Comparable acute hemodynamic effects of left bundle branch pacing delivered from the right and left ventricular septum

Background Left bundle branch area pacing (LBBAP) is conventionally performed from the right ventricular septum. The haemodynamic effect of LBBAP delivered from the LV septum (L-LBBAP) compared to right-sided LBBAP (R-LBBAP) has not been studied. We assessed the acute hemodynamic effects of L-LBBAP and R-LBBAP. Methods Eight patients were implanted with a permanent LBBAP and underwent invasive temporary pacing and hemodynamic testing with measurement of the maximum rate of left ventricular (LV dp/dtmax) and of right ventricular pressure rise (RV dp/dtmax). R-LBBAP was performed using the permanent LBBAP device in situ and L-LBBAP was performed using a temporary catheter within the left ventricle. Results There was no significant difference in the mean increase in ∆ LV dp/dtmax compared to baseline between R-LBBAP and L-LBBAP (72.1 ± 128.6 mmHg/s vs. 99.1 ± 148.1 mmHg/s respectively; P = 0.51). Similarly, ∆ RV dp/dtmax did not differ significantly between R-LBBAP and L-LBBAP (-21.1 ± 22.7 mmHg/s vs. -22.8 ± 17.1 mmHg/s, respectively; P = 0.95). The mean QRS duration reduction was 25.4 ± 10.0ms and 31.6 ± 5.7ms for R-LBBAP and L-LBBAP respectively (P = 0.60). Conclusion Both R-LBBAP and L-LBBAP produced comparable effects on biventricular hemodynamics and QRS reduction. Both improved LV contractility at the expense of RV contractility.