Curative catheter ablation of atrial fibrillation (AF) began with the recognition of ectopic impulses triggering AF, originating dominantly from the pulmonary veins (PV). Electrical isolation of the PV from the LA was proposed to eliminate these triggers from the PV and is now performed with the aid of a circumferential PV mapping (lasso) catheter. In addition to the initiating role of the PV, this structure is also critical as a substrate maintaining AF.1 The importance of PV isolation in AF ablative therapy therefore remains unchanged since the development of this technique whether it is for paroxysmal, persistent or permanent AF.