Determining HR on strip (NCLEX)

Students Student Assist

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Hello!

I have learned different ways to determine the HR from an EKG strip, but still am a bit confused, especially as I'm studying for the NCLEX. What way do you use to determine the rate?

Thank you :)

Guest 360983

357 Posts

I'm lazy so I count the number of complete QRS complexes in a 6 second strip and multiply by 10. You can measure the number of large boxes between the same part of consecutive complexes (say between the start of one P and the start of the next P) and divide that number by 300. You can also measure the number of small boxes as I just described and divide that number by 1500.

Jayjormom

174 Posts

I always count the qrs complexes! Quick and easy and doesn't require a whole lot of math!!!

actsc1v8

13 Posts

Thank you so much!! This clarified things for me :)

G-manRN

7 Posts

There are a few ways to quickly check the HR. You can count the QRS complexes for 6 second strips or dividing the # of small boxes between each QRS complex into 1500 example: 19 boxes between them 1500/19 = ~79 HR. My personal favorite if it is a normal rhythm/rate is to just look at the big boxes and count down to the next QRS complex. If the next QRS falls one big box away(0.2 seconds) then the HR is 300. The next big box = 0.4 seconds away so the HR is 150. The next big box = 0.6 seconds away and the HR is 100 etc. So count down from 300, 150, 100, 75, 60 and you have a pretty accurate HR without having to do any math.

nurseprnRN, BSN, RN

1 Article; 5,115 Posts

G-man's explanation will make even more sense to you if you remember that all EKG paper runs under the pen at the same rate, that being 300 big boxes per minute (or 1500 little boxes per minute).

So if there's a QRS in every big box, (eek!) that means there are QRSs 300 times per minute.

If there is a QRS in every other big box, 150/minute (300/2)

Every third box, 100/minute (300/3)

Every fourth box, 75/minute (300/4)

Every fifth box, 60/minute (300/5)

Every 6th box, 50 (300/6)

and so forth

If you need a greater level of precision, divide the number of small boxes between the QRSs into 1500. Same formula.

If the heart rate is irregular, this will not work. If you have a whole minute strip, you count it out. If all they give you is a 6-second (1/10th of a minute) sample, you will have to assume it's representative of the whole minute, and multiply x 10. Caveat: They may be asking you if you can assume that....be sure before you do.

actsc1v8

13 Posts

Thank you guys so much!! This will be really helpful when I take my NCLEX this week :)

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