Left vs Left Randomized Clinical Trial

In this prospective, randomized, multi-center clinical trial, the investigators aim to prospectively evaluate the comparative effectiveness His or Left bundle branch pacing (His/LBBP) vs. biventricular pacing (BiVP) in patients with heart failure due to left ventricular systolic dysfunction (LVEF≤50%) and with either a wide QRS (≥130 ms) or with/anticipated \>40% pacing who are already receiving current standard heart failure pharmacological therapy by assessing all cause death and heart failure hospitalization at the end of the study. Additional formal secondary objectives include evaluation disease-specific quality and psychological adjustment changes at 1 year after device implant and evaluation of a composite of death of any cause or heart failure hospitalization or more \>15% increase in the left ventricular end-systolic volume index at the end of the study.