An ECG monitoring system analyzes ECG signals of leads associated with different anatomical locations of the body for evidence of ST elevation in the lead signals. The ST elevation and depression measurements of the leads are plotted in a graphical display organized in relation to the anatomical points which are the sources of the lead signals. The locations of the plotted measurements in the anatomically-oriented display indicate the identity of a specific coronary artery or branch as a possible culprit coronary artery for an acute ischemic event, as well as the possible severity of the event from the magnitudes of the plotted signals. A clinician can identify a suspect culprit coronary artery from a quick glance at the graphical display.