Feb 4, 2021 · The normal PR interval is between 120 – 200 ms (0.12-0.20s) in duration (three to five small squares). If the PR interval is > 200 ms, first degree heart block is said to be present.

In this article, I am going to show you a simple way on how to measure the PR interval. At the end of the article, you can test your knowledge on how to measure PR intervals.

Oct 30, 2025 · The PR interval is measured using an electrocardiogram, also called ECG or EKG. This is a painless test performed on cardiac patients in order to measure the electrical conductivity of the …

Mar 17, 2025 · How to determine whether or not the PR Interval is normal. What kind of information it brings.

This video explains how to measure the PR interval on an EKG strip. In order to do this you must know how the normal measurement of a PR interval and how to count the small blocks...

Aug 16, 2025 · Learn how to interpret the PR interval on ECG — including normal physiology, how to measure it, causes of short and prolonged PR intervals, PR depression in pericarditis and atrial …

Remember that the PR interval starts at the start of the P wave and ends at the start of the QRS: There are 2 questions you must ask when you measure the PR interval:

Dec 4, 2025 · To calculate the PR interval, count the number of small squares spanned between the start of the P wave and the start of the QRS complex. For instance, if the interval covers four small …

Nov 8, 2021 · Calipers, marked paper or counting small boxes methods can be used to determine PR Intervals. Normally this interval is 0.12 to 0.20 seconds (3 to 5 small boxes) in adults, longer in …

Measuring the PR interval involves identifying the P wave and QRS complex on an EKG trace. Use a ruler or calipers to measure the distance between their peaks, or count the squares on the grid …