Beta-blocker therapy significantly reduced a composite endpoint of all-cause mortality and major adverse cardiovascular events compared with no therapy in patients with myocardial infarction (MI) and preserved or mildly reduced left ventricular ejection fraction (LVEF), according to results from the BETAMI and DANBLOCK trials. Findings are published in the New England Journal of Medicine.
Evidence for beta-blocker use after MI was established before modern reperfusion and secondary prevention strategies. While beta-blockers are strongly recommended in MI with reduced LVEF, their benefit in patients with preserved or mildly reduced LVEF (≥40%) without heart failure has been uncertain.
To address this, the Norwegian BETAMI and Danish DANBLOCK trials, two randomised open-label, blinded-endpoint studies with near-identical designs, were combined. Patients with LVEF ≥40% and no clinical heart failure were enrolled within 7 days (BETAMI) or 14 days (DANBLOCK) of MI and randomised 1:1 to long-term beta-blocker therapy or no beta-blocker. The primary endpoint was a composite of all-cause mortality, new MI, unplanned coronary revascularisation, ischaemic stroke, heart failure, or malignant ventricular arrhythmias.
Among 5,574 participants (median age 63 years; 20.8% women), 10.5% had prior coronary artery disease and 8.4% were already on beta-blockers. After a median follow-up of 3.5 years, the primary endpoint occurred in 14.2% of patients on beta-blockers versus 16.3% without. All-cause mortality rates were similar (4.2% vs. 4.4%), but new MI was significantly lower with beta-blockers (5.0% vs. 6.7%). No clear differences were observed in heart failure, malignant ventricular arrhythmias, revascularisation, or ischaemic stroke.
Safety outcomes were reassuring: within 30 days, a composite of all-cause mortality, MI, heart failure, or malignant arrhythmia occurred in 0.8% of the beta-blocker group and 1.1% of controls, with similarly low rates of serious adverse events overall.
Study authors conclude that long-term beta-blocker therapy reduced the composite of all-cause mortality and major cardiovascular events, particularly new MI. These findings suggest that beta-blockers remain relevant in contemporary MI management, even for patients without reduced LVEF or heart failure, though results should be interpreted alongside ongoing and recent trials to guide practice.
Source: European Society of Cardiology
Image Credit: iStock
