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

We describe a case of reentrant supraventricular tachycardia using two disc rete atrioventricular (AV) nodes in the antegrade direction and a concealed atrio-fascicular pathway in the retrograde direction in a 21-year-old woma n with superior-inferior ventricles and ventricular inversion. Using the Ca rto endocardial mapping system, two discrete AV nodes were identified as we ll as a separate decremental AV pathway located midway between the two node s. Ablation of the separate pathway resulted in elimination of inducible ta chycardia without loss of either AV node.