The purpose of this study is to evaluate the efficacy and safety of a single transendocardial delivery in the cardiac catheterization laboratory of human bone marrow-derived allogeneic MPCs (rexlemestrocel-L) for improvement in clinical outcomes (heart failure major adverse cardiac events \[HF-MACE\]), preventing further adverse cardiac remodeling (left ventricular end systolic volume \[LVESV\] and left ventricular end-diastolic volume \[LVEDV\]), and increasing exercise capacity (six-minute walking test \[6MWT\]) in participants with chronic HF due to LV systolic dysfunction of either ischemic or nonischemic etiology who have received optimal medical/revascularization therapy.
