symptomatic dilated cardiomyopathy were studied in order to evaluate the effect of long term sympathetic beta-blockade with metoprolol. Clinical evaluation, stress test, two-dimensional echocardiography, 24 hour ambulatory electrocardiography and hemodynamic assessment with Swan-Ganz catheter were performed before enrollment in the study. Patients were randomly assigned to the relative placebo (8 pts) or metoprolol group (12 pts) in a single-blind fashion. The placebo group received standard therapy (digitalis, diuretics, vasodilators and anticoagulants as needed), while the metoprolol group, along with standard therapy received low-dose beta-blockade, starting with 6.25 mg twice daily and then doubling every 4 days on the two daily administrations. The therapeutic end-point was 100 mg. Patients received less than 100 mg if their systolic blood pressure was less than 100 mmHg or if their resting heart rate was less than 55 beats/min. Patients were clinically assessed every month and a 24-hour electrocardiography, echocardiography and hemodynamic control was repeated after six months. In the metoprolol group there was one sudden death and two drop-outs.(ABSTRACT TRUNCATED AT 250 WORDS)