Immediate β-Blockade in Patients With Myocardial Infarctions: Is There Evidence of Benefit?

Study objective

The American Heart Association recommends the initiation of β-blockade to all patients with an ST-segment elevation myocardial infarction (STEMI) without contraindications to β-blocking agents. The present study seeks to systematically review the medical literature to determine the efficacy of treating STEMI patients with a β-blocker within the first 24 hours.

Methods

We searched databases for articles through MEDLINE with the PubMed interface and from 1966 through May 2009 and EMBASE from 1980 to August 2009 with the Ovid Technologies interface, using a search strategy derived from the following PICO (Patient-Intervention-Comparator-Outcome) clinical question: In patients presenting with STEMI (P), does immediate treatment with β-blockers (I) followed by standardized care beginning on day 2 or 3 compared with placebo or no treatment followed by standardized care on day 2 or 3 (C) reduce the risk of death, reinfarction, or cardiogenic shock (O)? The methodological quality of the studies was assessed.

Results

From more than 2,000 references identified in the search, only a single randomized trial met the inclusion criteria. There were no statistically significant differences in mortality; the relative risk for the combined endpoint (mortality and reinfarction) was 0.67 (95% confidence interval 0.44 to 1.03) at 6 days and 0.74 (95% confidence interval 0.53 to 1.06) at 6 weeks. Outcomes for cardiogenic shock were not reported.

Conclusion

Evidence from a single randomized trial failed to demonstrate a reduction in mortality or reinfarction with administration of β-blocker within the first 24 hours after STEMI.