The present study investigated the effects of intravenous adenosine on myocardial perfusion and segmental contractile function when used as an adjunct of primary percutaneous coronary intervention (PCI) in patients with acute ST segment elevation myocardial infarction (STEMI). Patients were randomly assigned to receive intravenous adenosine (n=35) or saline (n=34) within 12h of STEMI. Myocardial contrast echocardiography (MCE) and velocity vector imaging (VVI) were performed 7days after primary PCI. Serial echocardiography was performed on Days 7 and 30. Capillary blood volume (A; 6.34 +/- 1.98 vs 5.64 +/- 1.84dB; P=0.03) and myocardial blood velocity (beta; 0.13 +/- 0.04 vs 0.1 +/- 0.04/s; P=0.01) were higher in the adenosine group than in control patients. Myocardial blood flow (Ax beta) was 0.82 +/- 0.37dB/s with adenosine compared with 0.57 +/- 0.4dB/s in control patients (P<0.01). Improvements were seen in the adenosine compared with the control group in terms of myocardial wall strain(13.52 +/- 5.61% vs 11.47 +/- 5.25%, respectively; P=0.03), strain rate (1.08 +/- 0.52 vs 0.90 +/- 0.44/s, respectively; P=0.03) and segmental ejection fraction (53.66 +/- 12.04% vs 48.40 +/- 14.99%, respectively; P=0.03). There was a correlation between myocardial perfusion in apical anterior segments, peak systolic strain (P=0.001), strain rate (P=0.001) and segmental ejection (P<0.001). Global contractile function was better in the adenosine-treated than control group. At the 1month follow up, there were no significant differences between groups in terms of the incidence of recurrent angina or heart failure. The results of the present study suggest that periprocedural intravenous adenosine contributes to improvements in myocardial perfusion, segmental wall motion and global contractile function in patients with acute myocardial infarction undergoing primary PCI.