Table 4.3 Measurements of the normal complex and interval duration


Guideline normal values for ECG wave and

complex durations and intervals IY lead)

Duration No. small boxes
(sec) (25 mm/sec)
P wave < or = 0.16 4.0
PR interval < or = 0.5 12.5
QRS complex < or = 0.14 3.5
QT interval < or = 0.6 15.0