What are normal values for waves and intervals on electrocardiography (ECG)?

Normal values for waves and intervals are as follows:

• RR interval: 0.6-1.2 seconds

• P wave: 80 milliseconds

• PR interval: 120-200 milliseconds

• PR segment: 50-120 milliseconds

• QRS complex: 80-100 milliseconds

• J-point: N/A

• ST segment: 80-120 milliseconds

• T wave: 160 milliseconds

• ST interval: 320 milliseconds

• QT interval: 420 milliseconds or less if heart rate is 60 beats per minute (bpm)