The normal QT interval is ... between the RR interval. If the T wave ends past the halfway point of the RR interval, it is prolonged. Due to the effects of heart rate, the corrected QT interval ...

The PR interval is the time from the beginning of the P wave (atrial depolarization) to the beginning of the QRS complex (ventricular depolarization). The normal PR interval measures 0.12-0.20 ...