The cardiAMP Heart Failure trial, a randomized, double-blind pivotal study enrolling patients with ischemic cardiomyopathy, left ventricle ejection fraction 20% to 40%, is the first to incorporate a cell potency score in screening criteria. In addition to standard screening studies, including 6-minute walk distance, New York Heart Association heart failure classification and Minnesota Living with Heart Failure Questionnare, patients undergo screening  mini-bone marrow aspiration to measure surface marker expression and functional properties in an assay devised to identify  therapeutically  potent bone marrow stem cells. Patients meeting the potency assay requirement are randomized to transendocardial autologous bone marrow mononuclear cells or sham procedure. The goal is a high effective cell dose, that is, a high number of bone marrow cells [target 2×10(8)] isolated  from selected patients and administered with efficient intramyocardial delivery by  Helix/Morph injection system. The primary outcome is change in 6-minute walk distance adjusted for major adverse cardiovascular events at 12 months.