- Measurement of the PR interval reflects the amount of time from the beginning of atrial depolarization to the beginning of ventricular depolarization.
- Plainly stated, this measurement is from the beginning of the P wave to the beginning of the QRS complex.
- The normal range for PR interval is: 0.12 – 0.20 seconds (3 to 5 small boxes)
- It is important that you measure each PR interval on the rhythm strip.
- Some tracings do not have the same PRi measurement from one cardiac complex to the next. Sometimes there is a prolonging pattern, sometimes not.
- If the PR intervals are variable, report them as variable, but note if a pattern is present or not.