Left Ventricular Ejection Fraction 1 Year After Acute Myocardial Infarction Identifies the Benefits of the Long-Term Use of β-Blockers Analysis of Data From the KAMIR-NIH Registry

BACKGROUND: beta-Blockers can improve prognosis after acute myocardial infarction. However, it remains unclear how long beta-blockers should be prescribed. METHODS: We included patients from the prospective, nationwide Korea Acute Myocardial Infarction Registry-National Institutes of Health registry and collected data on beta-blockers and left ventricular ejection fraction (LVEF) at 1-year follow-up. Patients were stratified into 2 groups: 1001 patients with a 1-year LVEF RESULTS: A total of 3177 patients received beta-blockers at 1 year, and 151 patients died during the 2-year follow-up from 1 year after index hospitalization. beta-Blockers showed survival benefits in patients with a 1-year LVEF<50% (log-rank P=0.001) but not in those with a 1-year LVEF >= 50% (log-rank P=0.311). After adjusting covariates, beta-blockers were associated with a 51% reduction in mortality in patients with a 1-year LVEF<50% (P=0.020) but not in their counterparts (P=0.322). Indeed, there was a prognostic interaction between the use of beta-blockers at 1 year and 1-year LVEF (P for interaction=0.004). CONCLUSIONS: Use of beta-blockers at 1-year follow-up after acute MI was associated with improved outcomes in patients with an LVEF50% at 1 year. This study provides valuable information about differential responsiveness to beta-blockers according to 1-year LVEF and might suggest the proper duration of beta-blockers after acute MI. REGISTRATION: URL: http://cris.nih.go.kr/cris/en/; Unique identifier: KCT0000863. GRAPHIC ABSTRACT: A graphic abstract is available for this article.

Automated summary

The study showed that the use of beta-blockers at 1-year follow-up after acute MI was associated with improved outcomes in patients with LVEF<50%. Specifically, beta-blockers were found to be beneficial in reducing mortality in patients with LVEF<50%, indicating differential responsiveness to beta-blockers based on 1-year LVEF levels.