The Association Between Acute Myocardial Infarction with Seasonal Variations and Admission Time

Background: There are contradictory results regarding the pattern of seasonal variations of acute myocardial infarction (MI). Documentation of such a pattern may contribute to identify new pathophysiological factors in the occurrence of MI. Therefore, the current study aimed at determining the association between MI and the admission season and time. Methods: The current cross sectional, retrospective study was conducted on 286 patients diagnosed with MI admitted to Imam Sajjad (a.s) hospital in Ramsar, Iran, in a 5-year period from 01 July, 2012 to 31 July, 2016. Data of patients including age, gender, and admission hours, months, and seasons were collected from their records. Information on temperature and humidity was collected from Ramsar weather forecast center (Iran). Data analysis was done by SPSS version 18 through statistical tests. Results: The mean age of the study subjects was 68.12 ± 6.44 years. The highest admission rate was in summer (30.1%) in terms of season, and it was 35% at 12:00 P.M to 6:00 P.M in terms of time. Admission peak hours were at 10:00 AM, 11:00 AM, 1:00 P.M, and 2:00 P.M, respectively. There was significant statistical difference between MI in terms of season, and temperature and humidity average (P < 0.00). Conclusions: There was a seasonal rhythm in admissions for acute MI in the study with an increase in summer and a decrease in winter. In most of the studies regarding the effect of seasonal variations on the occurrence of acute MI, only the effect of temperature was studied. Due to the relationship between humidity and the occurrence of acute MI in the current study, it is recommended to conduct further studies by considering the 2 variables.