The relation between seasonal variation and mortality in patients with ST elevation myocardial infarction

Abstract

Aim: Acute vascular events show a circadian rhythm and daily variation. Previous studies demonstrated that ST segment elevation myocardial infarction (STEMI) increases in winter season; however, the prognosis of the patients that presented at different seasons has not been investigated yet. In this study we investigated the seasonal mortality variation of the patients who underwent primary percutaneous coronary intervention (PCI) for STEMI.

Materials and methods: We reviewed 2644 consecutive patients treated with primary PCI for STEMI. The date of STEMI was obtained from medical record. Patients were divided into groups depending on the season to the applicant. Group I (Autumn) had 570 (21.6%) patients, Group II (Winter) had 807 (305%) patients, Group III (Spring) had 734 (27.8%) patients and Group IV (Summer) had 533 (20.2%) patients.

Results: Age, sex and most of cardiovascular risk factors and angiographic features were comparable among groups. When compared to the group IV, in hospital reinfarction (re-MI) incidence was significantly higher in group II (3.2% vs 0.8%, p: 0.009). There were no differences between groups for in hospital and long term mortality, long term re-MI, target vessel revascularization and major adverse cardiac events (MACE).

Conclusion: This study showed that there were no seasonal variation in hospital and long-term mortality, long term re-MI and MACE after primary PCI for STEMI. Besides, in hospital re- MI incidence was significantly higher in winter when compared to the summer.