Fig. 5
Evaluation of electrogram changes after PFA. (a) Schematic drawing of unipolar and bipolar iEGM recording generation. (b) Calculation of the current of injury (COI) parameter from unipolar iEGM signals. Blue circles: baseline value measured before the QRS. Red crosses: the start and the end of the area under the curve (AUC - shaded area) window, based on criteria described in the methods. The COI parameter (black arrow) was defined as the AUC divided by the AUC window width. (c) Examples of concrete signals recorded at two different ventricular sites treated with two different doses of PFA and shown for three different time points (pre-ablation, 30 s post-ablation and 3.5 min post-ablation). (c.1) Example 1: a lower dose (1300 V, 4 trains); (c.2) Example 2: a higher dose (1500 V, 8 trains). (d) and (e) Comparison of changes in peak-to-peak amplitude of bipolar iEGMs (bandwidth: 30–500 Hz). (d) Absolute values at three different time points (pre-ablation, 30 s post-ablation and 3.5 min post-ablation) grouped by the dose delivered. (e) Post-ablation values normalized to the pre-ablation values. A linear mixed effects (LME) model was used to compare doses and post-treatment times, taking the form: relative PP values ~ Time + Dose + (1|PigID/lesion) (*p < 0.05), where the dose was either the voltage or the number of pulses. (f) and (g): Comparison of changes in COI of unipolar iEGMs (bandwidth: 0.5–500 Hz). (f) Absolute values at three different time points (pre-ablation, 30 s post-ablation and 3.5 min post-ablation) grouped by the dose delivered. LME model was used to compare doses and post-treatment times, taking the form: COI ~ Time + Dose + (1|PigID/lesion) (*p < 0.05), where the dose was either the voltage or the number of pulses. (g) Values of COI recorded 3.5 min post-ablation normalized to COI values recorded 30 s post-ablation. LME model was used to compare doses, taking the form: relative COI ~ Dose + (1|PigID) (*p < 0.05, **p < 0.01), where the dose was either the voltage or the number of pulses.
