The efficacy of beta-blockade after myocardial infarction (MI) has been investigated in a series of studies. When beta-blockers are used during the first hours after the onset of MI, a reduction in infarct size, mortality, and nonfatal reinfarction may occur. Bisoprolol is a highly beta1-selective beta-blocker, without intrinsic sympathomimetic activity (ISA), and with a plasma elimination half-life of 10-12 h, permitting treatment with one daily dose. Because no experience with bisoprolol was available in MI, its safety and efficacy were studied in two open, uncontrolled pilot studies. The first study was a dose-finding study in 37 patients with a 3-day-old MI. Bisoprolol was given intravenously and carefully titrated in steps of 1 mg up to a cumulative maximum dose of 5 mg. Subsequently, the patients received 10 mg of oral bisoprolol once daily (o.d.) until the end of the study. Based on the results of this first pilot study, a second pilot study was performed in which bisoprolol was given within the first 6 h after the onset of MI. Intravenous (i.v.) bisoprolol was titrated in two steps of 2.5 mg each, directly followed by 10 mg of oral bisoprolol o.d. The aim of this study was to investigate the influence of i.v. and subsequent oral bisoprolol on central hemodynamics. The results of these studies demonstrate that i.v. and subsequent oral administration of bisoprolol is well tolerated and indicate that the selected dose regimen is hemodynamically safe.