Granger causality connectivity analysis of persistent atrial fibrillation dynamics reveals posterior wall mechanistic insights

Figures

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  Figure 1. An overview of Granger causality analysis applied to simultaneous electroanatomic noncontact mapping.

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  Figure 2. Three representative examples showing left atrial Granger causality connectivity maps. There is no significant difference in connectivity by region or before/after pulmonary vein isolation. Top panels show posterior view; bottom panels show an anterior view. The pulmonary veins are depicted in gray, the posterior wall is depicted in red, and the rest of the left atrium is blue.

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  Figure 3. CPI was computed before and after pulmonary vein isolation for the left atrium as a whole and by region. There were no significant differences in CPI by region or before/after PVI. CPI = causality pairing index; PVI = pulmonary vein isolation; PW = posterior wall.

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  Figure 4. Mean DD is a measure of conduction heterogeneity. Mean DD was significantly lower in PW than the rest of the left atrium before pulmonary vein isolation, but not after ablation. Overall, mean DD in the PW significantly increased after pulmonary vein isolation; however, there were a minority of cases where the opposite trend is observed. DD = directional dispersion; PW = posterior wall.

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  Figure 5. Representative examples showing Granger causality connectivity maps and directional dispersion heat maps. A: Directional dispersion in the posterior wall (PW) increases after pulmonary vein isolation. B: Directional dispersion in the PW decreases after pulmonary vein isolation. The pulmonary veins are depicted in gray; the PW is depicted in red, and the rest of the left atrium is blue.

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  Figure 6. Granger causality connectivity maps were used to compute net outflow from PW. Positive net outflow indicates the PW was a net source, whereas negative indicates a net sink. Overall, there was no significant change in outflow after pulmonary vein isolation. After pulmonary vein isolation, in the majority the PW was a net sink, but was a source in a minority of cases. PW = posterior wall.

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  Figure 7. Representative examples showing Granger causality connectivity maps and posterior wall outflow after pulmonary vein isolation. In the inflow/outflow maps, blue arrows indicate inflow into the posterior wall and red arrows indicate outflow. A: Example of a net sink. B: Example of a new source. The pulmonary veins are depicted in gray, the posterior wall is depicted in red, and the rest of the left atrium is blue.