ORTHODROMIC PACEMAKER CIRCUS MOVEMENT TACHYCARDIA

We report on the case of a 33-year-old woman with sick sinus syndrome who had an orthodromic pacemaker circus movement tachycardia (PCMT), with antegrade atrioventricular (AV) conduction and a retrograde pathway by means of a DDD (AV universal) pacemaker. This PCMT was provoked and sustained by premature ventricular contraction-synchronous atrial stimulation (PVC-SAS), which is a new feature for the prevention of anti-dromic PCMTs. The conditions for occurrence of this tachycardia were: (1) PVC-SAS; (2) atrial undersensing; (3) first degree AV block. Recommendations for prevention of this pacemaker-mediated tachycardia are given.