CATHETER ABLATION OF THE ATRIOVENTRICULAR NODE USING RADIOFREQUENCY ENERGY

Background: Catheter ablation of the atrioventricular (AV) junction using stored direct current (DC) energy from a standard DC Cardioverter defibrillator was first reported in 1982. Since then many patients have been treated using this procedure for refractory supraventricular arrhythmias, usually atrial fibrillation and flutter. Undesirable thermal effects such as barotrauma and arcing are largely responsible for complications associated with the use of DC energy. This report details our experience of catheter ablation of the AV junction using radiofrequency (RF) energy in a series of 30 consecutive patients. Methods: RF ablations were performed using steerable Mansfield (Webster Laboratories) 4 mm tipped electrodes and locally assembled RF energy delivery system. Results: The procedure was successful in 27/30 (90%) patients using RF energy, while three patients required DC energy to achieve successful AV junction ablation. General anaesthesia was required in nine patients, six of whom required this for cardioversion to sinus rhythm so that an adequate His Bundle spike could be recorded and three for DC ablation. Dual chamber permanent pacemakers with automatic mode switching were implanted in four patients who had paroxysmal atrial fibrillation or flutter and the remainder had ventricular rate responsive pacemakers. Conclusions: In patients with drug refractory paroxysmal atrial fibrillation and flutter and in patients with established atrial fibrillation where control of the ventricular rate is difficult, catheter ablation of the AV junction using RF energy is a safe and effective procedure with a high success rate.