The efficacy and safety of esmolol, a titratable intravenous beta-adrenergic blocking agent with a short elimination half-life (t 1/2 = 9.0 min) was evaluated in a multicenter open-label study for the treatment of supraventricular tachyarrhythmias (heart rate greater than 100 bpm). The study also investigated the feasibility of transferring patients from esmolol to alternate oral antiarrhythmic agents without loss of therapeutic response. Of the 113 patients studied, 95 (84%) achieved therapeutic response (reduction in heart rate of 15% or more or conversion to sinus rhythm). Most of these patients (93%) achieved the therapeutic response at esmolol doses of 200 micrograms/kg/min or lower. Transfer from esmolol to an oral antiarrhythmic agent(s) was studied in 76 patients. Alternate antiarrhythmic agents used in this study were digoxin (N = 25), propranolol (N = 21), verapamil (N = 10), metoprolol (N = 11), quinidine (N = 2), and a combination of two antiarrhythmic agents (N = 7). Sixty-seven (88%) patients were successfully transferred to oral antiarrhythmic agents without loss of the therapeutic response obtained with esmolol. The most frequent adverse effect observed during the study was hypotension, which resolved quickly (16 +/- 14 min) either by decreasing the dose or by discontinuation of esmolol infusion. This study supports previous observations concerning the safety and efficacy of esmolol in the treatment of supraventricular tachyarrhythmias. Furthermore, it demonstrates that the majority of patients successfully treated with esmolol can be safely and effectively transferred to oral therapy with alternate antiarrhythmic agents.