Which characteristic defines a T wave in ECG interpretation?

The T wave on an electrocardiogram (ECG) is defined by the process of ventricular repolarization. This occurs after the ventricles have contracted and pumped blood out of the heart. During repolarization, the electrical activity of the heart muscle returns to its resting state, and this is represented visually on the ECG as the T wave.

Understanding the role of the T wave in the cardiac cycle is crucial for interpreting ECG readings accurately. It reflects the time when the ventricles are recovering and preparing for the next contraction. The T wave's shape and size can provide valuable information about the heart's electrical stability and can indicate potential issues if abnormalities are present.

In contrast, the other options refer to different phases or aspects of the cardiac cycle. For instance, atrial depolarization is represented by the P wave, while ventricular depolarization is reflected in the QRS complex, and heart rhythm assessment is a broader analysis that involves interpreting multiple waveforms, including the P wave, QRS complex, and T wave. Therefore, recognizing that the T wave specifically indicates ventricular repolarization is essential for accurate ECG interpretation.