Ventricular output failure in a DDD permanent pacemaker associated with increased atrial output.

Previous reports have described the occurrence of ventricular output failure in a permanent DDD pacemaker system related to an increase in the atrial output in the presence of low atrial lead impedance (Medtronic Synergyst/Synergyst II). This phenomenon is seen exclusively following atrial paced events and may potentially lead to significant bradyarrhythmia or ventricular asystole in a pacemaker dependent patient. We describe the occurrence of analogous behavior in a Medtronic Symbios 7006 generator.