This randomized, double-blind, placebo-controlled trial evaluated the effects of transendocardial delivery of autologous bone marrow mononuclear cells (BMCs) in 92 patients with chronic heart failure. The primary objectives were to determine if BMC administration improved left ventricular end-systolic volume (LVESV), maximal oxygen consumption, or reversibility of perfusion defects on single-photon emission computed tomography (SPECT) compared to placebo at 6 months. Results showed no statistically significant differences between the BMC and placebo groups in changes in LVESV, maximal oxygen consumption, or reversible defect size by SPECT. There were also no differences in any secondary outcomes, including echocardiographic or clinical measures. Thus, tran