Deep septal deployment of a thin, lumenless pacing lead: a translational cadaver simulation study

Abstract

Aims The recently introduced technique of direct transseptal pacing of the left bundle branch is poorly characterized with many questions with regard to the optimal implantation strategy and safety concerns largely left unanswered. We developed a cadaver model for deep septal lead deployment in order to investigate the depth of penetration in relation to lead behaviour, lead tip position, and the number of rotations. Methods and results Five fresh human hearts and five lumenless, 4.1-Fr pacing leads were used for deep septal deployment simulations. The leads were positioned with the use of a dedicated delivery sheath and screwed into the interventricular septum at several sites progressively more distal from the atrioventricular ring with a predetermined number of lead rotations. During each lead deployment, the depth of tip penetration was measured and the lead behaviour was noted. Four distinct lead behaviours were observed: (i) helix only penetration, no matter how many rotations were performed, due to the ‘endocardial entanglement effect’ (43.1% cases) or (ii) ‘endocardial barrier effect’ (19.6% cases), (iii) shallow/moderate penetration, with ensuing ‘drill effect’ when more rotations were added (9.8% cases), and (iv) deep progressive penetration with each additional rotation, occurring when the ‘screwdriver effect’ was present (27.4% cases, including three septal perforations). These different lead behaviours seemed to be determined by the lead position—mainly the strength of the initial endocardial layer—and the number of fully transmitted rotations. Conclusion New insights into deep septal lead deployment technique were gained with regard to safe and successful implantation.

Programmed deep septal stimulation: A novel maneuver for the diagnosis of left bundle branch capture during permanent pacing

“…We aimed at any basal to mid‐interventricular septal site where proper deep septal lead deployment was possible. Lead behaviors during deep septal deployment, characterized by us elsewhere, 10 were used to guide lead positioning and fixation. The area located approximately 2 to 3 cm apically from the distal HB site was targeted; preferentially characterized by paced QRS morphology in V1 showing notch near the S wave nadir (“W” morphology) and/or being slightly narrower than the paced QRS from neighboring sites and with normal axis in the frontal plane (R in lead I, Rs in lead II, and rS in lead III).…”

“…We aimed to obtain paced QRS with an r′ deflection in lead V1, record LBB potential and/or observe evident QRS narrowing as compared with the initial right ventricular septal paced QRS. If after 5 to 8 lead turns, a typical progressive change of paced QRS morphology was not observed or early strong counterclockwise torque build‐up in the lead was present, 10 the lead was repositioned. This implantation technique was similar not only to the recently described approach to LBB pacing by Huang et al 4 but also to the left septal pacing method developed by Mafi‐Rad at al 5 …”

Fixation beats – a novel marker for reaching the left bundle branch area during deep septal lead implantation

“…When after the initial 5 rotations the torque created in the lead was not transmitted but remained in the lead body, the 'entanglement response' or fibrous site was suspected and the implantation site was changed. 7 When after the initial 5 rotations or after the subsequently added rotations there was no progressive change in paced QRS morphology, the 'drill effect' was suspected and either more All rights reserved. No reuse allowed without permission.…”

“…LBB capture was diagnosed when either direct proof was obtained with differential pacing output or programmed / burst stimulation or one of the indirect, arbitrary criteria was present (time to R wave peak in V5/V6 < 85 ms, QRS ≤ 120 ms, or LBB potential on the 3830 lead electrogram). 2,[6][7][8]…”

“…When after the initial 5 rotations the torque created in the lead was not transmitted but remained in the lead body, the 'entanglement response' or fibrous site was suspected and the implantation site was changed. 7 When after the initial 5 rotations or after the subsequently added rotations there was no progressive change in paced QRS morphology, the 'drill effect' was suspected and either more forward pressure was attempted, sheath angle/torque was modified to offer better support for the lead or the implantation site was changed. 7 In the prospective, fixation-beat-guided, phase of the study the implantation technique was modified.…”