What does the S-T wave represent in the cardiac cycle?

The S-T wave segment on an electrocardiogram (ECG) represents the period during which the entire ventricles are depolarized. This phase follows the QRS complex, which indicates ventricular depolarization, and precedes the T wave, which represents ventricular repolarization.

During the S-T segment, the ventricles are in a relatively stable state where they are all electrically activated and contracting, allowing for effective blood ejection into the aorta and pulmonary arteries. This time frame is crucial as it signifies the completion of depolarization and the initiation of ventricular contraction. The significance of accurately interpreting the S-T segment can be profound in clinical practice, particularly in identifying conditions such as myocardial ischemia or infarction, where deviations from the normal baseline can indicate underlying pathologies.

Understanding the function of the S-T segment enhances your ability to analyze the cardiac cycle comprehensively, particularly in interventional radiology, where knowledge of cardiac rhythms is essential for patient safety during procedures.