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.