The<unk>  represents the repolarization (or recovery) of the ventricles. The interval from the beginning of the QRS complex to the apex of the<unk>  is referred to as the absolute refractory period. The last half of the<unk>  is referred to as the relative refractory period (or vulnerable period).
T wave
P wave
QRS complex
V wave
A wave
ST interval
PR interval
Theta wave