Seasonal Variations of Heart Failure and Acute Coronary Syndrome in a Referral Center of Heart Diseases in Ahvaz, Southwest of Iran

 Despite the role of hot weather and activity at high temperatures in physical and environmental stress influencing the occurrence or recurrence of heart disease, the role of seasonal variations in temperature in this disease has not been well studied.

 This study aimed to investigate the relation of seasonal variations in temperature to the number of patients with ischemic heart disease and heart failure (HF).

 We extracted data, including file number, diagnosis, age, gender, hospitalization date, and discharge date, from the medical files of patients admitted to a referral center of heart diseases in a tropical region from 2013 to 2015.

 Diagnosed and studied patients (n = 4,041) were as follows: 625 (patients with HF), 2410 (patients with unstable angina), and 1006 (patients with myocardial infarction). A total of 57% of patients were male, and 43% were female. The average number of patients per day (P/d) in the cold season was higher than in other seasons (5.89 versus 5.53 in the moderate season and 5.18 during the warm season). The mean length of hospitalization for patients with myocardial infarction (MI) and HF in the cold season was longer than in other seasons, and this difference was statistically significant (P = 0.035 and 0.021, respectively).

 All hospitalizations occurring with these diagnoses in cold seasons are longer, increasing the burden on the health care system. There are considerable seasonal variations in HF hospitalization and mortality. Immunization against pneumococcus and influenza and also more care are recommended in HF patients. There is a need for a season-based approach for better handling of acute coronary syndrome (ACS).