We used the combination of an antitachycardia automatic ventricular pacemaker with the automatic
implantable cardioverter-defibrillator in two patients with sustained, recurrent,
drug-resistant
ventricular tachycardias in whom a surgical ablation was not indicated. The indications for the combined use of the two systems were the possibility to control: a) the
ventricular tachycardias with ventricular programmed stimulation; b) the arrhythmias which might eventually degenerate into
ventricular flutter or fibrillation (as a result of anti-
tachycardia pacing) with the
defibrillator. To avoid any possible interference between the two systems we used the following protocol: a) endocardial bipolar pacing; b) the sensing
electrodes of the
defibrillator were placed as far as possible from the endocardial one; c) a suitable programming of the pacemaker output; d) a careful selection of the anti-
tachycardia pacing programme (burst rate inferior to the cut-off rate of the cardioverter-
defibrillator and/or a duration of the burst pacing inferior to the
arrhythmia sensing time of the
defibrillator); e) use of cardioverter-
defibrillators with a high cut-off rate. We never observed, during the follow-up (11 and 4 months, respectively), interference between the two systems. Both patients had
ventricular tachycardia recurrences (51 and 3 episodes, respectively). The arrhythmias were correctly detected and interrupted by the pacemaker without the intervention of the
defibrillator. These data confirm the feasibility of the combined use of the two systems in patients with
ventricular tachycardias and, in selected cases, this approach is preferable. The anti-
tachycardia pacemaker counteracts some limitations of the
defibrillators available at present. It offers a protection against
bradyarrhythmias and allows a more precise storage of arrhythmic events. The anti-
tachycardia pacemaker often controls
ventricular tachycardias without the intervention of the
defibrillator, thus giving the same a longer life-span and allowing patients to avoid the
shock.