What Are T Waves?

Q: What are T waves?


A: The T wave is part of the graph in electrocardiography (ECG), which records the electrical activity of the heart over a period of time. In the graph, a T wave is a repolarization of the ventricles (chambers in the heart).

In general, a T wave is divided into two parts.

  • The first one is the left side of the T wave, from the beginning of the QRS complex to the apex of the T wave. This part represents the absolute refractory period, when neurons rest and do not send signals.
  • The other part is the last half of the T wave, which represents the relative refractory period.

Mostly, T wave changes provide more information than the QT interval. For instance, an abnormal T wave could suggest hyperkalemia (high potassium in the blood).


Keywords: T wave; electrocardiography; ECG

* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.