Therapeutic pacing in tachyarrhythmias by implanted pacemakers.

Termination of tachyarrhythmias by electrical stimulation has been demonstrated by clinical and experimental evidence. Implantable devices for repetitive use in long-term therapy are so far not readily available. Twelve patients with drug resistant ventricular (3) or supraventricular (accessory pathway (2), atrial flutter (3), junctional tachycardia (3), supraventricular tachycardia (1) tachyarrhythmias are reported in whom, after electrophysiological analysis of the individual tachycardia, a specially designed stimulation system was implanted. Cardiac pacing was performed in the right atrium or ventricle. Stimulation rate was in the range of 150-1016/min. In automatic ECG-controlled devices (2 patients), the number and length of cardiac cycles served as parameters for discharging the stimulation circuit. In 10 patients the antitachycardia-pacemaker was in use as a patient-activated or externally triggered device or as a fixed rate unit. After pacemaker implantation we observed a significant decrease in incidence and/or duration of tachycardic episodes in all patients. In two patients atrial pacing (80 and 90/min) suppressed tachycardias completely. Additional antidysrhythmic drug therapy was necessary in 11 out of our 12 patients. It is concluded that cardiac stimulation with implanted antitachycardia pacemakers can be an efficient long-term antitachyarrhythmic therapy in selected patients.