The V6-V1 interpeak interval: a novel criterion for the diagnosis of left bundle branch capture

Abstract

Aims We hypothesized that during left bundle branch (LBB) area pacing, the various possible combinations of direct capture/non-capture of the septal myocardium and the LBB result in distinct patterns of right and left ventricular activation. This could translate into different combinations of R-wave peak time (RWPT) in V1 and V6. Consequently, the V6-V1 interpeak interval could differentiate the three types of LBB area capture: non-selective (ns-)LBB, selective (s-)LBB, and left ventricular septal (LVS). Methods and results Patients with unquestionable evidence of LBB capture were included. The V6-V1 interpeak interval, V6RWPT, and V1RWPT were compared between different types of LBB area capture. A total of 468 patients from two centres were screened, with 124 patients (239 electrocardiograms) included in the analysis. Loss of LVS capture resulted in an increase in V1RWPT by ≥15 ms but did not impact V6RWPT. Loss of LBB capture resulted in an increase in V6RWPT by ≥15 ms but only minimally influenced V1RWPT. Consequently, the V6-V1 interval was longest during s-LBB capture (62.3 ± 21.4 ms), intermediate during ns-LBB capture (41.3 ± 14.0 ms), and shortest during LVS capture (26.5 ± 8.6 ms). The optimal value of the V6-V1 interval value for the differentiation between ns-LBB and LVS capture was 33 ms (area under the receiver operating characteristic curve of 84.7%). A specificity of 100% for the diagnosis of LBB capture was obtained with a cut-off value of >44 ms. Conclusion The V6-V1 interpeak interval is a promising novel criterion for the diagnosis of LBB area capture.

An Electrocardiographic Characterization of Left Bundle Branch Area Pacing-Induced Right Ventricular Activation Delay: A Comparison With Native Right Bundle Branch Block

“…Left ventricular activation time (LVAT) was calculated from QRS onset to the R wave peak in lead V6 (V6RWPT) ( 26 , 28 ). The interval between the R wave peak time in V6 and V1 was defined as the V6–V1 interpeak interval (V6V1 IPI) and used as an estimation of interventricular electrical dyssynchrony ( 29 ).…”

Direct and indirect capture of the left bundle branch: Dynamic retrograde atrial potential abrupt and gradual decrease

“…In this case, dynamic QRS morphologic changes served as a criterion for the LBB capture diagnostic. 4 When the QRS morphology changed and the stimulus-to–left ventricle activation time (Stim-LVAT) was decreased by ≥10 ms, 2 it was confirmed that left ventricular septum pacing changed to nonselective LBBP. This means that activation of the myocardium was achieved in addition to LBB.…”

Feasibility, safety and outcomes of upgrading to left bundle branch pacing in patients with right ventricular pacing induced cardiomyopathy

“…Meanwhile, several groups have been working on the establishment of novel evidence based, rather than arbitrary, criteria for differentiation between LBBP and LV septal pacing. [33][34][35] Although, all echocardiograms were analyzed anonymized, at random, and after the last patient ended follow-up, it cannot be fully excluded that outcomes may have been biased since pacing leads in the interventricular septum were often easily visible.…”

“…On the other hand, patients might have been classified as “successful attempt” in whom deep LV septal pacing (with secondary activation of the left sided Purkinje system) was performed instead of direct capture of the LBB. Meanwhile, several groups have been working on the establishment of novel evidence based, rather than arbitrary, criteria for differentiation between LBBP and LV septal pacing 33–35 …”