Twin atrioventricular node associated with interruption of the inferior vena cava and atrioventricular nodal reentrant tachycardia.

We report the case of a patient exhibiting symptomatic junctional bigeminy associated with twin atrioventricular (AV) node and an anomaly in the inferior vena cava. The patient evidenced twin AV node and complete interruption of the inferior vena cava, with azygos continuation. The catheters for mapping of the AV junctional area and ablation were accessed via jugular and subclavian venous approaches, and azygos venous approach via the femoral vein. Twin AV node was diagnosed by (1) the existence of 2 discrete non-preexcited QRS morphologies of junctional bigeminy, (2) decremental anterograde and retrograde conduction, and (3) inducible AV nodal reentrant tachycardia. Atrioventricular nodal reentrant tachycardia and bigeminal rhythm were eliminated by ablation of the retrograde pathway. The postablation rhythm was a regular junctional rhythm, without tachycardia.