Evaluating Pulmonary Vein Isolation

Pulmonary vein isolation is the electrophysiological endpoint of complete conduction block at the level of the veno-atrial junction and must be explicitly distinguished from encircling PV ablation which frequently does not result in isolation. The prerequisites for successful PV isolation include a knowledge of the individual anatomy of the PVs and the left atrium, appropriate positioning of circular mapping catheters, and a knowledge of the electrophysiology of PV activation, in addition to effective ablation tools. Excessive ablation, and possibly complications, can be avoided by the recognition of non-PV myocardial contributions to electrograms recorded from within the PVs. The posterior wall of the left atrial appendage contributes far-field electrograms to recordings from all or nearly all left superior PVs, the low anterior left atrium to 80% of left inferior PV recordings and the superior vena cava to 23% of right superior PV recordings. Recognition of these far-field components is feasible and accurate in sinus rhythm as well as during ongoing atrial fibrillation. Finally, the creation of temporally stable PV isolation remains a currently unsolved problem although prolonged post isolation surveillance, may be helpful.