Reentrant tachycardia using two discrete atrioventricular nodes and a concealed atriofascicular pathway.

We describe a case of reentrant supraventricular tachycardia using two discrete atrioventricular (AV) nodes in the antegrade direction and a concealed atriofascicular pathway in the retrograde direction in a 21-year-old woman with superior-inferior ventricles and ventricular inversion. Using the Carto endocardial mapping system, two discrete AV nodes were identified as well as a separate decremental AV pathway located midway between the two nodes. Ablation of the separate pathway resulted in elimination of inducible tachycardia without loss of either AV node.