Programmed stimulation for long-term treatment and non-invasive investigation of recurrent tachycardia.

Eleven patients with recurrent tachycardia refractory to drugs were treated by a pacemaker system that consisted of an implanted QRS triggered stimulator activated by the application of stimuli to the patient's skin. These skin stimuli are derived by a small control box carried about in the pocket or handbag and which the patient holds in his hands to make contact with the electrode plates during a tachycardia attack. If the heart rate is higher than the preset value on the control box, timed stimuli are delivered to the skin. The tachycardia is stopped by a premature ventricular contraction induced during the "termination window", a period that occurs very soon after the refractory period. The skin impulses continue to be delivered until the tachycardia stops. The eleven patients were followed up for more than 2 1/2 years and about 2000 episodes were reliably stopped by this pacemaker system. Patients do not feel the skin stimuli and there were few complications.