Automatic activity of a decremental long atrioventricular accessory pathway: an unusual feature.

The electrophysiological properties of decremental atrioventricular and atriofascicular pathways are not completely understood. We report the case of a patient with fast reentrant tachycardia due to a decremental long atrioventricular pathway, who showed a slow automatic tachycardia arising from the same pathway that was successfully eliminated by radiofrequency catheter ablation.