Guidance on left bundle branch pacing using continuous pacing technique and changes in lead V1 characteristics under real-time monitoring

Figures

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  Figure 1. The four pacing modalities of the implantation. (A) Body surface 12-lead ECG and LBB potential in both LVSP and NS-LBBP (Low output) phases. Two of the nodes are adjacent to heartbeats. In the deeper septum and LV endocardium, when the stim-V6 RWPT is abruptly shortened, the pacing modality changes from LVSP to NS-LBBP. (B) Body surface 12-lead ECG and LBB potential in NS-LBBP (Lower output) and S-LBBP phases. RWPT-V6 is 60 ms at NS-LBBP (lower output) and 60 ms at S-LBBP. Two of the nodes are adjacent to heartbeats. At the LBB, the pacing modality transitions from NSLBBP to SLBBP when a discrete component appears on the intracardiac electrogram with fixed stim-V6RWPT.

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  Figure 2. V1 morphology for the four key nodes. (A) Graphical and quantitative statistics of all morphology for the four nodes, with the most common morphology marked in red. (B) Proportion of V1 morphology at the LVSP stage. (C) Proportion of V1 morphology at the NS-LBBP (Low output) stage. (D) Proportion of V1 morphology at the NS-LBBP (Lower output) stage. (E) Proportion of V1 morphology at the S—LBBP stage.

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  Figure 3. IEGM and ECG in the pacing and sense-only mode at the final test. Where A1-B1, A2-B2, A3-B3, A4-B4 are the same patient. TIP (-) in part B shows the ECG and IEGM in unipolar sense-only mode at the TIP end, RING (+) shows the ECG and IEGM in unipolar sense-only mode at the RING end, and TIP (-) RING (+) is the ECG and IEGM in bipolar sense-only mode. Part A (A1, A2, A3, A4) shows the ECG and IEGM in the pacing mode, including the TIP end on the left and the RING end on the right, as well as the bipolar mode. The ECG and IEGM in the TIP end is indicated by the blue bar, and the red bar indicates the ECG and IEGM in the RING end.

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  Figure 4. Schematic diagram of the conduction of electrical activity about the four nodes. The arrows indicate the direction of electrical activity conduction, red arrows are electrical activity conduction between cardiomyocytes and green arrows are electrical activity conduction of conduction bundles. A1, A2, A3, A4 and B1, B2, B3, B4 are ECG patterns of LBB, V1, V6 in two patients. A1: RWPT(ms) of V1 and V6 in LVSP phase. A2: RWPT(ms) of V1 and V6 in NS-LBBP (Low output) phase. A3: RWPT(ms) of V1 and V6 in NS-LBBP (lower output) phase. A4: RWPT(ms) of V1 and V6 in S-LBBP phase. B1: S- and R-wave amplitudes(mv) in lead V1 in LVSP phase. B2: Amplitude(mv) of S and R waves of V1 leads in NS-LBBP (Low output) stage. B3: Amplitude(mv) of S and R waves of V1 leads in NS-LBBP (Lower output) stage. B4: Amplitude(mv) of S and R waves of V1 leads in S-LBBP stage.