Decremental properties of a concealed nodoventricular pathway

IntroductionThe decremental properties of the nodoventricular pathway (NVP) are uncertain.Methods and ResultsDuring short RP supraventricular tachycardia, a His‐refractory premature ventricular contraction (PVC) consistently terminated the tachycardia without atrial capture immediately after the PVC. Whereas a slightly earlier PVC failed to reset the subsequent His but terminated the tachycardia without atrial capture one cycle later.ConclusionThese observations are diagnostic of slow‐fast atrioventricular nodal reentrant tachycardia (AVNRT) with a bystander concealed‐NVP and can be explained by decremental properties in the NVP itself; greater prematurity of the PVC resulted in more decremental conduction over the NVP, causing the AVNRT termination one cycle later.