LVSP and LBBP result in similar or improved LV synchrony and hemodynamics compared to biventricular pacing

Abstract

Abstract Background The effect of left ventricular myocardial septal pacing (LVSP) and left bundle branch pacing (LBBP) on ventricular synchrony and LV hemodynamics is poorly understood in unselected cardiac resynchronization therapy (CRT) patients. Aim To investigate the impact of LBBP and LVSP on ultra-high-frequency ECG (UHF-ECG) ventricular synchrony and hemodynamics in CRT patients. Methods In consecutive CRT patients with LBBB, ventricular synchrony was assessed using UHF-ECG. LV hemodynamics was assessed using invasive systolic blood pressure measurement during multiple transitions between LBBP, LVSP, and biventricular pacing (BVP). LV synchrony was assessed by LV lateral wall delay (LVLWd) from the first to the last from V5-V8 activations. Hemodynamic effects were expressed as relative changes in systolic blood pressure. Results Thirty patients with an LVEF of 29 ± 6% and mean QRSd of 169 ± 24 ms were included. Twenty had non-ischemic cardiomyopathy. QRSd during BVP, LVSP, and LBBP was the same, but LBBP provided shorter LVLWd than BVP (-9 ms (-16; -4), p = 0.004); the difference between LVSP and BVP was not significant (-4 ms (-10;2), p = 0.2). LBBP was associated with higher systolic blood pressure than BVP (4% (2; 5) p < 0.001), while LVSP was not (1% (1; 2), p = 0.1. LV hemodynamic improvements during LBBP and LVSP vs. BVP were more pronounced in non-ischemic than ischemic patients. Conclusion The differences in ventricular synchrony between LBBP, LVSP, and BVP were demonstrated using UHF-ECG but not QRSd. LBBP, but not LVSP, was associated with better LV synchrony and hemodynamics than BVP.Local activation times in V1–V8Ventricular dyssynchrony and hemodynamic