In which part of the waveform does ventricular repolarization occur?

Ventricular repolarization occurs during the T wave of the ECG waveform. This is the phase in which the ventricles recover from the electrical activation that causes contraction, allowing them to prepare for the next heartbeat. The T wave visually represents this repolarization process, as it shows the transition of the ventricular myocardium returning to a resting state after depolarization.

The other intervals and complexes on the ECG serve different purposes. The QT interval encompasses both ventricular depolarization (represented by the QRS complex) and repolarization (T wave), indicating the total time for the ventricles to contract and then recover. The QRS complex specifically represents ventricular depolarization, which triggers the contraction of the ventricles, while the PR interval corresponds to the time it takes for the electrical impulse to travel from the atria to the ventricles, involving the atrial depolarization and the conduction through the AV node. Therefore, the T wave is the correct representation of ventricular repolarization.