Techniques for the provocation, localization, and ablation of non-pulmonary vein triggers for atrial fibrillation

The end point of current catheter-based ablation approaches for the treatment of atrial fibrillation (AF) is the elimination of all the possible triggers with the least amount of ablation necessary. Once all the triggers have been eliminated, the incremental value of any additional lesion sets remains to be proven. Pulmonary vein (PV) isolation is the cornerstone of catheter ablation approaches for eliminating AF triggers. However, up to 11% of patients demonstrate reproducible sustained AF initiation from non-PV foci. In these patients, triggers can typically be elicited using standardized induction protocols, which include cardioversion of spontaneous and/or induced AF and infusion of high-dose isoproterenol. Non-PV triggers typically arise from discrete anatomical structures that include the mitral and tricuspid periannular regions, the crista terminalis and Eustachian ridge, the interatrial septum, the left atrial (LA) posterior wall, the left atrial appendage (LAA), and other thoracic veins such as the superior vena cava, the coronary sinus, and the ligament of Marshall. Localization of non-PV foci involves a detailed analysis of specific intra-atrial activation sequences using multipolar catheters in standard atrial locations coupled with information from the surface electrocardiogram P wave when possible. Multipolar catheters positioned along the coronary sinus and crista terminalis/superior vena cava region together with direct recordings from the right and left PVs allow a quick localization of non-PV foci. Elimination of non-PV triggers by means of focal ablation at the site of origin or isolation of arrhythmogenic structures (eg, LA posterior wall or superior vena cava) has been associated with improved arrhythmia-free survival.