The beneficial effects of a timely recanalisation of the infarct-related coronary artery in ST-elevation myocardial infarction may be limited at the microvascular level by reperfusion injury and distal microembolisation. These complications carry ominous consequences for both prognosis and survival. The importance of reperfusion injury and microembolisation has been progressively more recognized and many different preventive and therapeutic interventions have been developed to minimise these complications. In the present contribution some simple elements of value in the understanding, recognition and differential diagnosis of reperfusion injury and coronary microembolisation are provided.