Pace mapping options with the lumen-less pacing lead
In the early development of LBBAP, Jastrzębski and others, using the lumen-less Medtronic 3830 lead, proposed to continuously pace mapping during LBB implant by keeping the crocodile connector onto the lead CP.[10–12] Unfortunately, given the lack of commercially available revolving connectors for the distal pin, practical application of this technique was limited by the unstable connection and more importantly by the significant risk of fracture between the distal pin and the inner conducting wire. Accordingly, further practical development focused on the recognition of “irritative” PVCs generated during the transseptal screwing of the LBB lead. Ponnusamy et al. proposed monitoring of the change in PVC during lead positioning (dubbed by the authors as “template beats”). In their study, only two-thirds of the patients demonstrated PVCs during rapid lead deployment. Moreover, their occurrence was inconstant and unpredictable.[5,13] Similarly, Jastrzębski et al. proposed instead of interrupted pace mapping after each set of lead rotations, to continue the initial lead rotations until typical relatively narrow RBB PVCs (called “fixation beats”) appears.[11] Although very specific, “fixation beats” appear only when the lead has already reached the LBB area and indicates thus that lead rotations should be immediately stopped to prevent LV perforation. As recognized by de authors, this technique can be challenging (especially in RBBB patients) and needs a strict monitoring of their occurrence to avoid perforation.