Influence of the previous use of β-blockers on the early clinical course of acute coronary syndromes.

Recent studies have recently questioned the current role of β-blockers in myocardial infarction. Our purpose is to analyze the influence of the previous use of β-blockers on the early course of patients admitted because of acute coronary syndrome (ACS). We analyzed the data of 37.359 patients included in the ARIAM-Andalucia Registry. Of them, 7759 (20.8%) were previously receiving β-blockers. BB patients were older, more often female, had more risk factors and vascular disease, and less often had an ST-elevation myocardial infarction. In the unadjusted analysis, BB patients less often had ventricular fibrillation or atrioventricular block, and more often a Killip classification >1, and no difference of in-hospital mortality (5.7 vs 5.6%). After logistic regression analysis and propensity score matching, no differences in complications or mortality (odds ratio 0.997, 95% confidence interval 0.882-1.128) were found in relationship to previous β-blockers. In conclusion, we find that the previous administration of β-blockers is not an independent predictor of the early prognosis of ACS.