As discussed earlier, acute transmural ischemia results in elevation of the ST segment in leads overlying the ischemic region (A) reflecting the flow of injury current away from the overlying electrodes during the TQ segment (causing TQ depression) and towards the overlying electrodes during the ST segment (causing true ST elevation). In leads overlying a non-ischemic region, (B), the opposite occurs. The injury current flows towards the electrode during the TQ segment (causing TQ elevation) and away from the electrode during the ST segment (causing true ST depression).