Methods: Patients with STEMI treated with PCI <12 hours after symptom onset were randomised (1:1) to G-CSF (10 μg/kg/d) or placebo for 6 days in a double-blind design. Other inclusion criteria: age 20-70 years, culprit lesion in a large coronary artery, and peak CKMB >100 microgram/L. Follow-up was done after 1, 5 and 6 months, with an angiogram at 5 months.