Characteristics and proposed meaning of intrinsic intracardiac electrogram morphology observed during the left bundle branch pacing procedure: A case report

Figures

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  Figure 1. Morphologies of intrinsic intracardiac electrogram (EGM) during lead penetration through right ventricular septum (RVS) to left ventricular septum (LVS) and the following schematic representation of the position of the lead. All of the intrinsic intracardiac EGM that occurred during the lead screwing procedure were presented in picture and the associated occurrence time was marked. Four patterns of morphologies were shown as pattern A, pattern B, pattern C, and pattern D. LB Po = left bundle branch potential; LBB = left bundle branch; LV = left ventricular; RV = right ventricular; VS = ventricular septum.

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  Figure 2. Morphologies of the paced electrocardiogram (ECG) and electrogram (EGM) in patterns A–D. Pattern A: Precordial transition of paced ECG between V2 and V3 and classic W pattern with a notch in the middle of the QRS in lead V1. Pattern B: Transition zone changed to V2. Pattern C: Transition zone changed to between V1 and V2 and notch shifted rightward without a late R wave in V1. Pattern D: Transition zone changed to lead V1, rSR pattern was observed just after the appearance of late R wave in V1, S wave was present in lead V6, the time from stimulus to R-wave peak time in V5 suddenly shortened from 102 ms to 67 ms in 91 seconds, and a distinct isoelectric interval in EGM was observed. LB Po = left bundle branch potential.