Implant, assessment, and management of conduction system pacing

Figures

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  Figure 1. His anatomical variations and the effect on pacing response of His bundle pacing with varying pacing outputs. See text for further explanation.

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  Figure 2. His-bundle electrogram mapping approach with the 12-lead ECG and unipolar electrogram of the tip of the His-bundle lead showing a small atrial signal (A), the His-bundle potential (H) and a large ventricular signal (V).

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  Figure 3. Hallmarks of selective and non-selective His bundle pacing.

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  Figure 4. When viewed from the right atrial cavity (A), the fibrous membranous septum forms the apex of the triangle of Koch (transillumination). The hinge of the septal leaflet of the tricuspid valve provides the dividing line between the atrio-ventricular and interventricular components of the membranous septum. (B) The left posterior oblique view shows the transilluminated membranous septum located inferior to the interleaflet triangle between the right (R) and non-coronary (N) sinus of the aortic valve. Note that we have highlighted in dark colour the limits of the endocardial position of the left bundle branch (LBB) of His and its three fascicles, the left anterior (1), the left septal or middle (2), and the left posterior (3). LPO = left posterior oblique; RAO = right anterior oblique. With permission from Cabrera et al.25

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  Figure 5. Demonstration of non-selective to selective left bundle branch capture while checking unipolar threshold. Note the distinct local electrogram on the pacing lead after the pacing stimulus with change in QRS morphology from qR to rSR pattern. His d and His p, His bundle electrogram distal and proximal; LBP, LB pacing lead; LB U, LB pacing lead unipolar electrogram; RVA, right ventricle electrogram. With permission from Ponnusamy et al.33

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  Figure 6. Algorithm for confirming conduction system capture with left bundle branch area pacing. Some of the steps may be skipped according to operator preference, experience or feasibility to perform particular measurements/manoeuvres. DSP, deep septal pacing; IVCD, intra-ventricular conduction delay; LBBAP, left bundle branch area pacing; LBBB, left bundle branch block; ns-LBBP, non-selective left bundle branch pacing; RBBB, right bundle branch block; RBBP, right bundle branch pacing; RWPT, R-wave peak time; s-LBBP, selective left bundle branch pacing. With permission from Burri et al.38

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  Figure 7. ECGs illustrating left bundle branch pacing (LBBP), left fascicular pacing (LFP) and left ventricular septal pacing (LVSP). QRS axis results both from conduction system capture as well as surrounding myocardial capture. Note the similarity in morphology between left bundle branch pacing and left left anterior fascicular pacing, which may be distinguished by the potential to QRS interval (if present), and anatomic lead position. Potential to QRS intervals recorded in intrinsic rhythm by the pacing lead are also shown for left bundle branch pacing and left fascicular pacing. Sweep speed of 25 mm/s for the paced QRS tracings and 100 mm/s for those in intrinsic rhythm. With permission from Burri et al.38