BACKGROUND: For the treatment of myocardial infarction with ST-segment elevation, primary angioplasty is considered superior to fibrinolysis for patients who are admitted to hospitals with angioplasty facilities. Whether this benefit is maintained for patients who require transportation from a community hospital to a center where invasive treatment is available is uncertain. METHODS: We randomly assigned 1572 patients with acute myocardial infarction to treatment with angioplasty or accelerated treatment with intravenous alteplase; 1129 patients were enrolled at 24 referral hospitals and 443 patients at 5 invasive-treatment centers. The primary study end point was a composite ofdeath, clinical evidence of reinfarction, or disabling stroke at 30 days. RESULTS: Among patients who underwent randomization at referral hospitals, the primary end point was reached in 8.5 percent of the patients in the angioplasty group, as compared with 14.2 percent of those in the fibrinolysis group (P=0.002). The results were similar among patients who were enrolled at invasive-treatment centers: 6.7 percent of the patients in the angioplasty group reached the primary end point, as compared with 12.3 percent in the fibrinolysis group (P=0.05). Among all patients, the better outcome after angioplasty was driven primarily by a reduction in the rate of reinfarction (1. 6 percent in the angioplasty group vs. 6.3 percent in the fibrinolysis group, P<0.001); no significant differences were observed in the rate of death (6.6 percent vs. 7.8 percent, P=0.35) or the rate of stroke (1.1 percent vs. 2.0 percent, P=0.15). Ninety-six percent of patients were transferred from referral hospitals to an invasive-treatment center within two hours. CONCLUSIONS: A strategy for reperfusion involving the transfer of patients to an invasive-treatment center for primary angioplasty is superior to on-site fibrinolysis, provided that the transfer takes two hours or less.