What does the T wave on an EKG indicate?

The T wave on an EKG represents ventricular repolarization. During the cardiac cycle, after the ventricles contract and eject blood into the arteries (a phase known as depolarization), they must then reset their electrical state in preparation for the next heartbeat. This resetting is shown as the T wave on an electrocardiogram.

Repolarization is crucial because it signifies that the heart muscle is recovering and getting ready for the next contraction. The T wave's characteristics, such as its shape and duration, can provide valuable information regarding the heart's electrical state and overall health, indicating whether there may be underlying conditions affecting cardiac function.

Atrial depolarization is indicated by a different component of the EKG called the P wave, while ventricular depolarization is represented by the QRS complex. Heart rate variability refers to the fluctuations in time intervals between heartbeats and is not directly represented by any single wave on an EKG but rather assessed over several cardiac cycles. Hence, the identification of the T wave as representing ventricular repolarization is essential for interpreting EKG results effectively.