[Methods, topography and mechanisms of radiofrequency ablation of AV-nodal reentry tachycardia].

Three different methods of radiofrequency catheter ablation of AV nodal reentrant tachycardia were investigated in 128 patients. Results, relapses, and complications using anterior approach (n = 15), moved catheter (n = 20), and posterior-inferior approach (n = 93) were compared. Eight mechanisms of ablation of AV nodal reentrant tachycardia were distinguished: 1) Ablation of fast pathway (n = 8), 2) of slow pathway (n = 22), 3) modification of fast (n = 12), 4) slow (n = 54), or 5) both pathways (n = 13), 6) Ablation of fast and modulation of slow pathways (n = 4), 7) ablation of slow and modulation of fast pathways (n = 12), and 8) ablation of both pathways (n = 3). The criteria of diagnosis of these mechanisms and a mapping grid of Koch's triangle were proposed. The fast pathway is located in the anterior septum in a region with identical amplitudes of atrial and ventricular deflections and the slow pathway could be found posteriorly in a more ventricular location. The anatomical location of the slow pathway differed more widely than the location of the fast pathway. The best method with lowest risk could be recommended as the ablation of the slow pathway. This method implicated the lowest incidence of complications. We observed relapses in 12 patients during control studies 30 min, 3-5 days, and 3-6 months after first ablation procedure. These arrhythmias could be ablated in a second attempt in eight and in a third procedure in four patients. With increasing experience the radiofrequency catheter ablation of AV nodal reentrant tachycardia will be the method of first choice in patients with recurrent tachycardia.