obesity in Autumn. There was no statistically significant difference in the incidence of STEMI among seasons, although numerically the highest incidence was recorded in Autumn. The occurrence of ACS was not different according to age or sex. ACS complications were not statistically different among seasons with similar incidence of ventricular arrythmias (VT, VF), invasive mechanical ventilation support, need for inotrope/vasopressor support or development of de-novo atrial fibrillation. In-hospital mortality is less frequent in Autumn, but the differences did not reach statistical significance. Conclusions In this Mediterranean climate cohort, STEMI incidence was higher in Autumn, although no differences in clinical profile or outcomes were found among seasons.