Continuous ECG monitoring is a useful method to evaluate the efficacy of antiarrhythmic drugs. The aim of our study was to evaluate the effects of amiodarone (400 mg day-1 for seven days and then 200 mg day-1, five days a week, for 60 days) in 20 patients with chronic ischaemic heart disease ascertained by stress test, thallium-201 myocardial scintigraphy and coronary angiography and with qualitatively and quantitatively similar cardiac arrhythmias in two continuous ECG monitoring sessions performed before starting treatment. All patients were previously on treatment with isosorbide 5-mononitrate (Is-5-Mn). Patients underwent two ECG monitoring sessions for 48 h, with an ICR instrument with two leads, first during pharmacological treatment with Is-5-Mn plus placebo and then after 60 days on treatment with Is-5-Mn and amiodarone. Heart rate decreased significantly with amiodarone (from 76.9 to 69.5 beats min-1) as did premature ventricular complexes (from 4686 to 329 day-1), ventricular couplets (from 154.3 to 5.0 day-1), ventricular tachycardia runs (from 91.7 to 0). ST segment depression more than 1.5 mm was present for 93.8 min day-1 on Is-5-Mn plus placebo, and was significantly less frequently observed (for 13.8 min day-1) on Is-5-Mn plus amiodarone. Finally, transient episodes of ischaemia, both symptomatic and asymptomatic, diminished on amiodarone from 22 to 9 day-1 in a significant way. In conclusion, amiodarone is a useful drug to obtain a reduction of ventricular arrhythmias and symptomatic and asymptomatic episodes of ischaemia in patients with ischaemic heart disease.