What does the T-wave signify?

The T-wave on an electrocardiogram (ECG) represents ventricular repolarization, which is the process in which the ventricles recover and restore their resting electrical state following contraction. During this phase, the cardiac muscle cells in the ventricles reset their ion concentrations across the cell membrane, which is crucial for the heart to prepare for the next contraction. Accurate interpretation of the T-wave is essential in assessing heart health, as abnormalities in this wave can indicate various cardiac conditions, such as ischemia or electrolyte imbalances.

In contrast, the options related to atrial depolarization, ventricular contraction, and the rest phase of the atrium refer to different heart electrical activities that are represented by other parts of the electrocardiogram. Atrial depolarization is indicated by the P-wave, ventricular contraction is reflected in the QRS complex, and the rest phase of the atrium is not specifically represented on a standard ECG. Thus, understanding the role of the T-wave in the cardiac cycle underscores its importance in the overall assessment of heart rhythm and function.