The purpose of this study is to determine if patients with heart failure (HF, meaning a weak heart) with left ventricular ejection fraction (LVEF) ≤ 50% and with an abnormal heart beat can benefit from having pacemaker leads placed in a different location in the heart. We know that people with a weak heart and an abnormal heart beat can benefit from having a pacemaker. Participants in this study will be randomly assigned (like flipping a coin) to one of two treatments (A or B), both of which are standard of care heart pacing treatments:
A. Pacing the heart from two locations in the left ventricle (lower left chamber of the heart)
B. Pacing the heart from one of two other places in the heart (the "His" or the left bundle branch)

The purpose of this study is to compare side by side these two treatments and evaluate if one is better than the other.