Original Title: Early Intravenous Beta-Blockers in Patients with ST-Segment Elevation Myocardial Infarction before Primary Percutaneous Coronary Intervention.
Reference: Roolvink V et al. J Am Coll Cardiol. 2016 Jun 14;67(23):2705-15.
The impact of endovenous beta-blockers before primary PCI has not been established yet. This is the first double blind multicenter trial, controlled with placebo, to test the effect of early beta-blocker administration before primary PCI in a population undergoing ST elevation myocardial infarction (STEMI).
All STEMI patients without atrioventricular block within 12 hours of symptom onset Killip class I or II, were randomized 1:1 to endovenous metoprolol (2 x 5 mg. bolus) vs. placebo before primary PCI.
Primary end point was infarct size measured by MRI at 30 days. Secondary end point were enzymatic infarct size and ventricular arrhythmia incidence. Safety end points were symptomatic bradycardia, symptomatic hypotension and cardiogenic shock.
A total of 683 patients (mean age 62 ± 12 years) were randomized to metoprolol (n=336) or placebo (n=346). Control MRI was performed in 342 patients (54.8% of the population).
Mean infarct size (percent of left ventricle) was not different between the groups:
- Metoprolol: 15.3 ± 11.0%
- Placebo: 14.9 ± 11.5%
p=0.616
Peak and area under the creatine kinase curve was not different, as wasn’t ejection fraction:
- Metoprolol: 51.0 ± 10.9%
- Placebo: 51.6 ± 10.8%
p=0.68
Malignant arrhythmia incidence was:
- Metoprolol: del 3.6%
- Placebo: 6.9%
p=0.050
End point safety rate not different between the groups.
Conclusion
In an unselected population undergoing STEMI, early administration of endovenous metoprolol before PPCI was not associated to a reduction of infarct size. Metoprolol did reduce arrhythmia incidence in the acute phase, and was not associated to adverse events.
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