Figure 1. (A) The relation between the action potential and the ECG curve. Myocardial ischemia primarily affects the repolarization, which is reflected on ST-T changes on the ECG. (B) Note that the reference level for measuring deviation (elevation or depression) of the ST segment is the PR segment (the terminal portion of the PR interval). (C) and (D) Shows how to measure the magnitude of ST segment elevation and ST segment depression. The J 60 point is located 60 ms after the J point.




















