ST Segment & U Wave - EKG Basics.

The ST segment represents the early part of ventricular repolarization.

The ST segment is the line that from the end of the QRS complex to beginning of the T wave. Normally the ST segment is flat relative to the baseline.

The U-wave is a small upright, rounded bump. When observed, it follows the T-wave. U waves greater than 0.15mv (1.5 boxes) are considered abnormal.