What does the ST segment on an ECG represent?

The ST segment on an ECG is significant because it reflects the interval between ventricular depolarization and repolarization. This phase occurs after the QRS complex, which indicates the end of ventricular depolarization, and before the T wave, which represents ventricular repolarization. During the ST segment, the myocardium is in a state of plateau depolarization, meaning the cardiac muscle cells are maintaining their depolarized state before they start to repolarize.

Monitoring the ST segment is crucial in clinical practice, as changes in its elevation or depression can indicate myocardial ischemia or injury, thus serving as an important diagnostic tool in various cardiac conditions. Overall, the ST segment helps to provide information about the heart’s electrical activity and further indicates how the heart is responding to oxygen demand.