Catheter ablation of atrioventricular accessory pathway with decremental properties connecting to the tricuspid annulus.

A 65-year-old male with Wolff-Parkinson-White syndrome presented with atrial fibrillation. The patient was found at the electrophysiological study to have two accessory pathways, a Kent fiber and an atrioventricular accessory pathway with decremental properties. The latter pathway conducted exclusively in the antegrade conduction and the ventricular insertion site was the tricuspid annulus. Both accessory pathways were successfully abolished by radiofrequency catheter ablations at the tricuspid annulus. We propose that an atrioventricular accessory pathway with decremental conduction may have various forms concerning not only sites of origin, but also sites of insertion.