Right posterior atrioventricular ring: a location for different types of atrioventricular accessory connections.

We present an unusual case of a 28-year-old female patient with recurrent episodes of tachycardias due to participation of two accessory connections located in the posterior tricuspid annulus. Both connections were of the atrioventricular type, the one with non decremental fast conducting properties at the right posteroseptal area, the other with node-like properties at the posterolateral tricuspid ring. Both pathways were successfully ablated transvenously with radiofrequency energy application at the same session. Implications about a common embryological origin of the two pathways as well as review of the literature for similar cases are presented.