Information from stimulation studies in human beings with tachycardia has resulted in the application of cardiac pacing in the treatment of such patients. Short-term pacing is especially useful in patients with atrial flutter. Long-term pacing with use of chronically implanted units can be applied to patients with different types of supraventricular and ventricular tachycardia. In these patients careful electrophysiologic studies are required before the pacing device is implanted. New developments enabling automatic and more individually designed modes of pacing are urgently needed.