ABSTRACT
BACKGROUND: Acute myocardial infarction (AMI) is usually associated with increased neutrophil count. However, it has not clearly been defined whether neutrophilia can cause myocardial injury. In this study, we hypothesized that absolute neutrophilia can predict the occurrence of congestive heart failure (CHF) after AMI. METHODS: A cross-sectional study was carried out on 312 patients with a diagnosis of AMI. Patients with a history of chest pain for more than 12 hours before admission, heart failure with Killip class III and IV, history of recent gastrointestinal bleeding, major trauma, infection, malignancy, renal failure and corticosteroid consumption were excluded. A blood sample was drawn for leukocyte count and an echocardiogram was obtained 4 days after admission. Congestive heart failure was defined as an ejection fraction less than 40% on echocardiogram or clinical heart failure according to the Framingham's criteria for diagnosis of heart failure. RESULTS: After excluding 19 patients, data for 293 patients were analyzed. Among them, 152 (51.9%) patients developed new onset CHF. Two hundred and two patients (68.9%) had neutrophilia (neutrophil count >7500/mic/lit). The risk of developing heart failure was higher in patients with neutrophilia (OR = 2.32; 95% CI = 1.33-4.03, P = 0.000). There was a negative correlation between ejection fraction and neutrophil count (r = -0.191, P = 0.000). After adjustment for age, sex, serum creatinine level, peak enzyme CK-MB level and MI location, the relationship between the absolute neutrophil count and the presence of congestive heart failure remained significant (OR = 2.14; 95% CI = 1.19-3.84, P = 0.011). CONCLUSIONS: The study shows that the presence of absolute neutrophilia during the first 12 hours after AMI can predict the occurrence of CHF. This association may help identify high-risk individuals, who might benefit from more aggressive interventions.