A Novel Mapping Strategy of Repetitive Patterns in Consecutive Recordings to Localize Atrial Fibrillation Sources: an In-Silico Study.

In some patients with persistent atrial fibrillation (AF), localized functional mechanisms may sustain AF and thus represent ablation targets. We propose a novel mapping strategy to locate AF sources by combining repetitive patterns from consecutive high-density mapping recordings. The algorithm moves the catheter iteratively upstream of the main repetitive conduction direction to identify an AF source either by direct classification of local activation patterns or by encircling it. We tested the performance and robustness of this approach in two groups of detailed AF simulations, without and with severe structural remodeling ( $N=20$ per group, 20 starting positions per simulation), using a $4\times 4$ grid mapping catheter (3mm spacing). Structural remodeling led to more simultaneous sources (median [IQR], 2 [1; 3] vs 3 [2; 5], $p < 0.001)$ that meandered in larger areas (127.5 [82.0; 216.0] vs 188.0 [121.2; 305.5] mm 2 , $p < 0.05$ . The mapping approach localized a source in 6 [4; 9] vs. 5 [5; 8] steps for the groups without and with structural remodeling ( $p < 0.001$ ), with an accuracy of 11 [7; 16] vs 9 [6; 14] mm ( $p=0.046$ ). Sources were localized by encircling in 62.6% vs. 41.4% of the detection in both groups, respectively. The proposed mapping strategy detected AF sources accurately within a few steps, even in complex AF substrates, with a substantial contribution of encircling to detect sources.