CATHETER ABLATION OF THE ATRIOVENTRICULAR NODE USING RADIOFREQUENCY ENERGY

Background: Catheter ablation of the atrioventricular (AV) junction us ing stored direct current (DC) energy from a standard DC Cardioverter defibrillator was first reported in 1982. Since then many patients hav e been treated using this procedure for refractory supraventricular ar rhythmias, usually atrial fibrillation and flutter. Undesirable therma l effects such as barotrauma and arcing are largely responsible for co mplications associated with the use of DC energy. This report details our experience of catheter ablation of the AV junction using radiofreq uency (RF) energy in a series of 30 consecutive patients. Methods: RF ablations were performed using steerable Mansfield (Webster Laboratori es) 4 mm tipped electrodes and locally assembled RF energy delivery sy stem. Results: The procedure was successful in 27/30 (90%) patients us ing RF energy, while three patients required DC energy to achieve succ essful 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 D C ablation. Dual chamber permanent pacemakers with automatic mode swit ching were implanted in four patients who had paroxysmal atrial fibril lation or flutter and the remainder had ventricular rate responsive pa cemakers. Conclusions: In patients with drug refractory paroxysmal atr ial fibrillation and flutter and in patients with established atrial f ibrillation where control of the ventricular rate is difficult, cathet er ablation of the AV junction using RF energy is a safe and effective procedure with a high success rate.