How to perform pulmonary vein isolation.

The advent of technology for the delivery of radiofrequency energy via electrode catheters, in the late 1980s, led to the perfection of techniques for the ablation of accessory pathways and classical flutter [1e4]. This has been so successful that these substrates for arrhythmia are rarely seen in the Western world. Two major arrhythmias, however, still remain to be conquereddatrial fibrillation and ventricular tachycardia/fibrillation. The occurrence of atrial fibrillation (AF) seems to be dependent on a number of factors [5]. In most situations there is some form of underlying atrial substrate, which is usually the presence of intraatrial conduction delay. In addition, initiating factors for AF are required and the commonest of these appear to be atrial ectopic beats [6]. The major sources of these ectopic beats appear to be the pulmonary veins [7], although extrapulmonary vein sources are being increasingly reported [8,9]. Numerous recent studies suggest that AF may be treated by the techniques based on ablation within