METHODS, ANATOMY AND MECHANISMS OF RADIOF REQUENCY CURRENT ABLATION OF AV NODAL REENTRANT TACHYCARDIA

Three different methods of radiofrequency catheter ablation of AV noda l reentrant tachycardia were investigated in 128 patients. Results, re lapses, and complications using anterior approach (n = 15), moved cath eter (n = 20), and posterior-inferior approach (n = 93) were compared. Eight mechanisms of ablation of AV nodal reentrant tachycardia were d istinguished: 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) bo th pathways (n = 13), 6) Ablation of fast and modulation of slow pathw ays (n = 4), 7) ablation of slow and modulation of fast pathways (n = 12), and 8) ablation of both pathways (n = 3). The criteria of diagnos is of these mechanisms and a mapping grid of Koch's triangle were prop osed. The fast pathway is located in the anterior septum in a region w ith identical amplitudes of atrial and ventricular deflections and the slow pathway could be found posteriorily in a more ventricular locati on. The anatomical location of the slow pathway differed more widely t han 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 relapse s in 12 patients during control studies 30 min, 3-5 days, and 3-6 mont hs 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 A V nodal reentrant tachycardia wilt be the method of first choice in pa tients with recurrent tachycardia.