Which wave represents ventricular diastole in the cardiac cycle?

The QRS complex represents ventricular depolarization, not diastole. The correct wave that corresponds to ventricular relaxation or diastole is the T wave, which reflects the repolarization of the ventricles after contraction. During ventricular diastole, the ventricles fill with blood in preparation for the next heartbeat. This filling occurs after the electrical impulse has stimulated the ventricles to contract, which is indicated by the preceding QRS complex. Therefore, understanding the sequence of electrical activity and the corresponding phases of the cardiac cycle is crucial for interpreting these waves accurately in an electrocardiogram (ECG).