Key Learning Points
Intervals and Segments
PR Outliers Page 4
- A normal PR Interval is between 0.12 and 0.20 sec.
- If the PR interval is greater than 0.20 sec it is called a First Degree AV Block
- A PR Interval less than 0.12 sec is short and may be the result of an accessory pathway(a).
QRS Interval Page 6
- The QRS Interval represents the time it takes for the ventricles to depolarize(a).
- The QRS Interval portrays the health of the ventricles and ventricular conduction system, specifically the HIS Purkinje system.
- The QRS Interval begins at the first deflection after the PR interval which will be a Q or R wave(b).
- The QRS interval ends after the last deflection which could be a R, S, R-Prime or S-Prime wave(c).
- A normal QRS interval is 0.10 sec or less.
