This is why the entire duration of the ventricular repolarization is commonly associated with a measure including the QRS complex;
http://www.springerlink.com/content/l51836043ml8p154/;
The T wave represents ventricular repolarization and is longer in duration than depolarization (i.e., conduction of the repolarization wave is slower than the wave of depolarization). Sometimes a small positive U wave may be seen following the T wave (not shown in figure at top of page). This wave represents the last remnants of ventricular repolarization. Inverted or prominent U waves indicates underlying pathology or conditions affecting repolarization;
http://www.cvphysiology.com/Arrhythmias/A009.htm;
Ventricular repolarization: T wave
The last event of the cycle is the repolarization of the ventricles;
The ECG complex: P=P wave, PR=PR interval, QRS=QRS complex, QT=QT interval, ST=ST segment, T=T wave;
http://en.wikipedia.org/wiki/Electrical_conduction_system_of...