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According to ACC/AHA guideline, beta-blockers (BB) should be initiated within 24 hours in acute myocardial infarction (AMI) patients, without contraindications. But in the real clinical setting, the timing of BB administration varies. The purpose was to investigate the relation between the BB administration timing and the major adverse cardiovascular events (MACE).
We retrospectively analyzed the relationship between MACE and BB administration timing, based on medical records of total 599 AMI (249 STEMI, 350 NSTEMI) patients from May 2008 to April 2016 in a single center. The MACE including all-cause mortality, repeated revascularization and repeated admission because of heart failure were assessed for 8 years.
The 8-year MACE was not significantly different according to the BB administration timing when dividing the group by the BB administration timing of earlier than 12 hours vs later than 13 hours (7.8% vs 13.2%, p=0.142). And there were similar tendencies were found when analyzed based on the BB administration timing of 24, 36, 48 hours (p=0.479, p=0.223, p=0.385). And when analyzed based on the different BB and doses, there were also no significant differences in MACE.
But, there were significant differences of MACE when divided by the BB administration or not (12.0% vs 33.8%, p<0.001) as shown in Kaplan-Meier survival analysis (Figure).
Beta-blocker administration is an important factor for clinical outcome, but the initiation timing, classes, and doses can be individualized by the patients' medical condition.