Combined contact force and local impedance dynamics during repeat atrial fibrillation catheter ablation

Figures

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  FIGURE 1. (A) Representative CF and LI raw as well as time-smoothed averaged recordings in a single patient during ablation are displayed. High baseline LI (dark blue) predicted increased ∆LI, while lower baseline LI (light blue) resulted in low δLI despite similar energy output of 30 W and adequate CF levels ≥8 g. (B) Baseline LI correlated better with ∆LI (upper panel) compared to the ∆LI% (lower panel). CF, contact force; LI, local impedance; ∆LI, absolute local impedance drop; ∆LI%, relative local impedance drop.

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  FIGURE 2. (A) Representative CF and LI raw as well as time-smoothed averaged recordings in a single patient during ablation are displayed. In regions of similar baseline LI, high constant CF (blue curve) resulted in a rapid δLI after approximately 4 s, whereas intermittent decreases of CF to 0 g due to inspiration (violet) went along with LI increases reflecting transient catheter-tissue contact loss with overall similar δLI. Continuously low CF (red) resulted in a reduced ∆LI. (B) Correlation of minimum/maximum/mean CF during ablation and force-time integral with ∆LI (upper panel) and ∆LI% (lower panel). (C) A mean CF < 8 g was concomitant with a reduced LI drop, whereas increases beyond 8 g did not further increase the LI drop. **p ≤ 0.01; ****p ≤ 0.0001. For abbreviations see Figure 1.

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  FIGURE 3. (A) Correlation analysis of baseline CF to LI (upper panel) and mean CF to the ∆LI (lower panel) is shown. (B) Baseline LI and ∆LI during ablation are displayed depending on local bipolar voltage and applied CF classified by the estimated mean CF cut-off of 8 g. (C) Correlation analysis of mean CF to ∆LI depending on underlying baseline LI terciles. *p ≤ 0.05; ***p ≤ 0.001. For abbreviations see Figure 1.

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  FIGURE 4. Predictors of a local impedance drop >20 Ω during ablation. During receiver operating characteristics analysis, combined mean CF and baseline LI showed the highest area under the receiver operating characteristics curve for predicting a >20 Ω. AUC, area under curve. For further abbreviations see Figure 1.