Objective β-blockers are the standard treatment for myocardial infarction (MI) based on evidence from the pre-thrombolytic era. The aim of this study was to examine the effect of β-blocker treatment in patients with acute MI and preserved systolic function in the era of percutaneous coronary intervention (PCI).

Methods We analysed a multicentre registry and identified 3019 patients who presented with acute MI between 2004 and 2009. Patients were treated with PCI, had left ventricular EFs ≥50% according to echocardiograms that were performed during the index PCI, and were alive at the time of discharge. The association between β-blocker use after discharge and mortality (all-cause death and cardiac death) within 3 years was examined.

Results Patients who were not treated with β-blockers (n=595) showed higher rates of all-cause death and cardiac death compared to patients treated with β-blockers (10.8% vs 5.7%, p<0.001, 7.6% vs 2.6%, p<0001). The multivariate Cox proportional hazards model showed that β-blocker treatment was associated with a significant reduction in all-cause death (adjusted HR 0.633, 95% CI 0.464 to 0.863; p=0.004) and cardiac death (adjusted HR 0.47, 95% CI 0.32 to 0.70; p<0.001). Comparable results were obtained after propensity score matching.

Conclusions β-blocker treatment was associated with reduced long term mortality in patients with acute MI and preserved systolic function who received PCI.