[Anterograde tachycardia caused by the antitachycardia mechanism in a DDD pacemaker]

If there is a demonstrable ventriculo-atrial conduction at the time of a DDD pacemaker implantation, the possibility of a pacemaker mediated tachycardia is always present. The latest technological advances tries to solve this problem by the refractory time programmability and specially by the automatic extension of the atrial refractory period. A new and special mode of premature ventricular contraction-synchronous atrial stimulus has been developed as an additional and more effective mechanism anti pacemaker mediated tachycardia. We present one case in which this anti pacemaker mediated tachycardia mode just unchains one tachycardia. The understanding of this tachycardia doesn't offer difficulties and the correction would be made by different steps.