Insights From Simultaneous Left and Right Atrial Septal Mapping in Patients With Persistent Atrial Fibrillation

BACKGROUND The interatrial septum (IAS) is thought to be involved in the mechanism of persistent atrial fibrillation (PeAF). Simultaneous contact mapping of both sides of the IAS has not been performed previously. OBJECTIVES The purpose of this study was to describe wave front (WF) activation patterns and extent of left and right atrial septat electrical dissociation in patients with PeAF. METHODS Simultaneous mapping of both atrial septat surfaces using 2 high-density grid catheters was performed. Filtered etectrograms of continuous atrial fibrillation, sinus rhythm (SR), and atrial pacing recordings were exported to MATLAB for off-tine phase/activation analysis, and activation patterns on paired surfaces were analyzed. WF activation patterns between the 2 grids were evaluated to determine whether activation WFs were associated or dissociated. RESULTS Eight patients with PeAF undergoing catheter ablation were included. Complete dissociation of WF activation patterns between the 2 sides of the septum existed throughout the mapping period with no 2 consecutive WF activation patterns matching. Single linear WFs were the most prevalent activation pattern on both septat grids. No focal breakthroughs were seen. Transient rotational activity was seen in 10% of phase activations. During SR and atrial pacing, both grids appeared to be activated independent of each other with no evidence of contrataterat conduction across the 2 grids. CONCLUSIONS Simultaneous biatrial septat mapping of human PeAF, SR, and atrial pacing shows complete WF dissociation between the left and right IAS with no evidence of trans-septat conduction, indicating that the 2 sides function as electrically discrete structures. No stable septat drivers were observed. These findings may have implications for mapping and ablation of PeAF. (C) 2022 by the American College of Cardiology Foundation.

Automated summary

This study demonstrated complete wave front dissociation between the left and right interatrial septum in patients with persistent atrial fibrillation. The findings suggest that the two sides of the septum function as electrically discrete structures and may have implications for mapping and ablation of persistent atrial fibrillation.