The impact of antitachycardia pacing with defibrillation

Chronic recurrent ventricular tachycardia (VT) can be reproducibly terminated by programmed endocardial right ventricular stimulation. However, antitachycardia pacing can be associated with possible acceleration of VT, while frequent episodes of VT and patient discomfort can limit treatment by an implantable cardioverter defibrillator (ICD). The combined use of antitachycardia pacing and the AICD (automatic implantable cardioverter defibrillator) was evaluated in 6 out of 51 patients (age 57 +/- 11 years) in whom the AICD had been implanted because of recurrent VT. In each instance VT could be terminated by temporary overdrive pacing. The interactive mode of VT termination by a pacemaker (Tachylog) as well as by the AICD was assessed after implantation. In the automatic mode, the Tachylog functioned as a bipolar, ventricular inhibited (VVI) device with antitachycardia burst stimulation capability, allowing two to five stimuli at intervals of 260-300 ms and one or two interventions. During follow-up of 47 +/- 24 months, the Tachylog terminated VT reliably 50-505 times per patient. When burst stimulation accelerated VT, termination was achieved by AICD discharge. Thus, drug resistant VT can be terminated by antitachycardia pacing to avoid patient discomfort. In the event of tachycardia acceleration, VT was terminated by the AICD. A universal pacemaker-defibrillator should combine antibradycardia and antitachycardia pacing with back-up cardioversion defibrillation.