Local catheter impedance drop during pulmonary vein isolation predicts acute conduction block in patients with paroxysmal atrial fibrillation: initial results of the LOCALIZE clinical trial

Figures

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  Figure 1. Representative example of a left atrial electroanatomic map with anatomical segments defined (n = 16). Segment borders are defined with light blue tags and segment centres with purple tags. A, anterior; I, inferior; L, left; P, posterior; R, right; S, superior.

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  Figure 2. Representative example of the local impedance trace and median local impedance drop calculation per anatomical segment. (A) Seven consecutive radiofrequency ablations (orange overlay and white arrows) with raw (white) and filtered (yellow) local impedance traces displayed. (B) Activation map identified a gap in the right posterior segment (grey tag, white asterisk) after the 20-min waiting period. Tag colours: black—RF ablation, light blue—segment border, and purple—segment centre. RF, radiofrequency.

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  Figure 3. Relationship between LI drop and acute block after first-pass encirclement. (A) Median LI drop in acutely blocked (n = 659) and gap (n = 133) segments (left) and corresponding ROC curve analysis (right). (B) Median LI drop in acutely blocked (n = 372) and gap (n = 44) segments with inter-lesion distance ≤6 mm and corresponding ROC curve analysis (right). Highlighted threshold values in the box-and-whisker plots (10 Ω: green, 15 Ω: pink, 20 Ω: blue, and calculated optimal: black dashed) are displayed as coloured points in the ROC curve plots. LI, local impedance; ROC, receiver operating characteristic.

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  Figure 4. Relationship between LI drop and regional acute block after first-pass encirclement. (A) Median LI drop in anterior/superior acutely blocked (n = 172) and gap (n = 29) segments with inter-lesion distance ≤6 mm (Left) and corresponding ROC curve analysis (right). (B) Median LI drop in posterior/inferior acutely blocked (n = 200) and gap (n = 15) segments with inter-lesion distance ≤6 mm (left) and corresponding ROC curve analysis (right). Highlighted threshold values in the box-and-whisker plots (10 Ω: green, 15 Ω: pink, 20 Ω: blue, and calculated optimum: black dashed) are displayed as coloured points in the ROC curve plots. LI, local impedance; ROC, receiver operating characteristic.

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  Figure 5. Scatter plot with lines of best fit demonstrating the correlations between starting LI and LI drop (blue points/line) and between starting generator impedance and generator impedance drop (orange points/line). LI, local impedance.