Methods to identify the pulmonary vein ostium

In summary, several methods for defining the ostium of the pulmonary vein are available. Currently there is no known gold standard, including direct anatomic examination of the left atrium and attached veins. Identifying the pulmonary vein ostium is important for two reasons. The first is to avoid pulmonary vein stenosis. In this regard, angiography, which tends to underestimate the ostium (placing it back in the left atrium), and intracardiac ultrasound are commonly used and are effective. Second, based on previous reports, the arrhythmogenic transition zone between the left atrium and pulmonary vein may occur at the ostium. This electrical ostium or site of delay can be determined with relatively straightforward pacing maneuvers. Additional studies are needed to show which imaging technique, electrogram criteria, approach to ablation, or pacing maneuver gives the best result in reducing the incidence of pulmonary vein stenosis and maintaining acceptable efficacy in controlling atrial fibrillation. If experimental methods of ablation, for example, cryoablation at the pulmonary vein ostium, are shown to not produce pulmonary vein stenosis but maintain efficacy, then possibly less attention to determining this anatomic site will be required.