Programmed rate-related interval stimulation proved to be a low-risk method when applied to 74 patients with drug-resistant ventricular tachycardia or runs of ventricular extrasystoles as precursors of tachycardia. Atrial flutter was converted to atrial filbrillation and sinus rhythm by atrial interval-related multiple stimulations. Tachycardias, which could not be terminated by simple or double stimulation, were successfully suppressed by sequential ventricular R-R related multiple stimulations. Rare-related stimulation has proved to be an alternative method of treating tachy-arrhythmias unresponsive to conventional means.