In an ECG, what does the T wave represent?

The T wave on an electrocardiogram (ECG) is an important component that represents ventricular repolarization. This phase is crucial because it signifies the return of the ventricles to their resting state after the contraction (depolarization) that occurs during the QRS complex. During the T wave, potassium ions exit the myocardial cells, allowing the heart muscle to reset for the next cardiac cycle.

Understanding the role of the T wave is vital for interpreting ECGs, as abnormalities in the T wave can indicate various cardiac conditions, such as ischemia or electrolyte imbalances. Recognizing that the T wave represents the final phase of the cardiac cycle helps in understanding how the heart prepares for the subsequent heartbeat.

In contrast, other options represent different electrical events in the heart. Atrial depolarization occurs before the T wave and is depicted by the P wave. Ventricular depolarization is represented by the QRS complex, which follows the P wave. The concept of heart rhythm irregularity refers to variations in the heart's rhythm and is not directly associated with any specific wave on the ECG, including the T wave.