The aim of this study is to describe the impact of early treatment with metoprolol on prognosis during 1 year of follow-up in patients with suspected acute myocardial infarction (AMI) and indirect signs of congestive heart failure (CHF). Patients aged 40-74 years who presented within 48 hours of onset of symptoms raising suspicion of AMI were assessed for inclusion. All patients participated in the Göteborg Metoprolol Trial and had indirect indices of CHF according to various clinical criteria. As soon as possible after hospital admission, patients received either placebo or metoprolol (15 mg) divided into 3 intravenous injections, then oral treatment, 200 mg daily for 3 months. Thereafter, most patients in both treatment groups received metoprolol in an open manner. Among the 1,395 randomized patients, 262 (19%) had signs of mild-to-moderate CHF before randomization. Of these, 131 were randomized to metoprolol and 131 to placebo. During the first 3 months, mortality was 10% among patients randomized to metoprolol versus 19% among patients randomized to placebo (p = 0.036). The corresponding figures for the first year were 14% and 27%, respectively (p = 0.0099). Patients randomized to placebo who showed signs of CHF had a 1-year mortality rate of 28% compared with 10% among patients without such signs (p <0.001). The results suggest that early treatment with metoprolol markedly reduces mortality in patients having suspected AMI and signs of CHF.