Pulmonary vein paced activation sequence mapping: Comparison with activation sequences during onset of focal atrial fibrillation

Introduction: Atrial fibrillation (AF) may originate from a single focus, with the vast majority observed within the pulmonary veins. To facilitate mapping, we hypothesized that there would be a characteristic right atrial endocardial activation sequence pattern associated with pacing and spontaneous focal activity from each of the four pulmonary veins. Methods and Results: In 10 patients with focal AF, a standardized set of catheters was positioned in the right atrium. These included a 20-pole catheter along the crista terminalis, a decapolar catheter in the coronary sinus (CS), and a His-bundle electrode. Pacing (700 and 300 msec) was performed with a mapping catheter from each of the four pulmonary veins. Activation sequence maps were created by measurement of activation times to each of the recording bipoles with the proximal CS bipole as the arbitrary reference point. Similar maps were constructed for the activation sequence of the pulmonary vein ectopic that initiated AF. There was a characteristic right atrial activation map created by pacing each pulmonary vein that corresponded closely with the map from the same pulmonary vein during initiation of focal AF. The pulmonary vein of origin could be distinguished on the basis of this characteristic pattern and some stereotypic observations. CS activation occurred proximal to distal for right pulmonary veins and distal to proximal for left pulmonary veins. Significant differences in activation timing between the CS and crista terminalis differentiated upper from lower pulmonary veins. Conclusion: There is a characteristic right atrial activation map for activity arising from each of the four pulmonary veins that corresponded closely with the map from the same pulmonary vein during initiation of focal AF. These findings may facilitate mapping and ablation of focal AF.