Automatic scanning extrastimulus pacemaker to treat ventricular tachycardia.

Many investigators have reported the use of various permanent pacemaking modes in the long-term management of patients with recurrent ventricular tachycardia. The three general types of antitachycardic pacemakers are: (1) underdrive; (2) burst; and (3) scanning pacemakers. Such devices have been activated externally or have had automatic activation. Each antitachycardic pacemaking modality has known technical and physiologic limitations. A serious limitation of dual-demand underdrive pacemakers is that they are usually successful only for tachycardias with a rate below 160 bpm because a random stimulus is needed for conversion. Therefore, this modality is seldom useful in patients with symptomatic sustained ventricular tachycardia in which rates are generally greater than 160 bpm and/or hemodynamic compromise occurs rapidly. Although others have reported the successful use of burst pacemakers in the control of ventricular tachycardia, this technique may cause acceleration of ventricular tachycardia and induction of ventricular fibrillation. Programmable automatic scanning pacemakers have been used successfully to treat paroxysmal supraventricular tachycardia and have been used recently in combination with antiarrhythmic agents to control ventricular tachycardia. This report outlines the use of an automatic scanning pacemaker alone for the treatment of symptomatic ventricular tachycardia in a patient who was unable to tolerate conventional antiarrhythmic medications.