Abstract :
Background
The beneficial effects of β-blockers on longterm outcome after acute myocardial infarction were shown before the introduction of thrombolysis and angiotensin-converting-enzyme (ACE) inhibitors. Generally, the patients recruited to these trials were at low risk: few had heart failure, and none had measurements of left-ventricular function taken. We investigated the long-term efficacy of carvedilol on morbidity and mortality in patients with leftventricular dysfunction after acute myocardial infarction treated according to current evidence-based practice.
Methods In a multicentre, randomised, placebo-controlled trial, 1959 patients with a proven acute myocardial infarction and a left-ventricular ejection fraction of ≤40% were randomly assigned 6·25 mg carvedilol (n=975) or placebo (n=984). Study medication was progressively increased to a maximum of 25 mg twice daily during the next 4–6 weeks, and patients were followed up until the requisite number of primary endpoints had occurred. The primary endpoint was all-cause mortality or hospital admission for cardiovascular problems. Analysis was by intention to treat.
Findings
Although there was no difference between the carvedilol and placebo groups in the number of patients with the primary endpoint (340 [35%] vs 367 [37%], hazard ratio 0·92 [95% CI 0·80–1·07]), all-cause mortality alone was lower in the carvedilol group than in the placebo group (116 [12%] vs 151 [15%], 0·77 [0·60–0·98], p=0·03). Cardiovascular mortality, non-fatal myocardial infarctions, and all-cause mortality or non-fatal myocardial infarction were also lower on carvedilol than on placebo.
Interpretation
In patients treated long-term after an acute myocardial infarction complicated by left-ventricular systolic dysfunction, carvedilol reduced the frequency of all-cause and cardiovascular mortality, and recurrent, non-fatal myocardial infarctions. These beneficial effects are additional to those of evidence-based treatments for acute myocardial infarction including ACE inhibitors.
