White blood cell count and the occurrence of silent ischemia after myocardial infarction

Background: Inflammation plays a role in the pathogenesis of atherosclerosis. Attempts are made to use markers of inflammation as prognostic factors in coronary artery disease and acute coronary syndromes. The correlation between inflammation and silent postinfarction ischemia is unknown. Methods: The study population consists of 104 asymptomatic patients who had uncomplicated Q-wave myocardial infarction within 6 months prior to the enrollment. After the white blood cell (WBC) count was assessed, the population was divided into two groups: group I comprising 48 patients with WBC less than or equal to 7.0 x 10(3)/mul and group II comprising 56 patients with WBC > 7.0 x 10(3)/mul. Twenty-four-hour Holter monitoring was performed to detect the presence of silent ischemia. Results: Eighty-eight silent ischemic episodes were recorded. Ischemia on Holter monitoring was detected in 47 patients (84%) from group II and in five patients (9%) in group I (P < 0.01). We have found a significant positive correlation between WBC count and the number of ischemic episodes (r = 0.25), their maximal amplitude (r = 0.39), duration (r = 0.34), and total ischemic burden (r = 0.36). In multivariate analysis leucocytosis proved to be the only parameter independently correlated with the presence of silent ischemia. Conclusion: Postinfarction asymptomatic patients with increased WBC count are more likely to have residual ischernia.