Conduction System Pacing Today and Tomorrow

Figures

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  Figure 1. Paced QRS morphology in a patient with a dual-chamber PM and an LBBAP lead. V1 exhibits an R’, R-wave peak time in V6 is ~70 ms, the V1–V6 interpeak interval is ~35 ms and paced QRS duration is ~120 ms.

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  Figure 2. Computed tomography (CT) images of a patient with AV block after transcatheter aortic valve replacement and consecutive dual-chamber PM implantation with a ventricular lead in LBBAP position. (A) The deep septal implantation site of the CSP lead in a short-axis projection. (B) The basal implantation site in the proximal left bundle in a reconstruction. The resulting ECG is shown in Figure 1.

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  Figure 3. ECG leads V1 and V6 during LBBAP lead implantation. Continuous unipolar pacing is performed from the lead’s tip. ① A wide QRS reflecting right ventricular septal pacing with a notch near the nadir of the QRS (one of the criteria for a suitable starting position for lead drilling). ② During the drilling process, this notch starts to move towards the end of the QRS in V1 and the QRS duration is shortened (deep septal pacing). ③ Finally, an r’ appears in V1 and the QRS suddenly shortens again significantly, indicating CSP capture.

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  Figure 4. 12-lead ECG from a patient, who underwent LBBAP lead implantation. The unipolar electrogram (CSPuni) shows a left bundle branch potential during intrinsic rhythm, which is indicative of successful positioning of the lead in the specific conduction system (arrow).

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  Figure 5. Implantation of a leadless CSP PM in a domestic pig. The steerable implantation catheter (asterisk) allows positioning the stimulation electrode towards the interventricular septum (solid arrow). The main body of the leadless PM is implanted in an apical position (dotted arrow). The corresponding ECG with a simulated QRS duration of <100 ms is shown on the right.