Automatic measurement of stimulation to maximum negative dv/dt in V5 and V6 leads to confirm left bundle capture for conduction system pacing

Abstract Introduction Left bundle area conduction system pacing is obtained when the ventricular pacing lead is implanted into the right ventricular septum and captures the left bundle branch, demonstrated by right bundle branch morphology in the lead V1 and short stimulation to R-wave peak time (SRWPT) in leads V5 or V6. Manual measurements are challenging and result in significant variability. Maximum negative dv/dt in leads V5 and V6, occurring immediate after maximal lateral wall depolarization, represents the ideal measurement of synchronicity of left ventricular depolarization, as suggested by the guidelines. Objective To test feasibility of automatic algorithm to measure the maximum negative dV/dt in comparison to manual SRWPT measurement in V5 and V6. Method Data was collected from 7 patients with confirmed left bundle branch capture. Three trained operators manually measured SRWPT in leads V5 and V6 (Figure A). An algorithm capable of automatically measuring stimulation to maximum dv/dt was retrospectively applied to the same measured beats. Variability and correlation of measurements was compared between manual and automatic using the Bartlett Test for equal variance. Results In total, 137 individual beats were measured in the 2 leads by three operators resulting in 822 manual measurements. The mean variability of SRWPT in V5 and V6 was 2.9 ± 0.7 msec and 3.1 ± 1.1 msec, respectively (inter-operator correlation of 0.83). In contrast the stimulation to max negative dv/ dt mean variability in V5 and V6 was 1.3 ± 0.4 msec and 1.2 ± 0.5 msec, respectively (P < 0.001). The comparison of variation in measurement between manual and automatic measures are shown in a box and whisker plot in figure 2. Conclusion Manual measurement of SRWPT can be challenging resulting in higher variability compared to an automatic algorithm measuring max negative dv/dt. This study demonstrates the feasibility of automatic interval measurement in conduction system pacing; however, further studies are required to validate the reliability of such tool.Fig 1.Example ECG interval measurement