The TIMI scoring system has been used extensively to report infarct related artery patency in trials of thrombolytic treatment. In the initial studies no distinction was made between TIMI 2 and 3 flow, both being considered to represent an open artery. Karagounis and colleagues reported data from the TEAM-2 study in 1992 suggesting that the outcomes of patients with TIMI 2 flow were closer to those of patients with no reperfusion (TIMI 0/1) than they were to patients with “complete” reperfusion (TIMI 3).1 The GUSTO angiographic substudy reported TIMI 2 and TIMI 3 flow as separate groups; 30 day mortality was 8.9% for patients with TIMI 0/1 flow at 90 minute angiography compared to 7.4% for TIMI 2 flow and 4.4% for TIMI 3 flow. The size of the study precluded this impressive 40% relative reduction in mortality between TIMI 2 and 3 from reaching significance (p = 0.08), but left ventricular function was significantly better in patients achieving TIMI 3 flow compared to TIMI 2 flow.2 If we accept that the goal of treatment in acute myocardial infarction is to achieve complete (TIMI 3) reperfusion then it becomes critically important to be able to identify failure to achieve TIMI 3 flow simply and rapidly so that additional treatment strategies or randomisation in appropriate trials can be considered. Two papers in this issue of Heart describe similar methods of assessing reperfusion and importantly report patients with TIMI 2 and 3 flow as separate groups.3 ,4