Seven male patients suffering from angina pectoris with spontaneous premature ventricular beats were given oral ibopamine 50 mg t.i.d. for 5 consecutive days, after at least 6 days of observation under basal conditions. A number of clinical parameters were explored during the basal and treatment periods, including repeated 24-hour Holter recordings in each case. The heart rate, expressed as mean hourly rate, minimum and maximum values per observation period, and nocturnal value, showed no clinically or statistically significant change with treatment. There was no worsening of pre-existing arrhythmias or chest pain. All other test parameters remained unchanged. This confirms the excellent tolerance of ibopamine in patients with ischaemic heart disease.