ECG Measurement 2

The horizontal axis measures time. The vertical axis measures voltage or amplitude. 

1 millivolt m(V) is 2large boxes high. Figure 8 shows the major ECG intervals and their normal measurements and durations.

ECG Interval /Complex

PR interval Measures from the beginning of the P wave to the beginning of the Q wave

Normal: 0.12 ot 0.20 sec

QRS complex Measures from  the beginning of the Q wave to the end of the S wave

Normal: <0.12 sec

QT interval Measures from  the beginning of the  Q wave of the end of the  T wave

Normal: Needs to be corrected for heart rate-usually 0.44 to 03.2 sec (heart rate of 60 to 10 bpm for both men

and women)