Treatment with cardiosphere-derived cells (CDCs) improves ventricular function in children with single ventricle physiology, according to the findings of the phase II, randomized, controlled PERSEUS study. A total of 41 patients with single ventricle physiology undergoing second-stage or third-stage palliation were randomly assigned to receive either intracoronary infusion of CDCs or standard care. The investigators found that at 3 months after treatment, ventricular function (primary outcome) was significantly improved in the CDC-treated group compared with controls (6.4% vs 1.3%; P = 0.003). “Although several clinical trials have suggested that somatic stem cell transplantation may not be effective in improving myocardial function after infarction in adults, our observations show infusion of CDCs in children with single ventricle physiology improves cardiac function and heart failure status,” conclude the investigators.