Premapping Commanded Electrogram Parameters and 3-Month Atrial Pacing Threshold After Atrial Leadless Pacemaker Implantation

Figures

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  Figure 1. Measurement of premapping commanded electrogram (cEGM) parameters. A: Definitions of cEGM amplitude, current of injury, cEGM duration, and R-wave first derivative of voltage over time measured from premapping commanded electrograms. Measurements were evaluated at premap, postfixation (tether mode), and postdeployment.

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  Figure 2. Temporal changes in electrical parameters according to 3-month atrial pacing threshold. Line graphs show impedance, sensing amplitude, and atrial PCT at premapping, postfixation, postdeployment, postimplant day 1, 1 month, and 3 months. Data are presented as median and interquartile range. PCT = pacing capture threshold.

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  Figure 3. Assessment of commanded electrogram parameters: a conceptual visualization framework. A: Grid-based conceptual schematic for visualizing the R-wave upstroke velocity (dV/dt-R) on a standard programmer display. In our exploratory analysis, steeper upstrokes (illustrated by the green region, with dV/dt-R values of approximately ≥140 V/s shown as a hypothesis-generating reference value) tended to occur in patients with very low chronic PCTs, whereas shallower upstrokes (red region, approximately ≤80 V/s) tended to occur in patients with elevated chronic PCT. The numerical values shown are illustrative reference values for visualization only and are not validated procedural or clinical cutoffs; this panel is intended as a conceptual framework and is not intended to guide procedural or clinical decision making. B: Representative premapping commanded electrograms shown as illustrative examples grouped by chronic outcome. Tracings from patients with very low chronic PCT included a high-amplitude signal (2.3 mV) with a steep upstroke (dV/dt-R 178 V/s) and a preserved-amplitude signal (1.3 mV) with an adequate upstroke (dV/dt-R 123 V/s). Tracings from patients with elevated chronic PCT…