Right Pulmonary Vein Potentials Recorded from the Posterior Right Atrial Endocardium: Human Case Report and Validation in a Porcine Model

A 33-year-old woman underwent successful catheter ablation of an atrial tachycardia emanating from deep within a large right superior pulmonary vein (RSPV). A previous ablation attempt in this patient had failed, during which radiofrequency energy applications were made to the posterior right atrium only. The mistaken impression of a right atrial source for this tachycardia was due to RSPV potentials that were recorded during mapping in a region of the posterior right atrium contiguous to the vein ("contiguity region"). To further evaluate this, we performed activation mapping and radiofrequency ablation in atria of healthy pigs. Similar to the reported case, "biatrial" potentials were recorded from both left and right aspects of the contiguity region. Radiofrequency energy application altered only the potential emanating from the atrium in which the lesion was applied. Histologic analysis confirmed that the lesion was limited to this atrium. It is concluded that, due to their proximity, electrical activity in the RSPV may be recorded from certain areas of the posterior right atrium, and vice versa. In the reported case of left atrial tachycardia, this led to the mistaken impression of right atrial tachycardia.