Abstract Body (Do not enter title and authors here): Introduction: The mechanisms underlying the persistence of atrial fibrillation (AF) are still debated. Studies in animal and human cardiac bench top models suggest that different mapping techniques influence the detection of localized sources or self-sustaining, transient wavelets in AF. Despite this, no human studies have examined the influence of a local versus global mapping approach on the detection of these sources simultaneously in the same patient.

Objective: We hypothesize that local and global mapping of AF offer different spatiotemporal resolutions that influence the nature of sustaining mechanisms but not their location in the chamber. This will be particularly evident for rotational sources.

Methods: 16 patients who underwent catheter ablation for AF, atrial flutter (AFL), or premature atrial contractions (PACs) were studied. All patients underwent electroanatomic mapping of the left and right atria with both local and global approaches. Anatomical locations were subdivided into different regions (Figure 1A, 1B). Mechanisms were classified as focal, rotational, or localized irregular activation (LIA) using mapping algorithms. Analyses were done using Chi-squared tests.

Results: A total of 40 AF, 12 AFL, and 4 PAC simultaneous electroanatomic maps were obtained. Both local and global mappings identified an AF source (n=52) within close anatomical proximity 86.5% of the time (p<0.001). However, mechanisms differed between AF sources identified with different views (34.6% same, 65.4% different, p=0.03) (Figure 1C). These different mechanisms were 47.1% rotational and 50% LIA on global maps (n=34, p<0.001) and 94.7% focal on local maps (n=19, p<0.001) (Figure 1D). AF sources with the same activation pattern across different scales were mostly identified as focal (94.4%, p<0.001). In contrast, AFL and PACs shared both location (100%, p=0.005) and mechanism (87.5%, p=0.03) across local and global maps.

Conclusion: Local and global maps offer different spatiotemporal resolutions that influence how a mechanism of a source is portrayed, and hence ablation strategy. This has a greater impact on rotational sources in AF, and may explain the divergent results in pre-clinical and clinical AF mapping studies.