Acute myocardial infarction (AMI) is a chief cause of death worldwide. The best strategy to limit myocardial damage is to perform an early coronary reperfusion. However, despite reperfusion, the size of infarctions is many times large. Infarct size has been recently shown to be a strong predictor of future cardiovascular events and mortality. Therefore interventions aimed at reducing infarct size are the matter of intense research; but despite great efforts, no therapy has been shown to consistently limit infarct size.~ß-blockers are a class of drugs that have been used to treat cardiovascular conditions for several decades. β-blockers reduce mortality when administered after an AMI, and are a class IA indication in this context. What remains unclear is what timing and route of β-blocker administration gives the maximum cardioprotective effect. In particular, whether early β-blocker administration is able to reduce infarct size is a subject of debate. Recent experimental data suggest that the β1 selective blocker metoprolol is able to limit the area of necrosis only when administered before reperfusion.~The objective of this trial is to determine whether the administration of intravenous pre-reperfusion metoprolol might reduce infarct size.
The purpose of this study is to test whether early pre-reperfusion metoprolol administration in patients suffering and acute myocardial infarction might reduce the size of myocardial necrosis.