BackgroundBeta-blockers are the standard treatment for acute coronary syndrome (ACS) based on evidence from the prethrombolytic era.We sought to examine the effect of beta-blocker treatment on patients without heart failure or left ventricular systolic dysfunction after ACS in the contemporary percutaneous coronary intervention (PCI) era. MethodsWe systematically searched PubMed, Web of Science, Cochrane Library, ClinicalTrials.gov and Google Scholar for studies comparing beta-blockers versus no beta-blockers in ACS patients in the contemporary PCI era. The primary outcome was all-cause death. Pooling unadjusted and multivariable adjusted results were calculated under random-effects models. ResultsData from 15 studies (n=205,672), including 1 randomized trial, were analysed. Compared with no beta-blockers, beta-blocker therapy at discharge may reduce the risk of all-cause death (odds ratio [OR] 0.66, 95% confidence interval [CI]: 0.50–0.86; I2=81.9%). Subgroup analysis according to single or multicentre studies indicated similar results. Prospective studies suggested that all-cause death was less common in the beta-blocker group. After multivariable adjustment, a lower risk of all-cause death was still observed with beta-blockers (OR: 0.74, 95% CI: 0.59–0.94; I2=40.1%). No differences existed in major adverse cardiovascular events (MACE), cardiac death, myocardial infarction, heart failure, revascularization or stroke, before and after multivariable adjustment. ConclusionsIn patients without heart failure or left ventricular systolic dysfunction after ACS in the contemporary PCI era, beta-blocker therapy may still be beneficial due to a potential reduced risk of all-cause death.