ST Segment Lesson and Quiz 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. EKG Basics Quiz Table of Contents Introduction 1EKG Paper 2EKG Nomenclature 3EKG Interpretation 4Rhythm 5Heart Rate 6P Wave 7PR Interval 8QRS Complex 9T Wave 10QT Interval 11ST Segment Conceptos Básicos ECG