Key result
Programmed deep septal pacing successfully diagnosed left bundle branch capture in 79.7% of patients by differentiating the refractory periods of the LBB and septal myocardium.
Why the study?
Confirming left bundle branch capture during permanent deep septal pacing is important, and investigators hypothesized that differing refractory periods between myocardium and left bundle branch could enable differentiation via programmed extra-stimuli.
Does programmed deep septal pacing using an extra-stimulus technique differentiate LBB capture from septal myocardial capture in patients undergoing pacemaker implantation?
Observational (n=143)
Does programmed deep septal pacing using an extra-stimulus technique differentiate LBB capture from septal myocardial capture in patients undergoing pacemaker implantation?
Programmed deep septal pacing using an extra-stimulus technique is a diagnostically valuable novel maneuver to confirm left bundle branch capture by exploiting differences in refractoriness between the LBB and septal myocardium.
May facilitate LBB capture confirmation during implantation; hypothesis-generating and requires prospective validation before routine use.
Background During permanent deep septal pacing, it is important to confirm left bundle branch (LBB) capture. Objective The effective refractory period (ERP) of the working myocardium is different than the ERP of the LBB; we hypothesized that it should be possible to differentiate LBB capture from septal myocardial capture using programmed extra-stimulus technique. Methods In consecutive patients undergoing pacemaker implantation who received pacing lead in a deep septal position programmed pacing was delivered from this lead. Responses to programmed pacing were categorized on the basis of QRS morphology of the extrastimuli as: myocardial (broader QRS, often slurred), selective (narrower QRS, preceded by an isoelectric interval) or non-diagnostic (unequivocal change). Results Programmed deep septal pacing was performed 269 times in 143 patients; in every patient with the use of an 8-beat basic drive train of 600 ms and when possible also during supraventricular rhythm. Responses diagnostic for LBB capture were observed in 114 (79.7%) of patients. Selective LBB paced QRS was more often seen when premature beats were introduced during the intrinsic rhythm rather than after the basic drive train. The average septal-myocardial refractory period was significantly shorter than the LBB refractory period: 263.0±34.4 ms vs. 318.0±37.4 ms. Conclusions A novel maneuver for the diagnosis of LBB capture during deep septal pacing, was formulated, assessed and found as diagnostically valuable. This method, based on the differences in refractoriness between LBB and the septal myocardium is unique in enabling the visualization of components of the usually fused, non-selective LBB paced QRS complex.
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Jastrzębski et al. (2019) conducted an observational in Pacemaker implantation with deep septal pacing (n=143). Programmed deep septal pacing was evaluated on Responses diagnostic for LBB capture. Programmed deep septal pacing successfully diagnosed left bundle branch capture in 79.7% of patients by differentiating the refractory periods of the LBB and septal myocardium.
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